16.3 EQUIPMENT USED FOR TRANSPORTATION,
LAYDOWN, AND COMPACTION
16.3.1 TRUCKS
For long-distance hauling, trucks should be insulated. A canvas should be used to hold heat, keep
light rain showers off the HMA, and keep away dust. Truck beds should be clean, and trucks should
be loaded properly to avoid segregation. Typically, trucks should be loaded in the front first, then
in the back, and finally in the middle. Sometimes a material transfer vehicle is used to receive the
mix from the truck, store it, remix it with augers, and then transfer it to the paver. This helps in
maintaining the uniformity of the mix and also in maintaining constant paving operations. Note
that prior to the placement of an HMA layer, a tack coat of emulsion (at the rate of 0.01–0.2 gal/
square yard, depending on the type of surface) is generally applied on the existing surface to help
bond it with the new layer (Figure 16.11). The surface must be cleaned prior to the application of the
tack coat. Figure 16.12 shows a view of an HMA paving site with the different equipment.