When laying a mat alongside a previously laid mat, a matching joint must be made between the two mats. It is preferable to match the mats before the first mat has set up whenever possible. If this is to be done, do not let the roller on the 6 inches to 1 foot (152.4 to 304.8 mm) of the first mat closest to the joint, then roll the joint with the second mat.
To make the joint, the edge of the screed should usually overlap the first mat 1 to 2 inches (25.4 to 50.8 mm) and be practically flush with it. If the first mat has been rolled, be sure to allow for compaction of the second mat. Roll the joint as soon as possible.
The quality of a transverse joint is highly dependent on the preparation made for the joint when ending the first mat (See "Ending a Mat" on page 4-21). The edge of the first mat should be vertical so that a good bond can be made.
If the joint is to be made before the first mat has cooled, do not roll the last two yards (1.8 meters) of the mat. When ready to make the joint, raise the screed and back the paver toward the first mat until the edge of the mat is 3 or 4 inches (76.2 to 101.6 mm) in front of the screed, and lower the screed onto the mat. If the thickness controls have been changed since ending the first mat, adjust them with the screed resting on the mat, then fill the screw conveyor with asphalt mix and start paving as usual.
If the joint is to be made with a mat already compacted, use the same procedure, but be sure to allow for compaction of the new mat when setting the screed thickness controls.
The procedure for laying asphalt around a manhole depends on the course to be laid. If the top course is to be laid, the surface of the mat will usually be higher than the top of the manhole so the only thing that must be watched is the grade at which the screed rides to be sure the screed clears the manhole.
If a binder course is to be laid, the screed will not clear the manhole so the screed will have to be raised until it passes the manhole. A mark alongside the mat to show the position of the manhole will help the operator judge the position of the manhole when it is underneath the machine.
If the position of the manhole will cause the wheels of the machine to pass over the manhole and grade control is not being used, the thickness controls must be used to keep the screed at the correct height. If the manhole rises more than about 1 inch (25.4 mm) above the surface the tires are traveling on, a ramp should be made for the wheels to travel onto and off the manhole. A simple method to make a ramp is to use asphalt from the hopper of the machine.
Any asphalt placed on the top of the manhole should be removed before the roller passes over it.