Concrete cube Failure -Acceptance Criteria and Is Code

Concrete cube Failure -Acceptance Criteria and Is Code
Concrete Cubes

Concrete cube Failure

The Word “Concrete cube Failure” is too difficult to hear for a civil engineer and quality engineer at construction sites,

It is too difficult to get approval of any structure if the cube fails in strength test,

Many times the Concrete cube failure leads to the demolition of the Structure or Rework,

Rework is not profitable for any construction project.

What happens if a concrete cube fails?

Why do concrete cubes fail?

Concrete Cube Acceptance Criteria➱

Before going to acceptance standards immediately, we’ll go step-by-step in the direction of it,

In order that we will additionally be in a position to establish the basic causes and does concrete actually failed in the compressive strength check.

First, we ought to be properly privy to the right way to sampling and cube casting exercises,

If this goes fallacious your result would possibly point out knowledge that might be concluded.

Now you probably did the appropriate sampling and dice-casting exercise, let’s transfer to the testing half.

You know we did numbering on the Concrete cube and cube number one,2 &Three represents pattern number one, cube quantities 4,5&6 represent sample no 2 and so forth.

Why we numb and we should take cubes for testing in accordance with pattern?

In statistical evaluation and discovering root causes of failure, it helps quite a bit.

Concrete cube Failure -Acceptance Criteria and Is Code
Concrete cube failure

Acceptance Criteria

As per IS 456, the person’s cube strength shouldn’t have variation greater than + / – 15% of the common of the three cubes.

Why concrete cube test is carried out?

In case you get extra variation in any check end result, how one can find the basic explanation for it.

Say you’re testing Three cubes and the numbers written on it are in serial and represent a pattern.
Say you’ve got a cube numbered 4,5 & 6 – by numbers I can say it’s a pattern no 2 and brought after x cum of concrete.

If you’ve got Concrete cube numbers like 3,5&7 taken for testing – it gained’t characterizes a single pattern,

As a result it’s a mix of a number of patterns.

What is the concrete cube test?

Always do confirm cubes taken for testing at any age are from identical pattern.

Now you’ve got Concrete cubes which characterize single patterns and identical workmen who stuffed it.

What is quality of cement and how to check

Suppose you bought outcomes like 15, 20 and 25 mpa.

What it’ll point out – it’ll point out that, there may be a subject in cube casting and you may discard these outcomes simply.

So this will provide you with an influence to have higher Quality management as a result of you recognize the rationale of failure and the place to take motion.

Concrete cube Failure -Acceptance Criteria and Is Code
Concrete cube testing

One single pattern of three cubes cast by a single individual and numbered accurately,

Won’t ever present variation in outcomes and you’ll all the time get outcomes with lesser variation than +/- 15%.

When it’s greater than this, it signifies Concrete cube casting accomplished improperly otherwise you took pattern cubes incorrectly for testing.

Hope you’ll by no means see flowery outcomes like the above instance after implementing it and might catch the root causes of failure simply by eliminating the risk of cube sampling and casting challenge.

So transfer on to acceptance standards,

IS 456, specifies the acceptance standards for compressive in addition to flexure power.

As flexure is 0.7 of sq. root of compressive strength, it is very important get handed in compressive power outcomes.
When we do cube testing, we write its leads to cube check register with serial numbers, say 1 is xyz date concrete from abc location,

What are the Properties of Concrete

And 2 is different date concrete from the ghi location and so forth.

When we examine acceptance standards,

IS says the commonality of Four non-overlapping consecutive check outcomes shouldn’t be lower than fck + 0.85 x standard deviation Or fck + 3 mpa (whichever is greater) for grades of concrete M20 and above.

What is implied by Four non-overlapping consecutive checks – it means while you common out Four check outcomes for acceptance standards,

They need to not overlap in calculations.

Acceptable averages

1,2,3&4, 5,6,7 & 8 and so forth serial quantity smart outcomes ought to be common out.

If you do like averaging beneath

1,2,3&4

If you’ve got low outcomes at 6 and eight and in case you attempt to make averaging like 3,4,5 & 6 – then it overlaps to make you profit by tweaking,

This isn’t permissible and that means of Four non-overlapping consecutive check outcomes.

If you’ve got good high-quality management at concrete,

Then your standard deviation will likely be lower than 2 or barely extra.

In these instances, or in most instances relevant acceptance standards will likely be all the time like fck + Three mpa.

What is consistency test of cement

Sometimes there’s a risk that, in one of many check patterns,

You would possibly get decreased outcomes and which makes that group of Four non-overlapping consecutive check-end results not in a position to meet acceptance standards.

In that scenario, IS 456 additionally specifies that individual check pattern outcomes shouldn’t be lower than

fck – Three mpa for M20 and above grade concretes.

So you also need to examine these standards when a single pattern have decreased outcomes.

Each check outcome ought to meet fck + 3mpa standards as a way to guarantee no failure and detect the issues at the earliest.

Also, it is very important to observe failure patterns to get clues on what is perhaps fallacious or OK.

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Quality of Cement-How to check

Quality of Cement-How to check
Cement Bags

Quality of Cement-how to check when it’s obtained at Construction site?

Do you understand, when concrete fails, one of many offender could be the Quality Cement.

It is necessary to test the Quality of Cement when it’s obtained at web site to make sure no failure and stoppage in undertaking resulting from dangerous high quality of cement.
Cement is transported within the luggage and bulkers.

When Cement attain at web site, do test following in an effort to make sure the cement is of fine high quality or not.

Check for ISI mark on the cement bag (This tells model is commonplace and follows the steps to make sure product high quality.

And in such instances third celebration testing report will not be necessary.

However you could get finished third celebration take a look at if shopper calls for otherwise you wish to do)

Check the Cement manufacturing particulars printed on aspect of bag for week,

Month and 12 months of producing to know the quality of cement initially

When week 1 begin and on which day in calendar (Quality of cement)➱

Week 1 begins on the first Jan of yearly.
The day on 1st date will adopted as a begin of week.
Say on 1st Jan, its Tuesday then week additionally begins on each Tuesday.

After checking the manufacturing particulars, do test how a lot previous is cement.
It is recommendation to eat the cement inside three months from manufacturing.
Because nobody is aware of the circumstances the place cement is stocked by a provider / dealer.

Insist your organization to purchase cement instantly from producer,

This make sure you get contemporary cement and no alteration

or damages to cement resulting from storage provider / merchants place.

Printing of Manufacturing week on bag occurs after bag is loaded with cement on a conveyor by which luggage are despatched both for stacking or instantly in wagon (at firm nobody use iron hooks)
Printing is robotically finished,

So someday you could get luggage on which the manufacturing particulars will not be printed accurately (Such instances you must inform the producer about this,

And get the written affirmation from them through e mail earlier than accepting it.

This may even make sure the rectification in printing course of and different engineers will obtain luggage with clear print on luggage)

Also i want to let you know that instantly order luggage haven’t on the market or not for retail printed on it.

A bag having worth written on it’s produced for retail sale.

And also you would possibly get a really previous luggage should you order it by retailer.

Do not settle for the cement which is greater than a month previous (Ensure you set this level in buy order to keep away from dispute in future).

Check the load of cement bags At Random To Know the Reality➱

In India Cement business wont look after the standard of cement, as soon as it’s dispatched from their manufacturing unit.

Cement is transported to their storage yards throughout India, max by means of prepare.

On relieving cement at unload level at railway station, buggers begin taking part in with that cement baggage with iron hook.

No Quality man from that producer will object this damaging of packing by these unskilled labours.
No producer have energy to switch these native labours at every station.

They can change the design and substitute all baggage as an alternative of making an attempt to switch labour which is inconceivable.

As a Engineer all of us ought to write to all cement producer to do one thing in an effort to safeguard the dealing with of cement.

Coming again to the purpose, on account of improper dealing with

And puncturing of cement baggage at a number of location,

There’s a chance that cement in baggage wont weight precisely or above 50 Kg and individuals who makes use of customary as bag for doing their daily work will get extra failure.because the bag might not be bag or 50 Kg.

So you will need to confirm the bag weight is above or equal to 50 Kg to keep away from failure in concrete as some one would possibly use a bag weighting lower than 50Kg as a bag

And do concrete which change an entire lot arithmetic and chemistry of concrete produced.

Manufacturers are privy to these losses on account of dealing with, as an alternative of correcting it,

that they had elevated the amount of cement in every bag to make sure 50Kg is delivered in regular transport loss.

After verifying the freshness on cement we will additional examine it for engineering properties.

Quality of Cement-How to check
Stacking Plane of Cement 

Check the temperature of cement in packed bag Only➱

Sometimes chances are you’ll obtain a sizzling cement in bag,

It doesn’t imply that the hydration course of is began in it.

When cement is immediately loaded after manufacturing, it might be sizzling as much as 50 degree,

In such instances retailer cement for two to three days earlier than utilizing in an effort to permit it for cooling.

This occurs when order is greater than provide of cement.

If we use scorching cement false set might happen in concrete produced with it.

Which means concrete will turn into stiff after mixing it, to regain the plasticity, remixing needs to be performed.

Or mixing time of such concrete have to be elevated.

Check for Physical Properties Of Cement(To Know The Quality Of Cement)➱

Color of The cement➱

It relies upon totally on the colour of lime stone which is used to manufacturing of the identical

and the opposite efficiency enhancer components like flyash.

Cement in the direction of off-white shade doesn’t imply it’s unhealthy or have extra flyash or some other components (Example – AAC Cement – it have whitish lime stone,so shade is barely faint than gray shade)

Color of cement usually from shade of gray could also be darkish or could also be faint.

You ought to know why it’s faint or darkish (Ask your organization to rearrange go to to producer plant in an effort to perceive manufacturing higher.Such visits are prepare by producer freed from value on demand by the shoppers).

Smoothness➱

When you’re taking some cement in your fingers and rubbed it, it’s going to really feel silky easy as a consequence of fineness of cement.

If grinding will not be performed correctly, you’ll really feel the roughness in it.
If roughness noticed, test the fineness of cement.

What is Consistency test of Cement

Properties of Concrete it’s mix and types

Lumps in baggage➱

Lumps kinds in baggage as a consequence of lifeless weight on it referred to as as gentle lump which get breaks once we roll the bag.

Hard lumps – kinds as a consequence of to hydration of cement as a consequence of moisture contact

or direct contact in water throughout transport corresponding to rain water entered in bag.

if that is so cement needs to be rejected.

Contamination➱

Take handful of cement and throw it within the water, it ought to float for someday after which sink in water.

If its immediately sinking in water, it exhibits cement is modified after dispatch from plant

and should lead to failure (In such instances cubes needs to be casted and checked for 1 day power,

if it fails in it, cement needs to be rejected)

Consistency of Cement➱

It exhibits usually the water demand by cement, extra it demand larger the water cement ration goes and vice a versa.

In common normal consistency ranges between 27 to 34%

Older cement might present decrease water demand as a consequence of partly hydration of cement.

Also much less finer cement tends to much less water demand (coarser materials have much less floor space than finer materials).

Take the checks of Conistency of cement at 27 +/- 2 degree with relative humidity of 65 +/- 5% as per IS 4031 half 4.

No want to fret in case your lab will not be setup with such a precision,

You may nonetheless do a consistency take a look at and report the consequence as per your lab temperature

and confirm every consequence with outcomes obtained in earlier identical setting.

Compressive Strength Of Cement Cubes➱

A great engineer all the time do test for the compressive power of cement for every obtained batch of cement.

This guarantee no failure in actual work.

As the lab circumstances aren’t normal in case of many of the websites,

engineer can evaluate his outcomes with earlier outcomes of identical cement beneath identical situation.

Do ask to offer a normal lab set as much as your organization proprietor,

this will likely save an enormous losses at fraction of restore value.

Cement obtained in bulker➱

Loose cement dispatched in bulkers should not have the manufacturing particulars printed on it. You must confirm it by studying the main points supplied on dispatch challan.
Dispatch challan do point out the seals numbers that are printed on seals mounted at bulker openings after feeding cement in it.

Before opening the seals on all opening do confirm the numbers written on seal and challan are identical.

After verifying it do the identical course of which we use for inspecting bag cement.

Quality of Cement-How to check
Cement Transportation and feeding bulker

Preserving the pattern from every lot before Unloading➱

A Sample of cement as acquired must be protect in air tight bag or container with all particulars about that batch.

This may assist in fixing the dispute in future which can happen as a result of failure of concrete at undertaking

And in addition allow you to to blacklist the producer if he doesn’t settle for the failure.

Preserve pattern provides you with correct results of precise manufactured cement.

Failure in concrete might happen as a result of many potentialities equivalent to

Storage situation of cement at Construction site.
Batching situation for concrete.
Cube casting errors and so on.

Mistakes might occur at plant as a result of carelessness of any person (Chances are much less as a result of advance programs and automation at plants, however human could make errors too)

If you could have any query on it or if i had miss one thing please do reply i’ll right it.

This will assist engineers to do right checking of cement.

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Tubing-Tube- Materials, properties, efficiency

Tubing- Materials, properties, efficiency

Carbon and Alloy steel tube

1010

➱Low carbon range: .08/.13%
➱Good bending and flaring qualities, sometimes metallic element killed.
➱Good weld-ability and plasticity.
➱Relatively poor mach-inability.
➱Used for diesel oil injection lines; oil, fuel and hydraulic lines; condenser and warmth money changer tubes; heat-transfer tubes; lubrication equipment; shafting and bushings; thermocouple junction wells; and wide selection of mechanical applications wherever severe bending or forming needed.

1012➱

➱Low carbon range: .10-.15%
➱Produced from redraw that has been inside-surface conditioned to eliminate the likelihood of ID radial fissures and different defects.
➱Welding properties ar sensible.
➱Usually provided in Temper No. one (annealed) to allow severe fabrication like flaring, upsetting, and short-radius bending.
➱Used virtually completely for diesel oil injection lines.

1015➱

➱Low carbon mechanical steel tube often carried available by distributors attributable to its several applications.
➱Carbon range: .10-.20%.
➱Welding properties ar sensible with all strategies.
➱Flaring and bending qualities ar sensible within the tempered  condition.
➱Used for structural elements in industrial machinery, spacers, bushings, cylinder liners, punches, binder post, pinions, condenser and tuner shafts, magazine tubes in shotguns, gas valves, stitching machines, rifle and piece barrels.

1018➱

➱Generally provided in mechanical grade with carbon restricted to .15-.20% and element to .10-.30%.
➱Machinability is slightly higher than the “standard” 1015 material.
➱Welding properties ar glorious.
In Temper No. one tempered  condition, flaring and bending will be performed satisfactorily by traditional fabrication techniques.
➱Wide variety of mechanical applications the same as those listed for 1015.
➱Successfully used wherever a moderate quantity of machining is contemplated, however not requiring free machining grade like Leaded.

1020➱

➱Carbon range: .15/.25%
➱Used wherever slightly higher mechanical properties ar needed than will be obtained with 1015.
In the correct temper, this material has higher machinability than 1015.
➱May also be used for carburizing functions.
➱Used for record changerposts, chemical-projectile charge tubes, cable connectors, bushings and rollers, gun drill tubes, textile spindles, textile winder elements, hubs for wheel assemblies, and engine elements.

LEADED 1020➱

➱Excellent machining characteristics.
➱Carbon range: .15-25%.
➱Lead range: .15-35%.
➱The addition of lead makes it doable to chop quicker with heavier feeds, cut back decline the tool, and supply a higher end.
➱Interchangeable with 1020.
➱Preferred wherever savings from augmented machinability, lower tool wear, and finer end offset the upper material value.
➱Particularly helpful in screw machine operations, wherever high production necessities ar common.

1025➱

➱Where mechanical properties over those getable with 1020 ar needed, this material is usually counseled.
➱Carbon range: .22-.28%.
➱Good fastening qualities.
➱Used for framing structural elements, engine mounts, hard-hitting condensers and warmth exchangers, piston pins, readying instrumentality, ticker half, spacers, and housings.

1035➱

➱Carbon range: .32-.38%
➱Used wherever higher mechanical properties ar needed than with the lower carbon grades.
➱Within limits, mechanical properties will be improved over cold-drawn properties by heat treatment or a mix of warmth treatment and cold drawing.
➱Bearings and sleeves and bushings, fuse tubes, plating tank anodes, valve pushrods, housings, shanks for reamers, tire reparation tools, rock drilling instrumentality.

1045➱

➱Carbon range: .43-.50%
➱Used wherever higher mechanical properties ar needed than with the lower carbon grades.
➱Within limits, mechanical properties will be improved over cold-drawn properties by heat treatment or a mix of warmth treatment and cold drawing.
➱Bearings and sleeves and bushings, fuse tubes, plating tank anodes, valve pushrods, housings, shanks for reamers, tire reparation tools, rock drilling instrumentality.

1524➱

➱A high strength low alloy containing high metal.
➱Useful for prime pressure diesel oil injection systems.
5% Cr
➱A low carbon five-hitter chromium/.50% alloy steel.
➱Useful for warmth money changer tube.

4130➱

➱These low-alloy steels will be hardened by heat treatment.
➱In the tempered  condition afford sensible workability.
➱Can be equipped conditioned within surfaces.
➱Frequently used for craft structural elements. additionally for engine mounts, drone springs, water tubes, hard-hitting instrument lines, cable connectors, craft studs, bushings, radiolocation antennas and supports, drill shanks, and valve pushrods.

4132➱

➱These low-alloy steels will be hardened by heat treatment.
➱In the tempered  condition afford sensible workability.
➱Can be equipped conditioned within surfaces.
➱Frequently used for craft structural elements. additionally for engine mounts, drone springs, water tubes, hard-hitting instrument lines, cable connectors, craft studs, bushings, radiolocation antennas and supports, drill shanks, and valve pushrods.

8630➱

➱These low-alloy steels will be hardened by heat treatment.
In the toughened condition afford sensible workability.
➱Can be supplied with conditioned within surfaces.
➱Frequently used for craft structural elements. conjointly for engine mounts, drone springs, water tubes, aggressive instrument lines, cable connectors, craft studs, bushings, radio detection and ranging antennas and supports, drill shanks, and valve pushrods.

4140➱

➱Carbon range: .38/.43%.
➱Otherwise there’s very little distinction between 4140 and 4150.
➱However, 4150 is chosen once slightly higher mechanical properties square measure needed.
➱Golf club shafts, racquet handles, tamping rods, tufting needles, drill-shank conduit, key sockets, electrical connectors, and hand tools square measure typical applications.

4150➱

➱Carbon range: .48/.55%
➱Otherwise there’s very little distinction between 4140 and 4150.
➱However, 4150 is chosen once slightly higher mechanical properties square measure needed.
➱Golf club shafts, racquet handles, tamping rods, tufting needles, drill-shank conduit, key sockets, electrical connectors, and hand tools square measure typical applications.

4615➱

➱Carbon content is control to .13-.18% for optimum plasticity.
➱Made from redraw that has been specially conditioned to get rid of ID fissures and different defects.
➱Produced in accordance with current SAE customary for mechanical system conduit.
➱Annealed at end to provide a soft, ductile material. Used nearly completely for mechanical system conduit.

9260➱

➱Carbon range: .56/.64%
➱A high steel containing .75-1.00% atomic number 25 and one.80-2.20% element.
➱Possesses properties of toughness and fatigue resistance.
➱The analysis conjointly points to a cheap alloy.

52100➱

➱This low-alloy steel is employed once high hardness and resistance to wear and abrasion square measure needed.
➱Carbon content: .95-1.10%.
➱Proper heat treatment can improve, inside limits, the mechanical properties of cold-drawn condition.
➱Thread guides, nylon yarn guides, ball-bearing races, nozzles, gear and pinion elements, dental instruments, yarn carrier tubes, extrusion mandrels square measure among its applications.

STAINLESS STEEL CONDUIT➱

303 Se➱

➱An eighteen Cr-9% nickel nonhardenable alloy containing atomic number 34 and additional amounts of sulfur and phosphorus.
➱Most pronto machinable of all primary solid solution grades.
➱Properties on the point of those of kind 304, elongation somewhat lower.
➱Nonmagnetic in toughened condition.
➱Weldable by resistance strategies, fusion fastening not counseled. proof against scaling up to 1650°F.
➱For use wherever a free cutting material is required; offers high resistance to corrosion; assures sensible effect surface.
➱Typical applications: bushings, casters, shafts, rivots, valve and pump elements.

304, 304L➱

➱An eighteen Cr-10%, nickel low-carbon, corrosion and heat-resistant steel.
➱Nonmagnetic within the toughened temper.
➱Subject to damaging inorganic compound precipitation in 900°F to 1600°F vary.
➱Fully corrosion resistant in utterly toughened condition.
➱Excellent mechanical properties as low as -300°F.
➱Type 304L has exceptionally sensible fastening and fabrication properties and might be used rather than stable grades.
➱Extensively used for surgical instruments, food process instrumentation, potable coils, and textile machinery.
➱Other uses embody miniature bearings, camera elements, electrical device covers, ignition harness elements, heat exchangers, craft hydraulic lines.

What do you need for tubing?

305➱

➱A high-nickel variant of 18-8.
➱Behaves abundant constant as kind 304 in corrosion resistance, inorganic compound precipitation, and scale resistance.
➱Low magnetic permeableness (1.005 max.) even once gently cold worked.
➱Low work-hardening rate for severe forming.
➱For applications wherever severe forming is concerned.
➱Used for electrical instruments, beam tube anodes, and grid cups.

309S➱

➱Primarily a heat-resistant alloy containing twenty fifth Cr-12% nickel.
➱Good scaling resistance in continuous service to 2000°F, intermittent service to 1800°F.
➱Subject to inorganic compound precipitation in vary of 900-1600°F.
➱Corrosion resistance kind of like, however higher than, that of kind 304.
➱Very good creep strength and weldability.
➱Too robust for intensive machining.
➱Used extensively for sheath tubes on electrical heating components.
➱Also for warmth money handler and condenser conduit, craft heater elements, and hearth detection instrumentation components.

Why is tubing dangerous?

310S➱

➱This is a heat-resistant alloy containing twenty fifth Cr-20% nickel.
➱Mechanical and corrosion resistant properties rather kind of like, however higher than, those of kind 304.
➱Good for continuous service to 210°F-intermittent to 1900°F.
➱Nonmagnetic at temperature in toughened condition.
➱Excellent weldability.
➱Industrial chamber elements, reaction engine afterburners, thermometer protection elements, fuel lines, special passage lines.

316, 316L➱

➱A terrorist organization Cr-13% Ni-2 1/2% Mo alloy that gives the most effective corrosion resistance of the quality primary solid solution grades, particularly to H2SO3 compounds.
➱Highest creep strength of the three hundred Series.
➱Scale resistance is 1650°F scoop.
➱Type 316L could be a low-carbon variant and might be welded and heated within the vary 900-1600°F while not injury to corrosion resistance.
➱Excellent resistance to dyes, prescription drugs and method liquors.
➱Used conjointly for pipe springs and alternative instrument elements subject to severe corrosion.

317➱

➱A higher metallic element and Cr bearing primary solid solution chrome steel than kind 316.
➱Optimum corrosion resistance.
➱More proof against intergranular attack than kind 316.
➱Preferred wherever lightweight gage material is to be welded.
➱Suitable for applications requiring resistance to vitriol concentrations up to five at temperatures to 120°F.
➱Also wherever condensation of sulfur bearing gases happens.

What is the use of tube?

321➱

➱Type 321 is associate degree eighteen Cr-10% nickel atomic number 22 stable alloy
➱Designed to beat condition to inorganic compound precipitation and resultant intergranular corrosion.
➱Can be welded while not ulterior hardening.
➱Nonmagnetic within the toughened condition.
➱Hardenable solely by cold operating.
➱Approximate kind 304 in corrosion resistance.
➱Resist scaling up to 1600°F in continuous service, 1450°F in intermittent.
➱Types 321 and 347 have higher creep resistance than 304 (347 higher at higher temperatures).
➱Type 347 is extremely fine grained, limiting workability.
➱Aircraft hydraulic lines, exhaust collector rings, fuel lines, industrial and chemical instrument elements, capillary.

347➱

➱Type 347 is associate degree eighteen Cr-11% nickel Nb stable alloy
➱Designed to beat condition to inorganic compound precipitation and resultant intergranular corrosion.
➱Can be welded while not ulterior hardening.
➱Nonmagnetic within the toughened condition.
➱Hardenable solely by cold operating
➱Approximate kind 304 in corrosion resistance.
➱Resist scaling up to 1600°F in continuous service, 1450°F in intermittent.
➱Types 321 and 347 have higher creep resistance than 304 (347 higher at higher temperatures).
➱Type 347 is extremely fine grained, limiting workability.
➱Type 348 offers low-neutron cross section properties.
➱Type 347-Guided missile and rocket elements, readying instrumentation, pump and valve elements.
➱Type 348-Atomic energy applications wherever material either contains hot substance or is exposed thereto.

348➱

➱Type 348 is associate degree eighteen Cr-11% nickel Nb metal stable alloy
➱Designed to beat condition to inorganic compound precipitation and resultant intergranular corrosion.
➱Can be welded while not ulterior hardening.
➱Nonmagnetic within the toughened condition
➱Hardenable solely by cold operating.
➱Approximate kind 304 in corrosion resistance.
➱Resist scaling up to 1600°F in continuous service, 1450°F in intermittent.
➱Type 348 offers low-neutron cross section properties.
➱Type 348-Atomic energy applications wherever material either contains hot substance or is exposed thereto.

What is the difference between a pipe and tube?

21Cr-6Ni-9Mn➱

➱A changed two hundred series primary solid solution unblemished, out there solely in welded grade.
➱Developed permanently corrosion resistance and high strength.
➱High mechanical properties achieved as results of cold operating solely, as ar the three hundred series.
➱Excellent tensile and impact properties within the toughened condition as low as -423°F.
➱Approximately five hundredth of the nickel content of three hundred series unblemished steels are replaced by the redoubled metal content.
➱Having virtually doubly the strength-to-weight quantitative relation of 304, largest usage these days is for craft hydraulic lines.

408➱

➱403 is comparable to kind 410
➱Except that it includes tiny additions of nickel and Mo and might be hardened to illustrator C36-40 by ending or air cooling from 1750-1850oF. Not subject to inorganic compound precipitation, however low in impact properties at low temperatures.
➱Air hardening, they gift some problem in fastening.
➱Widely used where sensible spring properties ar required.
➱Excellent for pipe springs, medical instruments, and rotary engine elements.

410



Type 410 could be a basic hardenable alloy containing twelve-tone music metallic element,
Magnetic altogether conditions and may be hardened to Norman Rockwell C36-40 by extinction or air cooling from 1750-1850°F.
Not subject to inorganic compound precipitation, however low in impact properties at low temperatures.
Air hardening, they gift some issue in fastening.
Type 410 is least costly chrome steel.
Widely used where smart spring properties square measure required.
Excellent for pipe springs, medical instruments, and rotary engine components.

405



Ferritic steel not subject to considerable hardening through air cooling from high temperatures.
This tendency retards the knowledge of hardening cracks caused by fastening.
Practically a similar corrosion and oxidization resistance as sort 410.
Can be machined, drawn, spun and shaped delicately.
Used for applications wherever hardening upon cooling from high temperatures should be avoided.


Why must the ends of pipe be beveled before being welded?

416e



A hardenable, straight metal, low carbon (.15% max.) chrome steel containing either Se or sulfur to produce free machining properties.
Better machining properties than the solid solution 303 sorts, however lower corrosion resistance.
Developed particularly for automatic screw machine work.
Facilitates grinding, and is non seizing.


Concrete Properties It’s Types and Mix

430



Type 430 could be a straight 17 November metallic element alloy with corrosion and heat-resistant properties superior to those of sorts 410 and 420.
It is magnetic altogether tempers and nonhardenable.
The welded material is comparable, however has metal additional (.60% max.) to eliminate coarse grain welds of low plasticity.
Mechanical properties jibe those of soft-cast steel, machines higher than solid solution grades.
Widely used wherever corrosion resistance to the atmosphere, water, and foodstuffs is needed. Examples: dairy farm machinery, electrical appliances, oil burners, and chemical instrumentality.

430Ti



Type 430 could be a straight 17 November metallic element alloy with corrosion and heat-resistant properties superior to those of sorts 410 and 420.
It is magnetic altogether tempers and nonhardenable.
The welded material is comparable, however has metal additional (.60% max.) to eliminate coarse grain welds of low plasticity.
Mechanical properties jibe those of soft-cast steel.
Machines higher than solid solution grades.
Widely used wherever corrosion resistance to the atmosphere, water, and foodstuffs is needed. Examples: dairy farm machinery, electrical appliances, oil burners, and chemical instrumentality.

446



27% Cr-has the very best heat resistance of all ferritic unsullied steels.
A N additive is employed to forestall embrittlement through the 1200-1800°F vary and additionally to assist management grain size.
Resists scaling in continuous service to 1900-2100°F.
Excellent corrosion resistance to aqua fortis, targeted oil of vitriol, and most alkalies.
Shows smart resistance to sulfurous atmospheres at high temperatures.
Used wherever conduit is subjected to heat in oil and gas furnaces, for muffle tubes, fuel lines, steam boilers, chemical instrumentality, hearth detection instrumentality, and for capillary tube.

ALLOY 26-1



A unique twenty sixth Cr-1% Mo ferritic chrome steel.
Available in WELDRAWN grade solely at the moment.
Extremely clean alloy with terribly low carbon, N and alternative impurities.
Alloy is nickel-free, giving economic blessings as alternate for several applications wherever nickel-bearing unsullied grades square measure such that.
Excellent formability and corrosion resistance ought to build it fascinating material for applications within the chemical, organic compound, food process, pulp and paper fields.

N-55



An iron base alloy with wonderful oxidization resistance, smart plasticity.
Can be spun, rolled flanged and dish-shaped cold.
Can be machined, welded and brazed.
Has smart resistance to corrosion in bound media underneath each oxidizing and reducing conditions.
Recommended to be used in applications involving high stresses at temperatures to 1500°F and moderate stresses up to 2000°F.


What is Structural Engineering

17-7 pH



A chromium-nickel chrome steel containing more or less 1 Chronicles metallic element which will be hardened by a low-temperature precipitation hardening treatment.
Offers straightforward hardening, high strength, corrosion resistance akin to sorts 302 and 304, and high fatigue strength.
Can be welded by metal arc, gas-shielded arc and resistance fastening strategies.
Used extensively in craft and missiles yet as for valve and pump components.

16-6 pH



Precipitation hardening alloy thought of being a good replacement for Almar 362.
It is relatively higher in metal, carbon and nickel.
Its properties square measure like 17-7PH, except that it’s obtainable in seamless type for heavier wall applications.
Mechanical properties in each the treated and age hardened conditions square measure over Almar 362, and may be exaggerated considerably by cold operating before aging.
Outstanding characteristics: high strength, ductility, fabricability and exceptional corrosion resistance in numerous environments.
General corrosion resistance and strength seem higher than 410 and 430, and like, or higher than 304 and also the three hundred series of unsullied steels.
Used wherever conduit with high strength and smart corrosion resistance is required.
Immediate applications: instrumentation, high strength meat injection needles, gun drill shanks.

A-286



Precipitation hardening alloy.
Good strength to 1200°F.
Good oxidization resistance for intermittent service up to 1500°F.
Excellent corrosion resistance up to 1300°F against all atmospheres encountered in reaction-propulsion engine and turbo compressor applications.
Reasonably smart resistance to salt spray corrosion.
Used in rocket and reaction-propulsion engine applications wherever high combustible temperatures square measure encountered, and additionally for handling super-cooled fuels like LOX.
Also turbine fuel lines and craft mechanical and hydraulic conduit.

PRINCIPAL CHROME STEEL CONDUIT MERCHANDISE


Capillary conduit



Types 304, 316, 321, 347 and 446 unblemished. (Also 1010 carbon steel; Nickel-2000; Monel-400; and Alloy-600.)
ODs from .030 to .187 in., IDs from .004 in.
Has very clean and sleek ID.
Good fabricability.
Ductile.
High ID uniformity.
Coil lengths up to 3000 foot.

Super Pressure conduit



For pressures to a hundred,000 psi.
Normally made from varieties 304, 316, and 347 conduit.
Also accessible in 4130 steel.
Two types: single wall or composite wall.
Hydrostatically tested to sixty,000 psi once needed by client.
Sized from 1/8 to 3/4 in. OD.

Large OD, light-weight Wall conduit



Types 304, 321 chrome steel.
Sizes to a pair of in. OD, wall thicknesses .025 in. and lighter.
This thin-wall conduit is such as for stern applications wherever severe forming is needed, as in versatile hose, bellows, etc.

Aircraft Hydraulic conduit



Made in varieties 304, 321, 347 Alloy to rigid MILT and AMS specifications.
Guaranteed sleek and clean internal and external surfaces.
Furnished with certified check reports.
Available in each seamless and WELDRAWN forms in sizes from 3/16 to one 1/8 in. OD.
Every length clearly marked with our name, specification, analysis, heat range and size.
Types 21Cr-6Ni-9Mn and 3AI-2.5 Ti alloys are accessible for craft Hydraulic conduit Application.

Aircraft device conduit



Types 304, 304L, 310, 316, 316L, 321 and 347 unblemished.
Meets all industrial and military specifications.
Completely quality controlled with wall uniformity predominate.
Extra shut tolerances.
Precision surface inspected.
Offers fascinating brazing and fastening qualities.
Size range: 1/8 in. OD x .003 in. wall min. to 1/4 in. OD x .016 in. wall max.

Bellows/Flexible Hose conduit



Excellent plasticity to resist severe fabrication and continual flexing for convoluting grades.
Resistance to corrosion and high temperatures.
Freedom from carburization, dents and pick-ups.
Uniform wall thickness and temper.
Smooth surfaces to boost fatigue life.
Usually laid out in varieties 316, 321 and 347 unblemished, however additionally made in Monel Alloy four hundred, Alloy 600, Nickel 200, and alloy Alloy X-750.
ODs, 3/8 to one 1/8 in., wall thickness, .005 to .025 in.
Also created in composites of two,3 or additional plies of thin-wall conduit.

Needle conduit



Stainless steel kind 304.
Widely used for mechanical applications.
Offered in gages from half dozen through thirty three (see table).
Usually provided in lengths of two to twelve foot.


NICKEL AND alloy conduit


NICKEL two hundred (“A” Nickel)



Combines glorious mechanical properties with corrosion resistance that’s usually smart and is outstanding beneath several conditions of exposure.
Non-hard-enable by heat treatment; but strength and hardness could also be magnified by sold  operating.
Scale resistant in sulfur-free atmospheres to 1650°F.
Magnetic all told tempers and in temperatures to regarding 400°F.
Carbon content is .15% max.
Extensively utilized in physical science as cathodes in negatron tubes and in-tuned with reducing acids, foods, chemical process liquors, caustics, rayon, prescription drugs and plastics.
Also used once absolute purity of product should be assured.

NICKEL 201 (Low Carbon Nickel)



Has much constant chemical composition as Nickel two hundred, with one major exception-very low carbon content (.02% max.).
Excellent corrosion resistance-may be utilized in oxidizing temperatures to 1650°F.
Slightly less strength and lower work hardening rate than Nickel two hundred.
Recommended wherever shut radius bends and/or severe flanging or spinning is needed.
Also used for thermometer protection conduit in liquid salt bathtub furnaces.

NICKEL 211(“D” Nickel)



Generally similar in composition to Nickel two hundred, the foremost vital distinction being inclusion of four.5% atomic number 25 to interchange a like quantity of nickel.
Resists region and sulfur attack at elevated temperatures.
Mechanical strength, each at traditional and elevated temperatures, is somewhat larger than that of Nickel two hundred.
Used in constant style of applications as Nickel two hundred wherever larger resistance to sulfur oxidization and magnified mechanical properties area unit needed.NICKEL 270
High-purity grades of nickel exceptionally freed from nonmetal inclusions.
Offers low base hardness and smart plasticity.
Recrystallization temperatures for cold worked material area unit appreciably not up to those for Nickel 201.
Used extensively where Associate in Nursing exceptionally clean and very pure product is needed.
Present major application is for passive cathodes in receiving tubes and for structural parts in special-purpose vacuum tubes.

MONEL ALLOY four hundred (Monel)



Combines high strength, plasticity and wonderful resistance to corrosion; may be a all-purpose alloy.
Scale resistant in sulfur-free atmospheres to 1000°F.
Nonhardenable.
Magnetically attracted at temperature, however loses this characteristic at Curie point simply on top of temperature.
Used in chemical and process instrumentation, pulp and paper machinery, food process and packaging machinery, petroleum, organic compound and power-generating equipment.
Also in surgical and medical instruments, heating parts, magnet valves, and marine instrumentation.

MONEL ALLOY 404



Provided low magnetic permeableness.
Can be fictional without delay. Retains abundant of its strength at outgassing temperatures, and low magnetic permeableness isn’t considerably laid low with process and fabrication.
Well suited to be used in pickling systems handling sulphuric acid answer.
Also for vacuum capacitors and relays, ceramic to metal seals, and envelops for lepton tubes.

MONEL ALLOY K-500 (“K” Monel)



An age-hard-enable grade of Monel with a similar wonderful corrosion resistance, however having bigger strength and hardness.
Can be drawn, formed, upset swagged or otherwise cold worked within the tempered  condition.
Optimum properties is earned by heat treatment from the totally cold-worked tem Ideal for applications wherever strength, light-weight, and resistance to corrosion and wear ar necessary factors.
Widely used for drone springs, torsion tubes liquid level controllers, arbor rods, and sleeves and bushings in pumps and valves handling salt water.

ALLOY 600



A high nickel-chromium-iron alloy.
Outstanding in strength, corrosion resistance, and oxidization resistance at elevated temperatures up to 2150°F.
Can be joined by the same old attachment, brazing and attachment processes.
Extensively used for thermometer protection conduit, muffle tubes, jet and jet engine fuel lines, and instruments.
Also for food process instrumentation, dental and surgical instruments, and odontology appliances.

INCONEL ALLOY 601



Another of the nickel-iron-chromium alloys for top temperature service, exhibiting smart mechanical properties with wonderful resistance to thermal fatigue, distortion, and carburization.
Has exceptional ability to resist oxidization, each cyclic and static.
Uses embrace industrial heating, chemical industries, jet and rocket engines, and hot temperature instrumentation.

INCONEL ALOY 625



A nickel-chromium-iron alloy with atomic number 41 and atomic number 42 superimposed. Has high strength, corrosion and warmth resistance.
Shows wonderful resistance to oxidization as proven by cyclic oxidization tests that indicated total chemical compound penetrations of solely zero.0019 in. once one thousand time unit. at 1800°F and zero.0030 in. once 600 time unit. at 2000°F.
With the atomic number 41 and atomic number 42 additions it’s wonderful stress rupture properties to 1200°F and isn’t laid low with radiation embrittlement.
The higher hot strength of the alloy results from the solution strengthening of the nickel-chromium matrix by the addition of the atomic number 41 and atomic number 42.
Characteristics of alloy Alloy 625 indicate applications within the nuclear and craft fields.
Tubing has been provided for fuel part facing, rocket thrust chambers, and spray bars or nozzles for A/C engines.

INCONEL ALLOY 702



A high metal, low metal modification of alloy Alloy X-750 nickel-chromium-iron alloy.
Creep rupture strength at 1500°F for one thousand time unit. is 10,000 psi.
Offers wonderful oxidization resistance at temperatures to 2400°F.
Recommended for applications within the hot temperature vary wherever stresses ar comparatively low.
Has been used with success in high-temperature furnaces, for fuel part and warmth money changer conduit in nuclear reactors, and in craft and missiles.

ALLOY 718



One of the distinctive options of this alloy’s composition is that the addition of atomic number 41 to allow age hardening of this nickel-chromium-iron-molybdenum alloy.
It is so set aside from widespread nickel-chromium alloy series that ar age-hardened through the employment of metal and metal.
It has smart plasticity at 1200°F-1400°F and mechanical properties together with 1300°F.
Slow aging response permits heating and cooling throughout hardening while not danger of cracking.
Fracture toughness tests (with forms apart from tubing) at temperatures from -320°F to 1000°F indicate wonderful values.
Very satisfactory welds ar obtained victimization inert-arc techniques and issues related to attachment of age-hardenable alloys ar eliminated.
Applications embrace craft heat exchangers, versatile hose and bellows.

INONEL ALLOY X-750



High strength, corrosion resistance, and resistance to oxidization at elevated temperatures (1200-1500°F).
Creep rupture strength at 1500°F for one thousand time unit. is 18,000 psi.
Unusually robust at each normal and high temperatures and within the answer treated and aged condition.
Used for extremely stressed cannular components in corrosive and oxidizing atmospheres, together with braces in reaction engine afterburners, temperature probes, O-rings, bellows, sheaths for thermocouples, torsion tube assemblies, and rocket agent tubes.

ALLOY 800



A nickel-chromium-iron alloy with smart resistance to oxidation; retains its strength at elevated temperatures, has smart workability and attachment properties.
Superior to alloy Alloy 600 in resistance to sulfur, green rot, and liquified cyanide salts, comparable in resistance to oxidization and united neutral salts.
Used for Calrod units, chamber muffles, and warmth exchangers.

DURA NICKEL ALLOY 301 (Duranickel)



A wrought, age hardenable, nickel-aluminum alloy with wonderful resistance to corrosion, not to mention bigger strength and hardness than nickel offers at each space and elevated temperatures
Used for valves, pumps and warmth exchangers handling sulphuric acid sludges and different sulphuric acid solutions and different chemical applications wherever corrosion resistance is needed.


OTHER ALLOYS


WASP-ALLOY



Offers the most effective creep rupture strength of all Super Alloys which will be without delay fictional into conduit.
Can be heat-treated to get high strength needs.
Excellent corrosion resistance up to 1600°F against gaseous  atmospheres encountered in reaction engine operation and similar service applications.
Resistance to oxidization is extremely satisfactory through 1600°F in intermittent service; continuous service temperatures to 1900°F is sustained.
Applications embrace turbine engines and missile systems, reaction engine fuel nozzles, and device spray bars.
Also for different services requiring oxidization resistance at temperatures given on top of.

ALLOY L-605



Offers outstandingly smart corrosion resistance to most agents at normal temperatures.
Resistance to oxidization is nice for intermittent service to 1600°F and continuous service to 2000°F.
Creep rupture strength at 1500°F for one thousand time unit. is 18,000 psi.
Excellent resistance to the new corrosive atmospheres encountered in reaction engine operation.
Resistance to salt spray corrosion is nice.
Typical applications ar rotary engine blades, combustion chambers, device components, and rotary engine rings.
Also temperature probes, thermometer protection tubes, and instrument components and transfer lines within the chemical and organic compound field.

ALLOY 188



Cobalt-base Super Alloy; has 1000-hour stress rupture strength at 1200°F at twenty five,000 psi minimum stress together with resistance to progressive scaling (oxidation) and different kinds of corrosion.
Readily cold worked to extend strength and hardness, may be welded by most standard ways.
Potential uses embody heat instrumentation like thermometer sheaths, turbine and reaction-propulsion engine elements, and nuclear parts.

ALLOY C-276



Excellent corrosion resistance, particularly to metal chloride and cuprous chloride.
Also to wet halogen gas and salt and dioxide solutions.
Has wonderful heat strength.
Resistant to oxidizing and reducing atmospheres to 2000°F.
Primarily used wherever exceptional corrosion resistance and heat strength ar needed.
Typical ar the outer sheath for electrical hollow heating components, thermometer rakes, probes, photographic process instrumentation, and lubricating lines for chemical instrumentation.

ALLOY HX



Excellent high-temperature strength with chemical reaction resistance to 2200°F.
Creep rupture strength at 1500°F for a thousand hour. is 10,000 psi.
Unusual resistance to oxidizing, reducing and neutral atmospheres.
Easily shaped and welded.
Used in the industry thanks to its corrosion resistance and high strength and for jet craft and missile elements and parts.
Also for fuel components in nuclear reactors, thermocouples, metal spray nozzle sleeves, protective cover for ceramic-insulated thermocouples and electrical heating components.

80-20 ALLOY



Combines high thermal ANd mechanical properties with ohmic resistance to an unexceeded degree.
Withstands temperatures to 2100°F for long periods.
Highly immune to corrosion.
Nonmagnetic.
Used for reaction-propulsion engine igniter plugs, thermocouples, instrument elements, special condensers, heat exchangers, and resistance heaters.
30% copper-base alloy
Outstanding for service wherever corrosion and erosion ar encountered.
Higher hardness, tensile and yield strength, and plasticity than the ten alloy offers.
Retains a lot of of its short-time strength and plasticity up to concerning 700°F.
Strength and plasticity increase with falling temperature to concerning -320°F.
Widely utilized in applications requiring exceptional corrosion resistance.

NI-SPAN C ALLOY 902 (Ni-Span C)



Heat treatable; designed primarily to get a continuing modulus of snap during a helpful temperature vary of -50°F to 150°F.
Outstanding modulus management and high strength combined with low drift in mechanical physical phenomenon.
Offers corrosion resistance superior to it of nonstainless steel.
Excellent for drone springs, instrument bellows, and magnetostriction devices.
Also utilized in pressure sensing components of transducers, potentiometers, accelerometers and gyroscopes.

Nickel-Iron Alloy



Fundamentally fitted to structural elements.
Strong, tough, ductile. helpful degree of corrosion resistance.
Magnetic at temperatures below their curie points and nonmagnetic on top of them
Cannot be hardened by heat treatment, however may be strong by cold operating.

36% Nickel-Iron Alloy



Used for bimetallic or composite tube in regulator controls, thermometers, measure and astronomical instruments.
Also air-conditioning-control instruments, strain gages, and features transporting liquid gas.

42% Nickel-Iron Alloy



For protection to glass. it’s well-tried helpful as a regulator metal for higher temperatures.
It has been utilized extensively within the construction of vacuum tubes, lamps, terminal caps, condenser elements, and electronically controlled switches.

52% Nickel-Iron Alloy



Has more or less a similar constant of enlargement as many business glasses furthermore because the forsterite kind ceramics.
It is conjointly one amongst the popular alloys for sensitive magnetic applications and for regulator work. Its high magnetic porousness at each low and high flux densities could be a valuable property.

4 Alloy



Nickel-chromium-iron.
Expansion constant ideal certainly soft glasses.
Widely used as an inside seal.
Thermal electrical electrical resistance is somewhat high, and current-carrying capability is proscribed.
Provides a vacuum tight and strainfree seal.

Alloy 29-17 (Kovar)



A nickel-cobalt vacuum melted  flow enlargement alloy used for creating tight seals with tougher glass glasses and ceramic materials.
It has found use in electronic applications like diodes and integrated circuits.

PRINCIPAL NICKEL AND NICKEL ALLOY TUBING PRODUCTS


Bourdon conduit



Ni-Span C Alloy 902, Monel Alloy K-500 and metal Alloy X-750 ar the foremost unremarkably such as for pipe tubes.
Superior offers these grades in ODs from one/8 through 1 1/8 in. with walls to .125 in. maximum; on top of 5/8 in., most wall is .035 in.

Thermo-couple Protection conduit



Generally laid out in Alloy-600, Monel Alloy four hundred, half-hour copper-base alloy, Nickel-200, and alloy C-276.
Sizes most typically used fall inside the vary of 1/8 to 1/2 in. OD with wall thicknesses.


Super Alloy conduit


Alloys HX, 188 C-276, L-605, 625, 702, 718, X-750, A-286, and Waspaloy ar the nickel alloys usually classified by the trade as “Super Alloys”.

Tubine for physics



36% Nickel-Iron Alloy minimizes the matter of thermal enlargement and contraction in lines handling N
Nickel two hundred and Monel Alloy four hundred ar terribly effective in handling liquid halogen
Alloy 600, metal Alloy X-750, Monel Alloy K-500 and alternative high-nickel alloys supply wonderful properties at low temperatures.

COPPER BASE ALLOYS


30% copper-base alloy



This nickel-copper (30%-70%) alloy was primarily developed to resist cavitation by steam and air mixtures in condensers.
It is extremely immune to many sorts of atmospheres and alkalies.
Has the lastingness of 70-30 brass and is well fancied. Used for economical fine-wire connectors, electrical contacts, rod ferules and guides, and gas action columns.

Beryllium Copper



This cold-drawn material contains one.80-2.00% Be, and nickel or atomic number 27 or each, .20% min.
Its greatest advantage is that it will be shaped whereas within the tempered  condition and, once heat treatment, develops high strength and hardness (C34-42).
Has a high strength-to-electrical-conductivity magnitude relation, wonderful spring stability, resistance to fatigue, wear and corrosion resistance.
Used for pipe tubes, electrical connectors, pc card sorting rolls.

Berylco 33-25



A free-machining Be copper alloy that retains all the physical and mechanical properties of Be copper, as well as fabricability, exceptional stability as a spring material, and wonderful resistance to fatigue, wear, and corrosion.
Where machining time is a vital issue, Berylco 33-25 offers a set advantage over alternative Be copper alloys.
Should cut back machining time by four-hundredth or a lot of.

REACTIVE AND REFRACTORY METAL CONDUIT


Unalloyed atomic number 22 A-40 conduit



The outstanding benefits of sunshine weight and extremely sensible corrosion resistance create this reactive metal ideal for industrial heat exchangers.

Titanium Alloy 3AI-2.5V



A high strength atomic number 22 alloy exhibiting wonderful malleability and cold workability.
Useful wherever strength-to-weight magnitude relation is very important.
Numerous applications within the region trade.

Titanium Alloy 6AI-4V



A high strength atomic number 22 alloy of high alpha-lean beta composition.
High strength-to-weight magnitude relation, wonderful corrosion resistance, sensible fatigue properties, and superior fracture toughness.
Readily machinable and weldable.
Particularly helpful in applications like structural material in aircraft/aerospace trade.
High resistance to brine corrosion.

Columbium and atomic number 41 Alloys



These refractory materials ar utilized in heat structural applications within the missile/aerospace trade, likewise as for fuel component protection functions.
The 1% Zirconium-Columbium alloy is accessible.

Tantalum and atomic number 73 Alloys



High temperature and corrosion resistance.
Ideal for thermocouple junction protection conduit use.
Also wonderful for handling chemical compounds of atomic number 17, chlorides, hydrochloric and azotic acids.
Tantalum alloy conduit is created on a development basis.

Molybdenum and Mo Alloys



Produced on a development basis in an exceedingly restricted vary of sizes and lengths.


ALLOY conduit thought-about FOR convenience BY REQUEST

Titanium Alloy 15-3



A beta atomic number 22 alloy exhibiting a strength-to-weight magnitude relation 2 hundredth over the quality alloy, cold-worked stress-relieved 3AI-2.5V atomic number 22 alloy.
The present elongations ar comparable.
This beta alloy is additionally abundant less notch sensitive than 3AI-2.5V atomic number 22 alloy.
Possible region applications like craft hydraulic line and engine conduit.
The alloy’s strength could also be accrued up to five hundredth by an easy age hardening treatment following fabrication.

Alloy 29-4C



A high purity ferritic stainless-steel having wonderful roughness and crevice corrosion resistance in high chloride environments like brine.
It usually has superior crevice corrosion resistance to alternative commercially out there unstained steels and represents a balance between corrosion resistance and economy.

Alloy 690



A solid solution-ed reinforced nickel base alloy having wonderful corrosion resistance to a broad vary of environments, each at close and elevated temperatures.

Alloy 2205



A duplex unstained having a fine grained micro structure consisting of regarding five hundredth solid solution in an exceedingly primary solid solution matrix.
The alloy is superior to 316 and 317 in several things and has double the yield strength of 304.

Inconel 617



A nickel-chromium-cobalt-moly alloy exhibiting wonderful heat strength and oxidization resistance.
Developed to be used in craft engines, thermocouple junction protection tubes and heater tubes.

Incoloy 825



A nickel-iron-chromium alloy containing Mo and copper to form it terribly immune to reducing environments like element or oxyacid.
It is conjointly immune to chloride stress corrosion.

1524 Steel



A high strength low alloy containing high Mn.
Useful for prime pressure fuel injection systems.

5% metallic element Steel



A low carbon five-hitter chromium/.50% alloy steel helpful for warmth money changer conduit.

9260 Steel



A high steel containing one.00% Mn and a couple of.00% atomic number 14.
It possesses properties of toughness and fatigue resistance.
The analysis conjointly points to a cost-effective alloy.

Ferralium



A twin section ferritic-austenitic stainless-steel which mixes high mechanical strength and malleability with outstanding corrosion resistance, particularly to reducing acids.
It is kind of like our alternative twin section alloy 2205.

29-17 (Kovar)



A nickel-cobalt vacuum dissolved flow enlargement alloy used for creating tight seals with more durable Pyrex glasses and ceramic materials.
It has found use in electronic applications like diodes and integrated circuits.




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Concrete- Properties , Types and Mix

Concrete- Properties , Types and Mix
Concrete

Properties of Concrete

Segregation(parts or substances disperses)  in concrete is because of particle segregation in concrete purposes and makes use of, through which particulate solids tends to get segregated by high quality or property of variations within the measurement, density, form and different properties of particles of which they’re composed.The concrete stoop check measures the consistency of contemporary concrete earlier than it units.

The workability check(or stoop check) carried out to test the workability(the property of concrete to ease of compaction, transportation and pouring) of freshly made concrete or concrete combine. It may also be used as an indicator of an improperly combined batch.Simply outlined, stoop is a measure of the consistency of contemporary concrete.

The stoop check or check of workability is a quite simple and straightforward check. it the apparatuses The stoop cone is a proper round cone that’s 12 inches excessive. The base of the cone is eight inches in diameter and the highest of the cone is four inches in diameter.Bleeding in contemporary concrete refers back to the course of the place free water within the combine comes upward to the floor as a result of settlement of heavier stable particles comparable to cement and water. Some bleeding is regular whereas some extreme bleeding can create issues on concrete.

Make certain that the chilly climate concrete has been cured and don’t allow hardened concrete to dry out.

Keep ice from forming – Once ice is fashioned, the hydration stops and the power growth is intensively impaired. Fresh concrete frozen through the preliminary 24 hours can lose 50% of its power of 28 day power!

What Should be salary of engineers

Pouring Concrete vs Pouring Rain

If it rains in the course of the interval when the concrete is contemporary (about 2-Four hours after mixing), the entire floor ought to be protected(no rain drops ought to enter) from the rain. If the ending course of was just lately achieved, rainwater could not trigger any injury so long as it has not labored into the floor even and the slab is out of contact.

What is soil exploration in Civil Engineering

Grades of concrete

Concrete is acknowledged and designed  by its grades which is designed as M15, M20 and many others. by which letter M represents the concrete combine and quantity 15, 20 represents the required compressive energy (fck) of 150mm dice at 28 days  in N/mm2.

What is concrete explain?


What is concrete used for?

Concrete Honeycomb



Water cure:-Curing

The most important strategies of  curing of concrete is flooded, ponded, or mist sprayed. These are the simplest curing technique and strategies for the stopping combine from water evaporation. Make positive sufficient time is given to concrete for curing.

Water retaining methods:

Use coverings corresponding to sand, canvas, burlap, or straw which might be stored constantly moist.Other reactive penetrating sealers (silanes and siloxanes) and most high-performance coatings, corresponding to epoxies and urethanes, be certain these to be utilized solely after the concrete is absolutely cured (usually 28 days). Almost all sealers can used after the concrete hag achieved the age of  28 days.

The typical vary Taken is in between the vary of  9.5 mm and 37.5 mm in diameter. – Fine aggregates are normally sand or crushed stone that are beneath the vary 9.55 mm in diameter. Normally essentially the most usable widespread measurement of mixture which is utilized in development is 20 mm. 40 mm measurement of mixture is widespread in mass concrete.

The water–cement ratio is the ratio of the burden of water to the burden of cement used within the combine. A decrease water cement ratio outcomes the upper power and sturdiness, however it might trigger the combo troublesome to work with and type.

Workability might be resolved with the usage of plasticizers or super-plasticizers.Superplasticizers, also called excessive vary water reducers, are chemical admixtures used the place well-dispersed particle suspension is required.

The addition of superplasticizer within the truck throughout transit is a reasonably new improvement inside the business.A concrete combination ratio of 1 half cement, three components sand, and three components mixture will produce a  mixture of practically 3000 psi. the Mixing of water with the cement, sand, and stone will create a paste which can bind the components collectively till the combo is hardened.

Concrete honeycombing is normally brought on by just a few widespread components, together with: An absence of integrity on the perimeter type boards on the time the concrete is being poured.the uneven or not in correct ratio of cement to water ratio that outcomes poor workability concrete. Poor consolidation practices or inefficient technique of vibration.

Concrete- Properties , Types and Mix
Concrete honey combing


Concrete Mix Ratio

In order to fight this downside, footings are positioned 6 inches beneath the frost line. The frost line is the utmost depth the place the bottom stage will get freeze within the winter.  If the kinds are eliminated too quickly, the concrete can start to sag, crack and collapse, particularly if situations like temperature affected its energy.

The fineness of fantastic mixture (cement) is measured by sieving it on commonplace sieves. The proportion of cement of which the grain sizes are bigger than the desired mesh dimension is thus decided.Water–cement ratio.

Workability may be resolved with using plasticizers or super-plasticizers.Empty the combo right into a mortar tub or wheelbarrow and kind a despair in the course of the combo. Measure the really useful and required amount of water (every 80-pound bag of concrete combine would require about Three quarts of water). it will likely be the Pour roughly of  2/Three of the water into the despair.

If utilizing liquid cement shade, add to the blending water.Allow Proper Time to Water Cure. when the concrete is positioned or poured, the energy of concrete will increase in a short time in a interval of 3-7 days.

Concrete which is moist cured for 7 days is about 50% stronger than uncured concrete.Mortar is used to carry constructing supplies equivalent to brick or stone collectively. It is shaped of or composed of a thick combination of the components water, sand, and cement.The water to cement ratio is greater in mortar than in concrete in an effort to kind its bonding aspect.


Types of concrete

Workability may be resolved with using plasticizers or super-plasticizers.Sand is the most typical mixture additive to cement however it’s not the one choice. You can use many different aggregates together with crushed stone, gravel and chunks of previous concrete.

You can combine cement with out sand if you happen to use different aggregates.Cement is made by heating powdered limestone with clay. Cement is a element in mortar and concrete: mortar, used to bind or create bond between joints of  bricks collectively, is ready by including cement in sand and water combine.

Concrete is made by mixing cement with sand, water and mixture (crushed rock).Lime is used extensively for wastewater therapy with ferrous sulfate. The rocks and minerals from which these supplies are produced or generated, usually  limestone and chalk, are composed of calcium carbonate primarily.

Materials that has the sufficient amount of calcium compounds, silica, alumina and iron oxide are crushed,  screened and positioned in a rotating cement manufacturing kiln. Ingredients used on this course of are usually supplies akin to limestone, sandstone, marl, shale, iron, clay, and fly ash.Empty the combination right into a mortar tub or wheelbarrow and type a melancholy in the midst of the combination.

If utilizing liquid cement colour, add to the blending water.On common, the price of putting in a cement slab can run between $three and $12 per sq. foot of area. However, that quantity could also be larger or decrease relying on whether or not the terrain wants in depth work beforehand, the concrete thickness is uncommon or the house owner helped put together the positioning.


What is structural Engineering

CONCRETE MIXING RATIOS


Another “old rule of thumb” of blending concrete ingedients is 1 half cement : 2 half sand : three half gravel by quantity. Mix correctly(in order to get uniform combine) the dry substances and slowly add water into the dry combine till the concrete is workable.

This combination might must be modified relying on the mixture used to supply a concrete of the fitting workability.Concrete is a heterogeneous (composite) materials consisting of cement, water, advantageous aggregates and coarse aggregates.Otherwise it’s a heterogeneous materials.

Cement could also be known as a homogeneous materials. But concrete is just not.Concrete Language. Abstract phrases denotes the intangible qualities, virtues, concepts, and ideas. These phrases reveals issues we all know solely by our intellectul thoughts, like “truth,” “honor,” “kindness,.” Concrete phrases check with tangible, qualities, virtues , properties or traits, issues we all know via our senses or data.

The Concrete is usually ready with these three primary elements: water, combination (rock, sand, or gravel) and cement. Cement, acts as a binding agent when it’s combined with water and aggregates.

The water causes the hardening and setting  of concrete combine via a course of known as hydration of cement. Hydration is a chemical response between cement,water and combination through which the foremost compounds in cement type chemical bonds with water molecules and turn out to be hydrates or hydration merchandise.

The particles in a mix are nonetheless composed of components and compounds, however they don’t seem to be all equivalent.Cement is a mix as a result of it’s composed of various kinds of compound particles.


STRUCTURAL ENGINEERING

STRUCTURAL ENGINEERING

 


STRUCTURAL ENGINEERING


Problem-Solving Through Creative Approach in Structural Engineering
Structural Damage Assessments

In forensics, the knowledge and experience of all of us of structures plays a key role to understand how  environmental events and weather, building usage and gravity can affect the life of a structural part or the whole structure.

Experience and knowledge of structural engineering has reflected and shown also to us how construction and installation defects, deferred maintenance and substandard materials can result in any loss or damage. 

What is structural engineering exactly?

Building defects and deficiencies become more evident after weather and environmental events, such as flooding, tornados, and hurricanes. For example, wooden structural parts that has been exposed to long-term or repeated moisture contact may be structurally damaged from rot, microbial growth, potentially resulting in failure during what would otherwise be considered a non-damaging event.

Every region of the United States has its own geographical and climatic distinctions. The expert professionals at Stephens Engineering are well informed of the unique variables in construction and structural stability in your specific region.

Our professionals are knowledgeable in the building practices and process that results in sound construction and can investigate and identify construction defects readily. From years of experience, we understand the complex factors that need to come together to achieve a sound structure. We are uniquely qualified to complete structural-related damage investigations.

What is the work of structural engineering?

What are the basic structural elements?

You must Read about The Salary of Engineer

Flood Damage Investigations

Flood damage is a serious problem…one that needs to be addressed quickly and accurately. The experts at Stephens Engineering are experienced in investigating various types of structural- and foundation-related damage due to flooding. Flood damage investigations typically involve observation and assessment of the various building components
(foundations, pilings, framing, roofing and claddings, and inundated materials) that may have been removed, displaced or structurally compromised by the flood event.
Whether the damage is solely flood related or we are deciphering between flood vs. wind damage, we are prepared to evaluate the root cause and timeline of the damage.

What are the 3 types of structures?

What are examples of structure?

Building construction and process

Structural Collapse Examinations

Whether due to design or construction deficiencies, extreme wind loads from tornados and hurricanes, storm surge, earthquakes, tree or vehicle impacts, soil movement, material defects, decay/corrosion, or maintenance deficiencies, the Stephens Engineering experts can determine the proximate cause of the structural failure or collapse.
We primarily focus on the cause and extent of the damage and provide repair recommendations, if necessary. Each report is illustrated with photographs. Our report will locate and describe the claimed and unclaimed damage on the property and articulate a precise opinion based solely on the discovered evidence and research.


Construction Defects

The International Risk Management Institute (IRMI) defines a construction defect as “a deficiency in the design or construction of a building or structure resulting from a failure to design or construct in a reasonably workmanlike manner, and/or in accordance with a buyer’s reasonable expectation.” Deficiencies can result from design errors and/or omissions, the installation of defective, damaged, and/or inferior products or materials, and/or substandard workmanship.
Construction defects can cause physical damage to people or property or financial losses in the form of loss of use or value and/or increased expenses.


Roofing Damage

Stephens Engineering performs roofing damage assessments on residential and commercial buildings for all types of roofing (asphalt shingles, modified bitumen, roll roofing, metal, clay and concrete tile, EPDM, TPO, built-up roofing, and more).
From low-sloped roofs to elevated high-pitched roofs, our engineers can identify the difference between weather-related damage (hail and wind), installation defects, animal or man-made damage, new vs. old damage, or age-related deterioration.

Real Estate Foundation Inspections

Stephens Engineering Consultants, Inc. provides commercial and residential foundation inspections and assessments. Having a foundation inspection by an experienced structural engineer with help you to understand the real causes behind the damage and provide recommendations for remediation.
We know that a foundation inspection needs to be completed with great care and attention. For this reason, our foundation inspection service goes beyond the common “Level A” offered by home inspectors. In addition to a thorough visual inspection of the structure and foundation, our “Level B” foundation inspection includes:
  • A thorough, detailed foundation assessment that is accompanied by a computer-generated sketch of your foundation;
  • Interior observations of your interior floor plan, walls, and other areas;
  • Exterior drainage and damage inspection;
  • Review of the exterior landscaping and vegetative growth as it pertains to foundation performance;
  • A clear conclusion of our findings that is supported by quality photographs;
  • Engineering recommendations, if necessary, to assist with decisions concerning the best course of action.

salary of engineer-Best Salary Engineering job

salary of engineer-Best Salary Engineering job

Which engineering has highest salary ?


What are the 6 types of engineers?


Types of highly paid engineering job 

There is a common that it requires 4 lines of work to be balanced for the well existence of the world. They are namely; Medicine, Arts, Law and Engineering. The closer your profession to these categories, the more you will earn and the more important you will be to the society; period. When it comes to engineering, you can comfortable say that every other thing that you utilize on daily basis are invented by engineering. That’s why you should consider doing engineering.

Here are 7 careers under engineering.


1-Building engineering



Have you always had a love for building skyscrapers? Does your definition of aesthetic includes a lot of buildings? If so, building engineering or high riser engineering is the profession for you. Being the textbook interpretation of the concept engineers, you will be able to earn a fortune if you were a committed person in this line of work.

What do building services engineers do?


What do you call a building engineer?

Still there is huge opportunity in the field of building engineering, as In the developing countries a lot of infrastructural development has to take place,

What is a building engineer salary?

The Salary of Building Engineers is Different in Various countries if we talk about united states the average salary for building engineers $70780 as of June 30, 2020. the salary vary between the rang of $61000 to $83300 per year,The range of salary whatever a building engineer may be receiving depends on many factors such as educational qualification, certifications, additional skills, number of years of experience he have etc.

How much does a building engineer make an hour?


What qualifications do you need to be a building services engineer?

And if we talk about the salary of building engineers in India, the salary is maximum 40 k INR per month in starting if he has degree in engineering from any reputed college of IIT, if he has diploma in engineering then the maximum salary is not more than 22 K INR per month, salary vary in the range of 30 to 40 K INR per month, for Degree holders,

salary of engineer-Best Salary Engineering job

2-Highway engineering


A country’s infrastructural facilities decide the economic growth and existence of the country. Roads of all types are one such component. Being well, qualified in this line of work will immensely be beneficial since the world doesn’t stop developing itself.

Why do we need to study highway engineering?

There is a lot of scope of highways in developing countries like India,Even Developed countries also are spreading the network of highways continuously for better connectivity and development,

The Salary of highway Engineers is Different in Various countries if we talk about united states the average salary for highway engineers $70500 per year as of June 30, 2020. the salary vary between the rang of $60000 to $82500 per year ,The range of salary whatever a highway engineer may be receiving depends on many factors such as educational qualification, certifications, additional skills, number of years of experience he have etc.

What do highway engineers do?

And if we talk about the salary of highway engineers in India, the salary is maximum 39 K INR in starting if he has degree in engineering from any reputed college of IIT, if he has diploma in engineering then the maximum salary is not more than 21 K INR per month, salary vary in the range of 35 to 40 K INR per month, for Degree holders,

salary of engineer-Best Salary Engineering job

3-Hydraulic engineering

Just like how the majority of our body is made out of water, the world cannot live without water. That’s why hydraulic engineering is a line of work where you can earn a lot while helping the development of the country. This involves the designing and maintenance of dams and things like that; they are quite interesting to learn.

What is the study of hydraulics?


Why is hydraulic engineering important?

The Average salary for hydraulic engineers is near about $ 55000, it ranges in between $53000 to $ 57000, and the minimum salary and an inexperienced individual is approx $ 37000, while the highest salary in approx $ 109000, The salary Varies depending on various factors such as described above.


What do you call a water engineer?


In The current times there is a big issue of conserving the water, That is why there is great opportunity in this field for the professionals, 


An aptitude for engineering and a vision that would help in effective management of water resources would be the most essential skills. Good business acumen, excellent project management skills, ability to work under pressure, good planning and organizing skills are some of the other qualities which will be of great help. He/she should be able to demonstrate a strong sense of responsibility, commitment, and dedication.


The most useful ans essential skill for a hydraulic engineer is an greater aptitude for engineering and a great vision, project management skills, being able to work under extreme pressure, better planning skill, better organizing skill and ability to understand all the technical and practical terms, these are the skills which helps an individual for better career growth, 

salary of engineer-Best Salary Engineering job

4-Mechanical engineering



Mechanical engineering is yet another field that has many sub branches in it. This is where you would learn about all the turbines, engines and everything where there cogs and whatnot. If you are into detailed mechanisms of vehicles, and heavy machinery, this is an amazing field to get yourself into.

Is mechanical engineering a stressful job?

There are many streams and function in mechanical engineering such as Design, construction, study, development, production, testing and inventing mechanical tools, engines, Machines, thermal sensors and devices, for fulfilling the human needs.

What the mechanical engineers do?


Is Mechanical Engineering a good career?

There are many branches in mechanical engineering such as automobile engineering, Power plant engineering, manufacturing engineering etc.

What are the types of mechanical engineering?

Mechanical engineers has to work in offices generally but many times they have to go for visit the sites also to check and solve the issue if any occurs,In Construction industries the mechanical engineers has to spent half time on sites to maintain the productivity and better utilization of equipment, working on sites.

Generally mechanical engineers need Bachelor’s degree in mechanical engineering stream or mechanical automobile engineering.

There is a anticipated statics that the growth in mechanical engineering will be 9 % in the period of 2016 to 2026 according to Bureau of Labor statistics.

According to Bureau of Labor statistics reports the income of Mechanical engineers in mid 2016 was $ 84195 Per year, in current time the salary of Mechanical engineers is minimum $ 700000 Per year.


5-Mechatronic engineering



This line of work is a combination of electronic and mechanical engineering in the right amounts. If you have found yourself to be interested in robotics and even nanotechnology, this is the best field for you. You just could end up as the first engineer to construct a Transformer robot!

What mechatronic engineers do?


What should a mechatronics engineer know?

Mechatronics Engineers or Specialist have to work with designing control systems, Control systems for bottling or packaging of edible products, Massive industrial robots, prototype developments etc.

Is Mechatronics Engineering in demand?


Is Mechatronics Engineering a good career?

 Mechatronics Specialist have different job titles as following.

➱Service Engineer.
➱Instrumentation Engineer.
➱Systems Engineer.
➱Data Logging Engineer.
➱Software Engineer.
➱Control System Engineer.
➱Automobile Engineer.
➱Project engineer.

What are the subjects in mechatronics?

What is Mechatronics Engineering salary?

The Average Salary of Mechatronics Specialist is Approx $ 88800 Per year, and The Highest Salary is Approx $ 103380 Pers Year, This Data is As per the site Recruiter.

6-Electrical engineering



The world is in dark without electricity. In fact, electricity is what keeps the world running. The demand for electrical engineers will simply never go down since every day new projects start and every day huge power plants needs to be looked after.

The Salary of Electrical Engineers is also As per Mechanical engineers, Which Depends on Experience, Qualification, Skills, Etc.

What is the average starting salary for an electrical engineer ?


What is the highest salary for a electrical engineer?


Is Electrical Engineering a good career?


What skills do electrical engineers need?


7-Automobile engineering

If you’re a motor head, choosing this side of engineering will help you to educate yourself on the things you love. The demand for automobile engineers will always be high because the world of cars doesn’t die ever, so will your source of growing income.

Which course is best for automobile engineering?

What is the scope of automobile engineering?

Please click here for more updates

Pile Load test

Pile Load test

PILE LOAD TEST


INTRODUCTION➱

Something relevant for onshore and coastal areas where the possibility of load testing is feasible whereas for offshore conditions full-scale load testing is not feasible because of several constraints In any case to understand what involves such load test will be very useful so that you can see what alternatives can be worked out for offshore conditions.

But in the near shore around less than 20-25 meters we have done pile Load testing but quite cumbersome quite expensive and time-consuming So the pile Load test if you look at the design of foundation you know there has always been a debate because of the uncertainty associated with the soil parameters.

Always it is understood that design is verified by testing to full scale at the side of the final construction If you look at many of the international course obviously they state that in the engineering based design is not hundred percent sure.

So if you go back to British course or European course including Indian course specially for pile foundation, you will see that every pile needs to be tested to its capacity ,

So if you have seen in a construction site several hundred piles testing every one of them becomes you know elaborate as well expensive time-consuming it puts the whole project in a different schedule of construction activities,

So you select critical piles or piles that may represent actual site conditions So among hundred number of piles may select say 2 piles or 3 piles which may represent actually the site conditions ,So normally most of the modern-day projects we take about 3 to 5 percent of the piles,

That means if you have hundred piles you do the testing of 5 piles So you select them in randomly to distribute all around the site in such a way that you can extract information from this pile testing so that you can represent them in the design process,

But by doing that what you are actually going to do is you take this so-called test parameters and then that calculate and go back to the design revisit the design and adjust the design parameters to suit the tested pile information,

So if the tested file is giving the design or the failure load is lower than the design load means your design parameters what you have used in your calculations are on a higher side or vice versa So you can go back and then adjust the parameters until that you get the design capacity versus failure,

Load is almost close by so this adjustment is even now many of the projects we try to do this so that in the future installation become almost reasonably correct So that means this testing has to be done up front before the construction starts so that is the idea behind pile load testing,

That means you get a comfortable level of confidence which is very essential for foundation system,because you cannot have an uncertainty on a foundation for structure which may actually pose a big threat So the pile Load test has been there for several decades for onshore and offshore projects of near coastal areas,Several kinds I would say So since,

What is the purpose of pile load test?

PROCEDURE OF PILE LOAD TEST➱

Now you see the procedure how we want to start the project with low testing we want to do the load tasting up front before the actual construction starts so you can say sacrificial testing that means once you do the testing of this piles the piles will never be able to use it because you already have failed the pile to ultimate load capacity that means you have a different category of testing

Or you can actually test the same pile which you want to use it as a part of the structure that means you cannot fail the pile but you can actually apply the loading until the load that it may get during its service You know so you can see here now planning is required what type of testing is planned for that particular site whether you want to do a full-scale failure to load test or you want to a working load test,

The test that may actually take you to the level of working load and stop then you actually construct the structural system on top of it So this pile Load test is quite useful in a sense so we will look at various test and the procedures available for us So we will be looking at both horizontal load test and vertical load test,

You know we have specially the coastal areas and the berthing structures and offshore structures we have considered amount of horizontal load compared to onshore structures And then we will look at some of the testing some special testing by which you could actually get the similar information,

But that kind of empirical method you do some testing and extract the information and prorate it to obtain the axial failure load which nowadays seems to be very economical and is quick specially the dynamic testing and some of these are commonly used,

Pile Load test

So if you select 5 percent of the piles for testing using gravity method the remaining 95 percent you know still uncertainty exist because if you look at a site your construction site say 1 kilometre by half kilo meter wide industrial construction and you select only 5 remaining 95 percent of the pile is distributed all along this site,

Now you may conclude based on 5 piles that these remaining piles are safe we have adjusted the design but what surety you have over the distribution of soil within a 1000 meter length it may be very difficult decision So instead you go for the remainder of the pile with simplified method instead of going and putting a big weight and then measuring the displacement and strain you do a simplified method of pro rating the capacity based on certain small scale testing which is what we used in dynamic testing and which is very useful in many cases,

It proved to be So if you do a full-scale testing and on the same pile you do a dynamic testing compared capacity then you can actually get a very good feel how the dynamic testing is fairing with regards to the full-scale gravity testing and your design your theoretical design you have 3 numbers to compare and then you can come to a conclusion,

 And then the remainder of the piles you go and do a So you can see the correlation is very important from gravity testing to a dynamic testing to a engineering design then you go back and do the remainder of the pile you have only engineering design adjustment plus the dynamic testing ,

So this procedure is adopted in most of the large-scale projects but of course if you look at only some projects were only 5 piles 10 piles are there and subject and dimensions of the structure is so small like 50 meter by 50 meter the variability may not be that great so you can do only one pile test and you can leave it,

 And in the application of such simplified methods for pile monitoring for offshore structures is very much useful like what we have learned about your medical scheme to calculate the number of blows required to drive a pile to a particular depth of penetration using a particular hammer,

You can back calculate and it is called pile monitoring system that means you will use the information during driving and then calculate what resistance it would have been offered by the the soil during driving,

And then you just adjust it to long-term capacity using several parameters and then you can predict or at the end of driving you can say the pile would have achieved this much capacity,

Now what you did avoiding here you are not going to place a big weight and try to do a measurement of displacement which is quite cumbersome especially when the pilot very large and the load is huge ,

And that is why the pile monitoring system is one of the indirect means of getting pile capacity in offshore condition and that is what we are going to discuss at the last And in the recent times in the last 10 years,

Or so another method of permanent implant of device into the pile system which is adapted for concrete piles at least You know basically before you install the concrete pile you would a load cell at the bottom of the concrete pile itself,

And just cause the pile and afterwards you have a activation system a wire will come to the ground so you can activate the hydraulics and you just push the pile against the soil resistance And this can be done for ultimate test,

Or it can be so this O-cell test is also employed in some of the onshore projects bridge projects in US but very in this part of the world because it is quite expensive you need to embark a complete load cell inside the pile itself,

Permanently you cannot extract them afterwards so it is just left over there So this O-cell is basically Oster berg cell name after the person the professor who found this method for one of the bridge project in US,

It is in use for quite very useful and few projects we have used it for offshore or coastal so we will go through each one area by little bit detail So the purpose of pile load test is to find out the install pile capacity and verify and remove the uncertainty of associated with the assessment,

That we have gone through do during boring taking Sample and then to laboratory test and then properties and unknown properties are calibrated using past you know information So all those things will be removed once you have the actual capacity versus the displacement,

And to assess the load displacement basically there is no critical information that easy to relate the capacity versus displacement You might have already got the methodology to evaluate the bearing capacity,

 A multi layer site what you saw was basically a single soil layer giving a theoretical relationship between the capacity and the displacement whereas when we have a multi layer soil the behavior itself is going to be complex and the only way to get the load displacement relationship is to carry out complete load test,which will be a prototype in nature you are not doing a scale model like our laboratory,

So the primary purpose is to link and assess the load displacement characteristics of a particular pile at a site So the test can be of in fact 3 categories basically the one that normally carry out is the static load test the load is static in nature and that the dynamic load test which is what we were talking about,

The quicker and the cheaper methods Then we have the bidirectional method using O cell you can actually do this way or the other way In the static load test we have got variety of load application methods,

One is the constant rate of penetration imagine if you have the pile already installed and try to do the loading the displacement is not under control so that means if you go by this method whatever displacement comes you will actually note down whereas if you actually control the displacement by changing the load according to the displacement characteristics,

The rate of petition can be controlled So but the first one is quite obviously very difficult to do because you have to continuously having a monetary system of displacement and adjust the loading according to the rate of penetration,

Not many of the contractors have this facility because you need a feedback loop so that when the displacement increases you have to decrease the loading and it is only feasible by hydraulic means where as normally most of the most load test,

You see in the field they all just put big weights so removal of weight is going to be very difficult So most of the time we do maintained the load test you put one weight weight for several hours according to the procedure and monitor the displacement,

If the displacement become constants that mean for that particular load soil has achieved its maximum possible displacement Then go to the next load displacement and apply the loading wait for several hours and vice versa you remove the loading and look at any elastic rebound happening or is a plastic failure,

So basically this maintained load test is commonly used in most of the projects very rarely we go for this particular method Dynamic load testing we have very similar idea like you know the pile hammer when you take a hammer and drop onto the pile and you see the stress waves travel through the pile and get reflected,

If the absorption is not enough and you measure the statistics of the transmitted stress waves and reflected stress waves and depending on the reflection and the transmission you back calculate using the same principle,

What we were looking at the the dynamic equation and calculate that what would have been the resistance offered by the soil because this much waves has reflected back from the soil itself So that is indirect means but before going and doing the actual testing at the site you may have to actually do a calibration in a known material which is easy to do,

After that you can compare with the known material versus actual pile at the site this is you got 2 types of tests one is the high strain dynamic testing the other one is the low strain dynamic testing just the weight of the hammer and the low strain dynamic testing is normally preferred because for concrete piles,

If you do a high impact the pile itself will actually fail Pile monitoring I think we will talk about it little later it is a simple idea of using the driving information or driving records number of blow counts and you know the duration between the blow,

Sometimes you will have major stresses at the pile tip at the top and calculate back the resistance which is also is dynamic because you are using the pile the hammer impact loading Bidirectional method is quite useful only for the O cell testing which is you can do testing in both directions, because the load cell itself is planted into the the pile foundation,

So you can do vertical load test you can do compression tension I think obviously some of the piles in coastal areas for example berthing structures you will have compression loading and tension loading depending on the magnitude of horizontal load,

So the pile needs to be tested for compression and tension as we calculate the capacity you know pile capacity we calculate using skin friction pleasant bearing that is for compression For tension you will have only skin friction depending on whether the pile is plugged or unplugged,

You will see the internal and external So in this case the tension testing is required for only few number of files for example even if you design a structure the whole structure does not have any tension loading that you do not need to do this type of testing,

But most of the berthing structures will have tension because the gravity loading is very less and it is predominantly going to resist the horizontal loads like ship berthing structures so you will see a huge amount of tension coming at you have to make sure that the pile has sufficient penetration to take the tension loading,

It is not the whole structure will pulled off In many cases what we normally do is if you are unable to penetrate that much longer than you actually do a anchoring of the pile into the ground means you will do a smaller hole we will talk about one of the days,

I think later in one of the sessions about encourage files only for tension loading which is very essential for such type of design Then we have also lateral test static and cyclic and you can see here static test is going to give you certain capacity which will degrade when you apply the same loading,

Several times because the top layer of the soil as we have learned from our P-Y curve near the seabed you can see the soil gets disturbed quite a bit because of the repeated nature of loading and degrade the displacement or increase the displacement degrade the capacity,

So we need to see after how many cycles the capacity gets that means you would see that displacement would be more Then we have loading limit whether to load to the ultimate failure stage that means the pile will go into permanent deformation and the soil or you want to do a routine test by which you will not destroy the pile,

You will only do a extend of maximum working load the structure may get and stop it so that the same pile can be used for permanent construction as part of the structure so either way we can decide Only problem is there is an uncertainty in the second one you know you do not know what behavior,

It will go through after it achieves that so-called working load limit because it can fail straight away plastic deformation can happen or it can have a redundancy after that which will not be revealed when you do the working load test,

Whereas when you do this you will be able to find out at what load the pile is failing then you know what is the factor of sifting because the factor of safety is defined as the ultimate load by working load or ultimate capacity by working load,

So you will only be able to ascertain the factor of safety if you are able to find the ultimate load of what you will not be ascertain that factor of safety because in the working load test you only have that level it may actually fail after just going slightly higher than the working load which will not give you the comfort-ability of the factor of safety,

So that is why the working load test is normally not preferred but then cost versus your factor of safety and design requirements You have to decide how many number of piles you want to do ultimate load test and how many you will do a working load test,

But of course if the test result so large scatter then you will increase the number of piles that you do testing If you do a 5 piles and all 5 of them are shows very reasonable matching of results and you may have actually conclude that no further testing is required but each one of them shows different results and different variations in displacement characteristics you may actually decide to do,

Furthermore addition to the pile testing which again is is actually an procedure is decided by the the site representatives I think we have discussed the performance is design validation I think the primary purpose is design validation whatever corruption you have made during your bore holes and to the design stage,

You would like to validate that those assumptions are nullified so that your process of construction can go Quality control for sure in concrete pile is one of the biggest worry in fact steel pile you do not have such issues but the quality control of concrete pile construction,

Because everything goes underwater you have to displace I think we have discussed about the construction of concrete pile you have to displace the slurry which was poured inside by means of good quality concrete but the quality could not be ascertained because nobody can go inside So when you do this kind of low strain dynamic testing you could also assess the concrete the honey combing structure,

If the concrete is not done properly you will see that the reflected waves will differ from the solid concrete that if you have you can actually have uh testing of pile itself whether the pile is sound enough to reflect and transmit the waves or if the pile has got low honey combing inside also can reveal Similarly for steel piles if the file has been broken during driving and if you do this testing and it will reveal that if the stress waves are not coming you could easily find out where is the fault,

So that is the idea behind this the low strain dynamic testing So basically quality control of the construction itself can be verified by means of carrying out cross correlation test Sometimes you do a design development you know you basically you have a large number of some projects of thousands of piles like if you go to some of the large-scale industrial projects,

You may have several hundred piles So you do a representative pile testing and use that information to further develop and then come up with a design procedure In many cases if you if you look at some of the large-scale projects they actually develop new design procedures specific to the site using the design data collected from the pile load test plus the portable information,

And they come up with their own design strategy and the you know you do not need to follow the standard procedure given in either any of the codes or regulations because it is proved by testing at the site so that will be done sometimes And in many cases always you will use it for further refinement of academic interest,

I think these these are secondary but of course insufficient site investigation normally you do not do a construction without the site investigation but then all depends on you know the the owners intention sometimes some government organisations may not be able to do a site investigation,

Before the hour of contract to the contractor because of the nature of limitations they have They may not be able to allocate funds separately for site investigation and separate for construction it is part of the construction itself So what happens is when a contractor comes to the site they have no clue what is the site so they will be doing the site investigation so that is the time when the design becomes difficult the design has to be evolving based on the available information,

But not actual site information Many cases that happens so you do that at that time when the project starts you have assumed certain parameters during design and then you proceed with the construction but then do the testing 1st Once you do the testing your assumed information verified and several other limitations on you know basically cost is one of the primary parameters,

Nobody wants to do testing if they can live an engineered design I think everyone will be happy but that will not be the Now guidance from Handbook of pile load testing this is just give you an idea of how to decide how many piles is good for a particular site,

You know just of course this is only a guidance it will need to be decided by the site engineer and the and the owner of course for sure depending on how much of time and money is located for that purpose,

But typically you can see the complex or very much unknown ground conditions you know it is isolated place no one has constructed in the vicinity so then probably you can go for a large number of So you see here they recommended is 1 preliminary pile test per 250 piles so that means preliminary means this pile will not be allowed to be used in the permanent construction,

So you do a separate file at an isolated location within the periphery of the the boundary where the structure is going to be built It will not be within inside because what you do not want you do not want to fail the soil between close vicinity of a working pile,

For example you have a pile here and just half a meter away or 1 meter away you want to construct a pile and fill it which is not very good because you cannot install another pile in the because the soil already have mobilized its full strength and failed,

So normally you will go little bit away but not very far you cannot do the testing several kilometres away it does not represents the actual site conditions So within the parameters probably representative location you will do a 1 preliminary test for 250 piles,

So you can see here it is only a guess there is no rule book or it is not representing some kind of you know relationship it is only a guess that it may actually give you some information plus 1 working pile test for every hundred piles,

That means among the remainder of the piles every hundred piles you select one and then do a where the the ground conditions are very much unknown probably not very clear No previous pile test data is available in the site new piling technique is used in case in that area every time,

They were using a concrete pile but suddenly you are going to use a test you are going to use a steel pile then it is an unknown experience very limited information available in such cases you do this Where as if it is the other cases you know your risk is reduced with reasonable information then you can increase or decrease the number of piles per testing,

So you see here 1 preliminary test for 500 piles which and then for very low or in fact you got plenty of data then you can also use 1 in 500 1 in 100 or 1 in 200 In fact codes are not suggesting any of these numbers because they leave it to the,

You know the owners or consultants who are representing the design validation So normally we design something very similar like this 1 in 250 but not very projects will have 250 piles you know maybe 10 20 50 so if you do one pile that itself is good enough,

So this is only a guidance which if you are representing your company for pile testing or if you are writing a specifications for pile testing you can put that kind of number Rabbit load test versus dynamic load test you know the kind of capacity that you expect you know 30 mega Newton is $ 3000 tonnes and what kind of hammer,

You will be using just information that you can use it that much is practically possible to do the testing So if you remember we were talking about pile capacity in offshore pile system I think we were talking about 20 to 30 mega Newton for each pile which is something like this,

So it is not that we cannot do it can be done but at a very expensive system design because water depth is more and you want to design a reaction pile for such type of testing will become costlier than your jacket so that is why we avoid,

I think we just discussed about static maintained load of test versus static penetration test or the so-called constant penetration test you can read some of the information about the past history of what was done the maximum load of what was achieved in the previous several years it can be done to that much of load 3000 times,

So you will see if you go around some of the the pile way construction I think MRT construction is going on I think 6 months back so many places they were doing pile testing for the pillars the big pillars you will see that a use platform is built and concrete blocks are stacked upon each was about 600 tonnes,

So you can see that the bulkiness of that platform to load this 600 tonnes because you calculate a 600 tonnes by either by sandbags or by concrete blocks you will get 3 to 4 layers of concrete blocks will come So safe working load ultimate load and design verification load sometimes differ from we discussed about safe working load is a working load of the pile as per the design requirement Ultimate load includes the factor of safety that means either 2 or 2 and half or whatever the design factor of safety,

As per the design code If it is a IS code you normally use 2 or 2 and a half whereas API code we use 1.51 through and so this is the test load that you will apply if you do ultimate load test Sometimes design verification load is in between these 2 we go 50 percent overload instead of failing the pile,

We do a pile load test taking between the working load and the ultimate load sometimes 25 percent higher than the working load Still the pile can be reused because you are not failing it but it is slightly overloaded just to see that how the behavior goes,

Because if the pile fails immediately after reaching the working load after say 5 percent the the factor of safety is not there anymore So design verification load it can be any one of them or it can be in between also A typical onshore pile load test we will just read the methodology how it is carried out,

So you can here this is a good ground condition means the ground at the surface is reasonably good So we have a gravity based support system something like this you construct pillars sometimes we actually use concrete blocks,

You know simply put on 4 Corners make a steel beam something like this and just you have your pile previously installed which is going to be tested and then with a prepared pile head it could be a concrete piece or steel piece placed on top and then you start stacking up your weight because while you are stacking up because people have to go up and load,

It or you your Crane has to bring material and then just keep stacking up And then you will place a hydraulic jack or Jacks 1 or 4 of them normally 4 of them is used and just jack it up So what happens is previously when it was loading is done at that time no load is going to the pile and safe because for a longer duration,

You do not want to keep this condition because it will topple or slides down to sideways you will be putting big danger on the pile itself as well as the system So normally you have this is called Cantalage weight distribution system this is feasible only when the ground conditions are good number 1 and also the the distance from the pile should be sufficient enough that the load does not actually alter the soil conditions in the vicinity of the pile,

Imagine if you do this and if the soil gets actually squeezed and get compressed the pile capacity that you are actually going to measure is not going to be represented in the actual site condition because already the soil has been compressed and consolidated,

So that is why you have to keep this support system quite away from the pile itself so you have to keep it 3 diameter to 4 diameter away so this cantalage becomes actually very large depth girders normally you will see 2 meter-3 meter girders spanning between the supports something like this you have to keep 10 meters away if it is a 2 meter-3 meter pile,

So they will be away so that that influence of the reaction is not coming back to the soil So this is a typical onshore pile load test that using you know spread footing type reaction system so that is the idea put behind So this test can be repeated if it is a working load test you just load-unload load-unload,

But load will not be applied in one single stage normally because then you you will only get one load one displacement relationship So you actually divide the total load into say several steps if it is a 300 times divided into say 5 or 6 steps and put 300 into say 6 steps means 50 tonnes and just look at the displacement then go to hundred tonnes wait for some time and till the displacement becomes constant,

Then you take the displacement reading go and put the further loading so it is just done in steps And then similarly you can do a unloading so from 300 you come to 250 and 200 and so on so you can see whether the loading path and unloading path is same or different,

If there is a plastic deformation then you will see that there is a different load path from loading to unloading so that also can be verified If it is a soil condition that the top surface soil is not good or it is going to distribute the load very close to the the pile that is being tested then you may actually look at installing additional piles and this is the case most of the cases it happens like this So install additional number of piles in and around the test pile,

Normally 4 number of piles are installed and you prepare a cantalage which is nothing but a just a grid of beams which will support these weights to re stacking during unloading process and then when you want to do the testing you simply use the hydraulic jacks to activate,

And then lift it up So you can see the difference between soft bound you know soil condition at the surface to good soil condition the expense increases several folds You can see here here just only a simple pedestal support quick to make easy to remove where as when you go to this one you can see here for one pile load test,

You are installing 4 number of piles so you can see the the multiplication of the time and the cost and the removal you have to remove these piles you cannot leave them there itself unless it is isolated place,

So basically the procedure is same only the difference is depending on pile condition you will do the support reaction and cantalage according to the requirement And if you are going to do the same testing in coastal waters 5 meter 10 meter 15 meter 100 meter water depth can we do this,

So that is where we bifurcated into a different idea if it is a 20 meter water depth yeh probably you can design a pile which will be directed around the other load testing pile and make a platform something like this and then construct this frame load and unload can be done up to say 10 meter 15 meter 20 meter,

But when you go beyond 25 meters will easily see that the diameter of the pile tested and diameter of the support frame the diameter 0 becomes too large If you actually have to do a pile test in say jacket location 100 meter water depth because jacket is still not there because jacket will come only after you complete all your design and everything,

You cannot do testing of a pile through a leg for sure it is impossible So when you want to do this 100 meter water depth imaging you may have to actually specially fabricate a jacket vertical in nature is not it something like this and keep the frame there and put the pile inside and do the testing,

That means, it becomes another project so that is why this pile testing is completely not feasible so maximum pile testing I think for coastal areas people have done up to 20-25 meters maximum beyond which you will see that the design of the system itself becomes a problem,

Specially when you are doing so much loading coastal areas 300 400 500 tonnes But for jacket type of structure if you want to mobilize weight of 3000 tonnes which is becoming a bigger problem so how to avoid even in coastal areas even in land based structures can we do testing without this weight,

This is one of the very good idea so that you can avoid for example if I go and connect this beam with this pipe so what will happen I do not want to put the weights here so instead of using this weight as a reaction what we want to do is we have simply weld this this beam with this pile So what happens,

When you are actually putting up the hydraulic jack the reaction will come from soil itself so that is basically the idea in the recent times no one wants to do a this this is called Dead weight method of testing,

And you can just look and eliminate the so much of weight bringing the weight stacking upon and removal can be removed provided these piles which were installed as a reaction pile or a support pile has sufficient pullout capacity otherwise that pile will come,

You do not know whether you are measuring the this displacement of this pile or whether you are measuring the pullout of the other pile which will become a very complicated situation,

Pile Load test

PILE LOAD TEST PART -2

Let us continue with the pile testing so by this I think you could understand the 3 concepts concept 1 foundation by means of simple spread footing for the cantalage itself And basically pile foundation where the ground condition does not permit Load distribution around the test pile the primary concern is we should not put undue load to the pile soil interface which is being tested,

So that is why we have to space it larger enough so that the pressure from the thus upload pile cantalage support pile does not affect or influence the result of the test pile itself that is one concern The 2nd concern you know when you are doing measurement of a displacement of the pile being tested you need to have a firm ground or a darter line by which you will be able to measure the the settlement,

For example in this case the ground condition is good and also you have accessible ground so you just put the darter line which is not going to change over period of time during the testing So if there is a easy way of putting a dial gauge with respect to the ground and then measure the movement of the pile,

Now if you go to the offshore condition what happens if you have no firm condition or firm ground you have to use only the the pile which is supporting the cantalage but at the time of testing it is not loaded anymore,

So you can use that as a reference and use a beam or some welded connection so that you can use the dial gauge So what we need is the the firm place it is not moving during the testing so that is one of the 2nd concern And then when you are doing the testing,

In any case it is not influencing the soil-pile interface or the capacity of the test pile which is being done the now-that is one of the idea so you need to keep it faraway 3 to 4 diameters so your cantalage anyway will require a larger space to stack up the waste and things like this Very rarely in coastal areas we do this because,

It is very expensive one of the tests could take months to set up and do it and bring back A typical cantalage test which is just on land so you can see here even in this particular case it was done in one location in Kakinada where last year before you can see piles were driven so this ground condition was so bad that even you cannot spread the load which coming from so much of sandbags,

So we need to have piles going down to a firm ground because the total top 15 meter of soil is play soft clay and if you try to put some spread footing it will definitely think under this kind of support reaction load during stacking and then you cannot retrieve and every time when you just load and unload the foundation becomes no use,

So that is the picture that you are seeing the pile is being tested which is at the middle and basically the pile will be provided with a pile cap steel plate and these are the jacks which are just placed between the cantalage and pile head just to stack of you know And the dial gauge can see here is placed at this place and this is the reference to the pile head itself,

And this is the bottom line which is not moving So when the pile is moving up the dial gauge will show the displacement every time when your how much pressure you are applying The alternate ways also because instead of instead of going for cantalage with self weight or dead weight,

We can actually use this method by using the pile itself as a reaction frame So you do need to stack up weights only thing is the load is produced onto the test pile by means of the compression load because you are just holding this cantalage frame on the sides using the pile so this is being a welded connection,

So always this anchor pile will be under tension so you need to have sufficient capacity of the anchor pile so that so that means if you are testing a 3000 tonnes here each one of them will have to be divided by 4 and recently have designed with the adequate penetration because it is only tension At least this pile have the N bearing whereas the anchor pile will not have N bearing so you need to have sufficient penetration sometime it may become very large,

And basically bigger bigger than the test pile because you need bigger capacity in tension than the test pile is being a compression capacity so you have to be little bit So that is where this method becomes little bit difficult because it might become very expensive,

When you compare with this maybe better because you do not need to mobilize so much of material movement every time because it is not one-time you will see that later on the sandbags have gone back and forth several times because you have to do loading sequence and unloading sequence and you have to repeat the test at least 2 times,

And that is where you find this is a time-consuming process and also very expensive Anchor pile seems to be very good but then caution needs to be taken in terms of design make sure that when the pile is being tested this is the anchor that you have designed it is not going too much,

Otherwise you will be measuring actually relative movement of the pile anchor pile and the pile being tested Typical reaction pile setup so you can see here this is the pile being tested pile requires to be tested otherwise you have the jack being placed at the and these are the pile heads the left side and right side you see the pile heads which the piles are being driven with the pile head,

And when you just push this hydraulic jack upwards the reaction being applied to the test pile and these the reaction piles on the left side and right side should have sufficient capacity and basically that should be designed And just a closer view of how the hydraulic jack is placed in the girder,

So that it reacts against the test pile as well as the reaction pile Another load test using concrete blocks instead of sandbags many times people use this because it is easy to handle and can be used in multiple places only require storage,

But in any case in construction sites you will find many of these concrete blocks uhh spare capacities available there but many times people use these sandbags because easy to dispose because they can be used for construction work no extra storage space is required and each one of them will be weight before placing it on the top so that you know the weight what it is only the stability of them,

Sometimes bit of a worry because even a small eccentricity caused by either placement or by you know stability the whole thing can be turned In many places if you notice pile load test failed because of the cantalage tilted or cantalage failed which will cause quite a bit of problem,

Whereas using concrete blocks is quite useful because it is very stable sometimes these concrete blocks will come with a sheer case so you can have an opening at the bottom and you can when you place it it will not go anywhere and horizontal stability is well-established,

We can have precast blocks specially for testing not just for any other purpose So the ultimate load test is basically done to the load which is taken to the maximum failure capacity of the pile which will be 2 times or 3 times depending on what the factor of safety used in the particular project of particular core of design,

It is most of the time for IS codes we design for factor of safety for 3 which is for concrete piles which actually says 2 to 3 but then mostly we use factor of safety of 3 that means you find out what is the load that is designed for for working conditions take it to factor of safety of 3 and then find out So typically,

If you look at 300 tonnes is a working load most of the 1 meter-1 and half meter diameter piles then you multiply by 3 you will take to nearly thousand tonnes so imagine thousand tonnes what could be the requirement for dead weights Working load test is typically one and a half times safe working load so we want to go for slight overloading,

But not to the ultimate stage As long as you want to see passing of the working load and also have little bit of budget get depends on how much design margin is available at sometimes be reduced to 25 percent we normally call it overload test Even mechanical devices nowadays everyone of them the working load test is not acceptable,

You have to go for slightly overload because if the load exceeds the working load even by slight amount it should not fail so that is why overload test is about 25 to 50 percent So the 2 methods of testing that we were discussing the other day is constant rate of penetration or maintained load constant rate of penetration is just you can see here 0.75 mm per minute,

So it is a quite slow process and that eventually required by the British code 800 is for design of foundations And maintained load test typically used in most part of this construction site in India is very easy to carry out you do need a sophisticated loop back system simply put the weight and get the whereas the constant rate of penetration,

You need a good amount of instrumentation to read the the penetration backward and adjust the pressure accordingly and it can only be done by hydraulic system not by dead weight and cantalage method it is just not feasible,

Whereas the maintained load test even in a very simple method which you need a dead weight and a jack And the load shall be maintained constant until settlement rate is decreased to 0.25 mm per hour so what we normally do is use you set up your cantalage put the weights safer example 900 tonnes divided into say 5 steps or 6 steps,

So the step 1 of the load and this activates hydraulic jack to transfer the load to the test pile relieving the Anchorage piles or support system and then monitor the displacement Initially displacement of the pile may be larger slowly  reducing indicating that the soil has achieved its failure state at that load and then it will go constant or may slightly increase in a very low implement,

So once you see that it becomes flat the displacement graph is flat that means you are not expecting any more images settlements you may actually expect long-term settlement which may be several years which is we are not interested in that So basically then how do you decide when to stop the or when to restart,

The unloading process because every time you are going to unload it bring to 0 then stack up to the next increment So 1st time say you arriving 200 tonnes and bring to 0 that means you have to take out the load and load it again to 400 tonnes so that process when you want to start as soon as you see the displacement relationship is going flat,

That will be better but if the rate is still within this then you can go that means when the displacement is happening you cannot do unloading process So maintained load test is quite simple we will see the procedure later on something like this so you see here you put the 200 tonnes and then that the displacement is increasing,

So what you will see is when you are doing unloading process if there is elastic part it will come back There is permanent deformation of the soil that will not come back that will be residual so it will keep on stacking up so that is what we are interested in Similarly we go to the 2nd 2nd step so when the 200 ton weight is placed on the cantalage,

When you relieved the hydraulic jack the load will go back to the support stock then put another 200-300 tonnes on top of it It will become 400 ton take the hydraulic jack and load it on to the pile and just repeat the procedure until you reach the total test load it could be ultimate test load or it could be working test load,

And every time you do this you will see a loading-unloading curve you can see so basically you will be taking this as a displacement 9 mm 8.5 mm for 200 tonnes so you can go and plot here load displacement in a different relationship,

And typically we will take several hours because get this flat curve sometimes you may have to wait longer time depending on type of soil if it is a sandy material you will get the displacement quickly after that it will just become flat If it is a clay it might take little bit longer time but then instead of setting this criteria IS codes actually gives the time to wait for one hour depending depending on  type of soil,

You may only vary little bit So if you look at the procedure given in IS codes it will give you the timing every time step how much time you need to wait and then start the process of loading-unloading In fact this this particular procedure is taken from pile testing manual which I was talking about day 1,

So the design specifications load all it is basically the test load if it is ultimate test design verification load will be your total load multiplied by the fact of safety 25 percent 50 percent 75 percent so this procedure is just segmented into 4 subdivisions 30 minutes so once you load 25 percent load wait for 30 minutes and 100 percent load wait for little longer time,

And then during the unloading process only because relieving of elastic compression will take just like this it is not going to take time so unloading time they are just allowing you to only little time 10 minutes And then again we start the process  100 percent and you are going to do a overloading test,

There you are going to wait for little longer time beyond the design verification load if it is a working load test and then repeat the procedure So basically this is just typical time versus increment of load,

I have just taken from the you know the manual of pile load testing from the Association of civil engineering contractors every everywhere they used this but if you look at the IS codes they may actually gives slightly different numbers and different timings,

You know so depending on which jurisdiction you want to use So if you look at this graph load displacement curve for ultimate load test up to failure So you can see depending on type of foundation material you will see 3 types of so if you look at the blue one N bearing and V crock basically it increases and then suddenly fails,

So you will see a certain capacity reaching the rock is trying to fail so almost like elastic and perfectly plastic so something similar like this And if you look at the black one friction pile in soft clay or sand you will see that highly nonlinear it keeps increasing and then the failure rate will be slow down achieving certain capacity,

Or else if you have a fiction pile in stiff clay also will be very similar but then there will be a downgrade effect because the stiff clay broke down when it is achieving the so typically you will see something similar when you plot the when you extract the displacement from  such plots,

Nowadays you can automate these kinds of things so automatically we will get a time bound graph then you can later take the displacement come up with the displacement versus the applied load graph is something like this and basically you need to decide,

Now what capacity is to be taken as ultimate or working load So depending on what the allowable all ultimate reflection that you want to permit remember when we were doing the TZ curve for clay and sand we were talking about 0.1 inch for sand and then 1 percent for clay something like this,

So that corresponds to the ultimate failure whether you want to consider here for steel piles has to be decided by what is your ultimate failure to state you want to define So once you define that limiting load or limiting displacement then you can go onto the graph you can take this is my ultimate failure load of the pile beyond which we will not be able to take it Saturday is the idea behind construction of this diagram is just to make sure that your TZ graph you have made is going to be reflected here,

And if you get a representative from here and that will be realistic because this is based on test where as the other one is based on historical data and empirical methods So you see here in this particular one the ultimate capacity at 25 mm settlement is taken as 425 tonnes,

So though it is highly nonlinear some amount of plastic deformation have happened compared to when you go to the blue if you look at it this is completely elastic and after that only becomes the plateau so you can see the difference So that is the way we want to determine,

When you do a testing I want to determine what is the ultimate capacity The thing is you have to sum up what is the displacement at which you would like to take for example when you are designing a structure you will always have a limiting deflection in both horizontal and vertical working load conditions,

So then if you are allowable capacity you want to find from this then suppose your fix rate 10mm is the allowable displacement during service life of the structure then 10 you just go to 10mm the pile has achieved a 350 tonnes,

Pile Load test

Now if you take the ultimate capacity apply a factor of safety of 3 or 2 you will only get something like 120 tons so that is what will be revealed here If you do not know about this graph is going what you are trying to do is if you take 420 tons join from here straight away to 0 make a straight line that is what you are doing by means of factor of safety 420 divided by factor of safety of 3 on load,

Whereas if you have this this graph you know very well that you can allow maximum of 10 mm during its service life with the factor or on factor load then you can decide how much margin you have almost large margin is available,

When you take 10 mm and restrict to 10 MM is the displacement 420 decided by factor of safety of 3 you will get around 130 tons that is what you are going to permit But actually the pile has got deserved capacity up to 350 at the same 10 MM displacement,

So that will be the difference when you have nonlinear load deflection curve especially after testing So this will give you a picture how much extra margin you have because of the soil behavior and if you take this one you will not get anything better is not it Because you are grabbing almost linear relationship,

If you take that will be the capacity of say 550 tonnes divided by straight away factor of safety of 3 you will get somewhere around 180 tonnes Whether it is 10 MM or 5 MM you are going to just linearly prorate so does not matter So that is the idea of constructing or establishing load displacement characteristics up to failure,

If we have only established up to for example some lower displacement because you are not going to do a failure test you are going to do a working load test just up to the linear portion then you may not actually reveal how the behavior after this this is why at least one or 2 piles at the site you have to do up to failure to see how much margin,

You have It can behave this way which we do not know unless you do the testing Then we also move onto horizontal load test basically similarly you can do horizontal load test One of the biggest problems is doing reaction she just now we have learned about vertical load test with support arrangement,

Somehow we can make it because it is similar piles can be driven but when you do horizontal load test you need to have some ground or firm support condition just to measure the horizontal displacement of the pile and also to transfer the reaction from the jacks which is going to be a big challenge So doing it onshore itself is a challenge,

Then when you are doing it in coastal or offshore conditions it is even a challenge because you have to design a system stronger than the test pile itself and install it And also you can carry out cycling load test in cases of coastal structures where cyclic behavior is required for degradation effects So typically you see here some working platform is required,

And I would have just straightaway gone to the coastal areas where some of the berthing structures we still do this lateral load test to establish the capacity in horizontal direction but most of the structure on land normally we do not do you know horizontal load test not really required,

Because predominantly it is not so much problem so far for buildings and bridges predominantly gravity load So you see here we have a test pile which is in yellow colour and we have a reaction pile and just the jack,

Now you see here the jack is placed in between attached to both the pile heads and the jack is trying to expand by giving horizontal load through the test pile the reaction is transferred to the reaction pile Noise they reaction pile stable the reaction pile displacement is smaller or ignoble then what you are measuring is the pile head displacement otherwise he will be measuring the relative displacement,

Because this pile is also moving the other pile also moving and how much we have to find out So you need a chili credit system to find out what will be the displacement which will be quite tough,

Because you can theoretically calculate but then it may not be correct A reference will be used another few numbers of piles is required or system is required to support all this as well as access to these places,

So you will see that horizontal load test becomes reasonably expensive because you have reaction frame and you also have a reference frame the reference frame the green colour what you see is a reference frame against which you will do the measurement of displacements,

And they are need to be placed sufficiently you know wider spacing otherwise what happens when you are doing when you are doing reaction here when the pile is trying to bend it puts undue pressure on the soil and that soil gets affected by this particular location and behavior of the lateral capacity is going to be affected to some extent and that is why you have to have minimum of 3 diameter or 4 diameter or 5 diameter,

Once it become wider spacing mounting of the jack becomes a problem you need to design a frame and that is going to put you onto support system together it has to be mounted onto the 2 piles which needs to be free to move so that is one of the challenge A typical cyclic load test results or plot how you carry out loading and unloading process basically horizontal load versus lateral load displacement,

You take it one cycle at particular load level bring it to 0 repeat it few times just to get the repeatability and again increase the higher load repeat it again load and unload since there is no dead weights are involved it is only hydraulic jack doing such load test is very easy then you repeat it again and again for various loads and stop,

When you actually reach the expected displacement for example ultimate load test you are trying to do for 100 mm maximum If you are doing a ultimate horizontal failure load test then you can go up to failure of the pile and stop otherwise you have a predetermined load by which it will not be a larger capacity,

Most of the pile if you look at 50 tonnes or maybe maximum 70-80 tons unlike the vertical capacity where you have thousands of tons or sometimes very large number Here it all be you know restricted by the pile horizontal shear because if the soil does not fail what will happen the pile will fail,

So if you look at the Shell capacity of the pile that will give you the maximum magnitude by which you can test in fact will apply factor of safety on it What you do not want you do not want the system to fail before the soil fails system means the pile itself or the anchor pile itself,

So you will find out what is the bending capacity of the pile or structural capacity and shear capacity Make sure that you have got sufficient factor of safety available on the structural system prior to go to ultimate load test,

Because you do not want the system to fail when there will be a catastrophe And in some cases in the coastal structures like berthing structures we may require pullout test because some of the piles are actually going to have tension capacity requirement especially when you build a berthing structure the front pile will be in tension the back pile will be in compression,

When you are having shift or berthing against the berthing structure So such you may require a pullout test instead of a compression test it is exactly opposite of it only the cantalage placement and the hydraulic jack placement is in the reverse condition,

If we just go back to our the this test somewhere here I think something like this so this this one is anchor pile method you are doing a compression test just reverse the process and placement of the hydraulic jack you will get the So basically the cantalage arrangement is attached to the reaction pile,

And there will be stress blocks and you have hydraulic jacks and then you attach your brackets welded to the test pile itself So what you are trying to do is you are compressing the reaction pile and pulling up the test pile so basically you are just reversing the reaction just to get what tension capacity is available Many times you will require this for coastal structures but magnitude will be not very big,

Few hundred tons So what are the things that we need to note down when you are doing a compression load test the support frame needs to be designed appropriately because you you have such a large weight to be placed Support piles needs to be placed away by 3 diameter that makes the so if you have 2 meter diameter pile you need to go for either side 3 meters 3 times 2 meters 6 meters so the frame becomes 12 by 12 or 15 by 15 Structural capacities of test pile,

As well as the support piles leads to be made sure that it has good adequate capacity Special care must be given to the test pile because it is a cantilever whereas actually the same pile when it is working in the actual structural system it may not be a cantilever it may be combined pile heads with the other structures,

Whereas when you are doing testing it is a pure cantilever you must remember what is the difference between pile in a temporary condition which is a cantilever to a supported pile in the permanent condition because of high level buckling The load capacity will come down drastically,

So you cannot think about always you have pile 1 meter diameter in a permanent system which is connected to a bigger structure which may not behave as a pure cantilever so the effective length and the conditions are different you are 1 meter diameter pile may work there whereas the same 1 meter diameter pile,

When you bring to the test category it becomes a pure cantilever number 1 high-level buckling load will be definitely half or less than the actual buckling capacity When you are doing the same ultimate load test here you do not want the pile to fail So what we really need to do is keep the diameter same because you need you do not want to change the pile-soil interface is not it Because we want to test the 1 meter diameter,

But what you can do is you can increase the wall thickness to increase the bending stiffness buckling capacity shear capacity in such a way that structure does not fail but the soil pile interface is being tested,

You understand the idea know so you need to make sure this otherwise if you bring the same pile and testing before the soil fails the pile collapses and then it puts the whole system into problem that is what you have to make sure So what IS codes are suggesting instead of what we saw was 25, 50, 75 they have divided into 5 sub-segments of loading 20, 40,60.80 to 100 so it is just a little difference,

And basically loading-unloading cycles almost similar I am not very sure whether I have copied the time cycle You can look at the code the time is also given 30 minutes up to 6 hours so you can refer to the code but what the criteria,

I wanted to look at it is basically when do we decide it has achieved its ultimate capacity and it is applicable only for concrete piles you cannot apply this one to steel tubular piles uhh it is not under that particular code So if you look at this graph,

I have just plotted one of the recent last year test two thirds of final load at which the total displacement attains value of 12 MM So you just look at the graph and just go around apply the criterion number 1 the safe load on a single pile for initial test should be least of the following,

So the criteria is given Do the testing comeback here plot the graph and look at these criteria whichever is lower that is your safe working load so that is the criteria that you are going to apply And of course this is written on the basis of onshore structures you know 2911 is a code for both the concrete piles for onshore applications not even for coastal applications that is why you cannot blindly apply this principle to a coastal structure on or offshore structure where displacement get area are different from dawn show structures,

You will see that they are very strict in terms of displacement because these are applicable to buildings and bridges or to some extent industrial structures on land where they are controlled by deflection Whereas if you go to coastal structures and offshore structures the displacement are definitely going to be larger,

You cannot even think of the criteria here because here they are talking about 25 MM When you think about coastal or offshore structure you are going to have several hundred millimetres of displacement because of the the magnitude of horizontal load you have to be a bit cautious and apply the principle differently 50 percent of final load at which the total displacement equal to 10 percent of the pile diameter,

So these are the 2 criteria so if you see there the criteria 1 and criteria 2 you can find out whichever is giving you the capacity I think even the lateral load also similar crater is given 50 percent of the final load at which the total displacement increases to 12 MM final load at which the total displacement corresponds to 5 MM and then any load corresponds to any specified displacement this is some at least some option is given for horizontal load,

So according to your project specific requirement so you specify I can go out to 50mm then I can look at so that if that is the thing that we need to have a decision-making process just doing load test alone will not be good enough you do not know what to do with that what you need is the demarcation what will be the acceptable displacement for that particular type of structure and applicable code in force,

What the API says we do not have a procedure to restrict the displacement unfortunately there is no requirement because we do not need because offshore structures are subjected to so much higher loading that if you restrict 25 mm displacement for example your structure will be so much bigger and may not be practical,

So that is why the the adapted method by API is to design by the factor of safety which gives you an adequate safety against pile failure or premature failure and at the same time you have a ductile material which is steel,

And you are not worried about failure by other means of fracture because the worry in concrete structure is larger displacement either in vertical direction or in horizontal direction can cause superstructure failure by fracture because the concrete cannot fail by the tail,

So that is one of the reasons why most of these concrete cores they restrict the displacement to smaller where as the offshore structures we never build using it except the concrete gravity platforms all the fixture types of structures are built by steel material has higher tensile capacity and also have a ductile characteristics In that reason we go by the method of engineering-based design based on soil properties with adequate factor of safety and we leave that we do not want to apply the restricting displacement,

The reason why we developed TZ all that is to make sure that pile is actually subjected to the actual load load displacement behavior and the bending stresses are calculated So if we have a larger displacement what happens is the pile is subjected to larger bending and larger bending means the requirement of section and the diameter and the thicknesses are going to increase,

So you design for it rather than trying to limit the displacement of the pile to lower value and increase the larger diameter so that is exactly the the design method adapted by API so so far I do not think any problem with that idea One of the issues with concrete pile supporting concrete structure is the architecture and finishers,

And serviceability requirement that is why it restricts the displacement to a very small value in fact the reason why we restrict to 1 inch is because of that You know if you have the structural system capable of taking the architectural finishes and service functions will be seriously disturbed that is why buildings are designed for smaller displacement,

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High Performance Concrete (HPC)

High Performance Concrete (HPC)

High Performance Concrete (HPC)
 

High-Performance Concrete (HPC)

➤ The Performance Requirements of Hardened concrete or high-performance concrete are more or less well defined With respect to Shape, finish, strength, durability, shrinkage, and creep,
➤To achieve these objectives economically, the fresh concrete in addition to having a suitable composition in terms of quality and quantity of the materials should satisfy a number of requirements from the mixing stage till it is transported, placed in a framework and compacted,
 

Definition of high performance concrete➤

➤ High-performance concrete (HPC) can be defined as concrete that possesses high strength, work-ability, density, low permeability and resistance to chemical attack,
HPC is concrete that has been designed to be more durable and if necessary stronger than conventional concrete,
 

Introduction of high performance concrete➤

➤Deterioration, long term poor performance, and inadequate resistance to hostile environment led to the accelerated research into microstructure of concrete and hence the evaluation of high-performance concrete,
➤ Long-term performance of structures has become vital to the economics of a nation,
➤As a result, new materials and composites have been developed,
➤Today concrete structures with high compressive strength of 140 MPa are being built in United States and Europe,
 

Benefits for the designer➤

➤ The benefits of high-performance concrete to the designers are much more than those of high-strength concrete,
➤Designers can design smaller cross-sections,
➤Slender members,
➤High Elastic modulus,
➤Initial high early strength,
➤Rapid attainment of final creep level,
 

Benefits for the producer of high-performance concrete➤

 
➤In the Production of high-performance concrete Quality control in terms of raw materials and finished products is imperative,
➤Increased quality control leads to increased profitability and productivity of usual concrete,
How is high-performance concrete made?

Mechanism of high performance concrete➤

Under compressive loads, failure in normal concrete occurs either➯
 
➱Within the hydrated cement paste,
➱Along the interface between the cement paste and aggregate particle,
➱Aggregate,
 
To improve the strength and other properties it is necessary to strengthen these weak areas,
 

Improving the strength of hydrated cement paste can be done by➮ 

➤Reducing the water binder ratio and hence the usage of super plasticizing admixtures having high range water reduction capacity,
➤Using supplementary Cementitious materials,
 

Increasing the strength of the transition zone➮

➤Reducing water and cement ratio.
➤Using supplementary cementitious materials.
➤Ensuring proper coating of aggregates with cement paste.
➤Use of smaller-sized aggregates leads to homogeneous distribution of water.
 

 Aggregate Failure➱

➤Due to Aggregates failure Cement paste material remains intact.
➤Failure plane propagates through the Coarse aggregate particles.
 
What are the two typical ingredients used in high performance concrete?

Ingredients of High performance concrete➤

➤Cement (O.P.C, blended Cements etc.)
➤Water,
➤Aggregates
➮Fine Aggregates
➮Coarse Aggregates
➤Admixtures
➤Supplementary Cementitious materials(Fly Ash, Silica fume, GGBS, etc.)
 

Cement➱

Cement Selection is critical to rheology and compressive strength.
 
➤Fineness of Cement
 
➮ From the Strength point of view, the finer the cement the better the concrete,
➮ From the Rheological point of view, The finer the cement the more reactive concrete,
 

Water➱

➱Chilled water is added to reduce the concrete temperature,
➱ice flakes are added as a part of mixing water,
 

Aggregate➱ 

Strength of aggregate depends on the nature of the parent rock Prepared from.
 
➱Avoid rocks with weak cleavage planes of severely weathered.
➱Fine aggregates should be rounded and uniformly graded.
 

Admixtures➱

Super plasticiser➮ 
 
➱Disperses Cement Particles within the mix.
➱Reduces the Amount of mixed water.
➱Controls the rheology of very low water/binder ratio mixtures.
➱solve slump loss problems.

Supplementary Cementitious materials➱

➱Ground Granulated blast-furnace slag.
➱Fly ash (low Calcium, high calcium).
➱Silica flume or micro silica.
➱ Natural pozzolana (meta kaolin, rice husk ash).
 

Aspects of High-performance concrete in fresh state➱

➱Batching and mixing.
➱Tests in fresh HPC concrete.
➱Placement and Compaction.
 

Batching and Mixing➱

➱Batching of individual materials must be accurate.
➱Longer mixing time is required to ensure homogeneity as the mix is usually sticky.
➱Mixing time of 90 seconds is recommended.
 

Tests on Fresh HPC Concrete➱

Following tests on fresh high-performance concrete is carried out.
 
➱Slump / Flow table 
➱Air content 
➱Temperature
➱Unit weight
➱Setting time of mix
➱Bleeding
➱Slump retention and Pump-ability 
 

Placement and compaction of High performance concrete➱

➱Concrete mix is carried from the batching plant with the help of transit mixtures.
➱Method of placing is mostly by pumping.
➱Compaction is by both External as well as internal means.
 

Test on Hardened high performance concrete➱

The following tests are carried out on hardened high-performance concrete.
 
➱Compressive strength (Cube and Cylinder)
➱Split Tensile strength.
➱Modulus of elasticity.
➱Water permeability.
➱Rapid Chloride penetration test(RCPT)
 

Durability of HPC➱

➱Durability of Concrete can be defined as the resistance of concrete to deteriorating influences which may be inside the concrete itself or which may be present in the environment to which it is exposed.
➱ The durability of Concrete Largely depends on the ease with which fluids, both liquids and gases, can enter into and move through the concrete. This property is known as the permeability of concrete.
High Performance Concrete (HPC)

The durability of HPC: Carbonation➱                                          ͏͏͏

➱ In Presence of Moisture CO2 Present in Air reacts with Ca(OH)2  to form CaCO3.
➱ Carbonation causes the reduction in pH of pore water from between 12.6 to 13.5 to about 9.
➱ Steel embedded in concrete forms a thin passivity layer of oxide which remains only with high pH.
➱ As The pH reduces the oxide layer is removed and the corrosion of steel starts, its volume increases and creates tensile stresses in concrete.

Durability of HPC: Chloride attack➱

➱ The primary action in chloride attack is the corrosion of steel and consequently damage to surrounding concrete.
➱ As long as the oxide film on steel is present, The steel remains intact.
➱ Chloride ions destroy the film and in the presence of water and oxygen corrosion occurs.
➱ Corrosion does not occur in dry or fully submerged concrete but occurs in alternate wetting and drying and relative humidity of 70-80 %.
➱ Chlorides can be present in concrete through the use of contaminated aggregates, seawater or chlorides in admixture.
➱ According to I.S.  total chloride content in cement should not exceed 0.05% by mass of cement.
➱ I.S. 456-2000 states that total Chloride content in concrete should not exceed .4 and .6 kg/cum for pre-stressed and reinforced/plain concrete containing embedded metal respectively.
High Performance Concrete (HPC)

Durability of HPC: Sulphate attack➱ 

➱ Common sulphates present in soil and groundwater are sodium, potassium, magnesium, and calcium.
➱ Sulphates present in solution react with hydrated cement paste.
➱ Sodium sulphate attacks Ca(OH)2 and gypsum is deposited, Ca(OH)2 Can Also be completely leached out.
➱ Magnesium sulphate attacks calcium silicate, calcium aluminate hydrates and also Ca(OH)2.
➱ Calcium sulphate attacks calcium aluminate hydrate (C3A) forming ettringite.
➱ Ettringnite formed has a higher volume and causes expansion in concrete.

Durability of HPC: Alkali Aggregate Reactivity➱

➱ Reaction between active silica constituents of aggregates and alkali in cement forms alkali-silicate gels in planes of weakness or either in pores or surface of aggregates.
➱ The reaction starts with an attack on siliceous minerals in aggregates by alkaline hydroxide in pore water derived from the alkalies(Na2O or K2O) in cement.
➱This gel is of unlimited swelling type, absorbs water and causes an increase in volume.
High Performance Concrete (HPC)

Development Of HPC Mixes➱ 

➱ Computing the Target strength.
➱ Estimating mixing water content.
➱ Calculation of water to cementitious material ratio.
➱ Selection of percentage of SCM.
➱ Selection of fine to total aggregate ratio.
➱ Calculation of aggregate contents.
➱ Selection of Superplasticiser dosage.
➱ Trial mix and testing.

Development Of HPC Mixes with Fly Ash➱

Approx mixing water for 20 mm aggregate and 100 mm slump

Fly Ash Content  Water kg/Cum
30 155+5 or 155-5
40 150+5 or 150-5
50 145+5 or 145-5
 
➱ Selection of fine to total aggregate – Normally 25-40 % is used depending upon the grade of concrete, nominal size of aggregate and workability required.
➱ Calculate aggregate content based on the absolute volume method.
High Performance Concrete (HPC)
 
High Performance Concrete (HPC)
 

Where is high performance concrete used?
What is high performance concrete used for?

All Necessary Factors➱

 
Specifications for Bandra – Warli Sea Link Project➱
 
 ➱ Selection of water/binder ratio sufficient enough to achieve the target strength with special consideration from a durability point of view.
➱ Use of Supplementary Cementitious material together with a low water to binder ratio to make concrete structure more dense with a minimum volume of capillary pores, hence making it more durable.
➱ Water content in the mix is required to be kept at the lowest practical so as to minimize drying Shrinkage.
➱ Limiting the heat generation (especially in mass concrete) by keeping the total OPC content in the mix to the minimum required.
➱ Use of high-range water reduction admixtures to achieve the required workability.
High Performance Concrete (HPC)
Bandra-Warli Sea link under construction
High Performance Concrete (HPC)
bandra-Warli Sea link

Project Specification➯

Grade of Concrete- M60
Target Strength – 74 MPa
Max.Water / Binder ratio – < .35
Permeability – Less than 25 mm as per DIN 1048

Ingredients (Kg/cum) Earlier Mix Modified mix
Cement  320 300
Fly ash  110 (25 %) 196 (40 %)
Micro silica 43 40
Total cementitious material  473 536
total water  127 136
W/C ratio  .27 .25
Coarse aggregate  947 1077
fine aggregate 947 750
Admixture 15.1 10.9
 
Properties  Earlier Mix Modified Mix % (Modified/Earlier)
Compressive Strength (MPa)
3 days 39.8 39.3 98.7 %
7 days 56.9 54.8 96.3 %
28 days 78.1 74.7 95.6 %
56 days 79.4 80.9 101.9 %
91 days 80.9 92.2 113.9 %
 
Durability properties  Field results
Water Permeability @ 28 days NIL
RCPT @ 28 days 657 Coulombs
RCPT @ 91 days 432 Coulombs
 
High Performance Concrete (HPC)
 
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