All of asphalt will carry by dump trucks , which are tight , clean and smooth metal beds that have been sprayed with a minimum amount of soapy water or lime solution to prevent the mixture from adhering to the beds . After application of any release agent, the bed is tipped for drain off any excess or pooled material.
2
Speading & Finishing Equipment
The equipment for spreading and finishing is approved mechanical self –powered pavers, capable of spreading and finishing the mixture true to the line , and cross section required on the Drawings or as directed by the Engineer. The pavers is equipped with hoppers and distributing augers to place the mixture evenly in front of the pavers screed automatically at a constant height with augers running nearly 100% of the time . the augers is equipped with a short reverse auger or “kicker” to push material under the auger drive box . the auger is in good , condition and extent to within 30 cm of the screed end gates.
3
Compacting Equipment
One static vibratory tandem steel wheel roller for break down rolling of a type , wheel width and diameter , weight , and operating condition.
One pneumatic – tired roller for intermediate rolling. this roller has at least 7 smooth tread tires of equal size and diameter . the tires is spaced so that the following tires will cover gaps between adjacent tires and is a weight and operating condition.
One tandem steel wheel roller for finish rolling, of a type ,wheel width and diameter , weight and operating condition.
Applying water to pneumatic –tired rollers is not recommended. Each tired is equipped with a spring –loaded scraper to remove any buildup of material. All of the motioned rollers are self-propelled.
The mixture will deliver to the pavers at the best temperature limit.
4
Placing of Mixture
Preparation of surface:Immediately before placing the bituminous mixture ,the surface will clean of loose or deleterious material by sweeping with a power broom supplement by hand booming if necessary.
After the surface has been appropriately cleaned , the surface will have a Tack Coat applied as per these specifications or as directed by the Engineer.
5
Spreading & Finishing
Before the start of paving operation the screed of the pavers will be heated. The mixture is going to be spread and struck off to the grade, elevation, and cross section shape required. The mixture will be prevented from collecting and cooling at the sides of the hopper or elsewhere in the pavers.
6
Compaction
Immediately after the mixture has been spread and struck off, the surface will be checked and any inequalities adjusted.
Rolling of the mix consist of three separate operation as followos,varitation from which authorized by the site Engineer.
Time after Lying
Initial or breakdown rolling
0-10 mins
Secondary or intermediate rolling
10-20mins
Final or finish rolling
20-45 mins
a. The initial and the final or finish rolling will be done with steel-wheeled rollers. The secondary or intermediate rolling will be done with a pneumatic tired roller. The breakdown roller will operate with the drive roll nearest the pavers.
b. Transfers joints will be rolled first and in the initial rolling will be rolled transversely using boards of the required thickness at the edge of the pavment to provide for off-the-pavement movement of the roller .
c. Rolling will start longitudinally at the joint and then at the outside edge and will proceed parallel with the road centerline towards the center of the pavment,except that on super –elevated curves rolling will begin at the low side and progress toward the high side.
d. The speed of the rollers will be at all times slow enough to avoid displacement of the hot mixture, and to concentrate comp active effort.
e. Rolling will progress continuously as may be necessary to obtain uniform compaction while the mixture is in workable condition and until all roller marks and other irregularities are eliminated .
7
Joints
IBoth longitudinal and transverse joints in successive will be staggered so as not to be one above the other . Transverses joints will be staggered a minimum of 25 cm and will be straight and perpendicular to the direction of paving.
Alternate methods for longitudinal joint construction may be directed by the site Engineer.
