During the week of September 26, Colony Construction joined in an effort led by the Virginia Transportation Research Council and Virginia Department of Transportation’s Richmond District. This research effort focused on producing asphalt concrete modified with processed plastics. On Sunday, September 26, Colony produced an asphalt mix using recycled plastic fed from a fiber feeder. VTRC sampled materials at the plant while the material was laid on route 732 in Chesterfield County. While the initial roller pattern and control strip did not pass the density specifications, several lessons were learned. First, the asphalt plant temperature was critical. With the addition of plastic, the asphalt mixture was stiffer than the un-modified mix. Second, careful calibration of the fiber feeder is necessary to ensure a consistent flow of plastic. Finally, paving operations were not adversely affected by the plastic-modified mix. As the night progressed, core densities passed; this was done by increasing asphalt temperatures to 325 – 340 when leaving the plant.
On Thursday, September 30, Colony produced a second plastic modified mix. Unlike the first mix, the second mix passed the roller pattern and acceptance cores. The lab testing did show tight air voids. However, this particular plastic was not as stiff as the first trial, making compaction much easier.