|Bituminous Concrete layer|
ASPHALT,ASPHALT CONCRETE, BITUMINOUS CONCRETE LAYERS
What is Asphalt Concrete ?:➤
What is the difference between bituminous concrete and asphalt?
What is BM and BC?
ACTIVITIES IN ASPHALT WORK ➤
What is DBM and BC?
What is BC layer in road construction?
MATERIALS IN ASPHALT CONRETE ➤
PAVING OPERATION ➤
CHECKS BEFORE PAVING(PRE-PAVING ACTIVITY)➱
➤Paver Level Sensor To be Set For Required Level Given Of String Wire Or Average Beams,
CHECKS DURING PAVING ➱
➤Total Area Should Be covered With Tack Coat,
➤Start The Unloading Of Truck into the paver, After checking The Temperature Of Mix,
➤Loose Thickness Should Be Checked With Thickness Gauge Regularly in some Interval of Time,and Length,
➤Check The Camber with line rope , taper.
➤If any Segregated area is Found spread the fines with shovels prior to rolling,
➤Check for Rolling Should Be done As per Rolling pattern,
SURFACE FINISH ➤
➤The tolerance in level should be in between +/- 6 mm,
➤The Core Density should be 92 % of Lab GMM.
➤Road Unevenness index shall be less than 2000 mm per kilometre for road works,
➤The Mix Binder Content shall be +/- .3% of Designed OBC,
➤Surface Regularity DBM, BC shall be +/- 6 mm , +/- 3 mm,
TRANSVERSE JOINT MATCHING➤
LONGITUDINAL JOINTS MATCHING➤
CHECKS DURING PRODUCTION➤
➤Maintain The Bitumen Temperature as 150 degree Celsius,
➤Maintain the aggregate Temperature as 160 to 170 degree Celsius,
➤Ensure The Mix temperature should be Between 140 to 150 degree Celsius,
➤Clean the Vehicles Neatly,
➤Load The mix to Trucks and Cover with Tarpaulins and Hauled to site,
➤ Check The temperature at plant,site and record it,
➱The Rolling process should start 12 to 15 inches from the lower unsupported edge as the un-compacted edge provides the initial confinement during the first pass,thus minimizing lateral movement of the mix. ⇩
➱Succeeding pass should move to the edge once the central portion of the spread is compacted to some degree because the mix will support the roller and allow the edge to be compacted without lateral movement,
Following some important machines are required for Laying of Asphalt concrete , Bituminous Concrete Layer ,
3➮Pneumatic Tyre Rollers
PNEUMATIC TYRE ROLLER➤
What is pneumatic tyre roller ?
➤The Pneumatic tire roller(PTR) is tire mounted roller having smooth tire surface,
➤It’s Weight can be adjusted according to the requirement(Generally 16 to 18 mt for bituminous layers rolling is used),➤It is used for Compaction and kneading action,
➤Longitudinal movement of the mix doesn’t take place unless the dia. is very less,
➤Horizontal forces is minimized with the use of larger diameter.
➤The movement of mix under the tire tends to be lateral,
➤The humps created during breakdown are of no significance and can be cleared in subsequent pass,
➤Under normal conditions, when the roller is on top of a firm mat it has no horizontal thrust as the tire flattens on the bottom which permits an 100 % vertical force,