DOT is a national leader in the use of recycled asphalt pavement (RAP). By incorporating recycled content, the City saves on new material and the costs associated with transport and landfill fees. With RAP, yesterday’s pavement becomes today’s streets as old paving materials get removed from City streets during routine resurfacing operations. The milled material is then reprocessed and reconstituted with new materials before use in subsequent paving. The new Harper Street Asphalt Plant will allow DOT to increase its use of RAP. By producing more recycled asphalt, the City will avoid two million miles of annual truck trips that are used to carry milled asphalt to landfills – reducing congestion, pollution and wear and tear on our streets. The new asphalt plant will increase the amount of City-produced asphalt from 50 percent of the asphalt used by the City to approximately 75 percent and will improve efficiency in City's efforts to restore streets and roadways citywide.
DOT also uses other techniques to green its street resurfacing operations. The Agency is currently piloting the use of warm mix asphalt. Traditional asphalt must be heated to 300–325 degrees, and then quickly transported to the work site. However, DOT has recently been experimenting with warm mix asphalt technology that only requires heating to 200, and can be applied at even cooler temperatures. Warm-mix asphalt is relatively new to the industry and New York City is one of the first cities to actively test it.
Widespread use of warm mix asphalt would decrease emissions, fumes, and odors both at asphalt plants and at resurfacing work sites, and would reduce the amount of energy needed for asphalt production. In addition, it would allow for greater RAP content, possibly up to 60%. It would also extend the paving season into the colder winter months. For DOT, a longer paving seasons means better roads, quicker response time for pothole repair, expanded job opportunities and a general improvement in overall street maintenance. Over the last year, DOT used warm mix asphalt to resurface two low volume streets in Queens. One site was laid in the dead of winter, the other in the heat of summer. Thus far both sites are holding up well. DOT will continue to monitor their progress and will assess opportunities for expanded warm mix use.
DOT will resurface roads using warm mix asphalt at two new test locations this season, then evaluate it in one year to see how they hold up under different driving conditions. If successful, warm mix could become the standard for asphalt production at the two municipally owned plants, which together will supply 75% of the asphalt used in City operations, much of it recycled.