The first step is to figure out how to reduce the 300 million tons of virgin aggregate materials mined in this country every year. The U.S. currently recycles 90% of used asphalt, but still uses a large percentage of virgin materials in the recycled mix. The question is, can pavement be made with 90% recycled asphalt, or does it have to be less than 40% or even 20% to get a roadbed that lasts? What happens to the modifiers that bind these materials over time? How recyclable are the recycled materials?
The cost of building a road is not reflected fully in the price of materials, Gardner adds. The total cost of mining virgin materials, for instance, involves not only the cost of materials and labor, but also the environmental cost at the mining site, the environmental costs (such as air pollution and its associated health care costs) of transporting these materials to the building site, and the environmental costs of building the equipment to mine and transport material and build the roads.
To account for these hidden costs, the RMRC created a computer model that Gardners Ph.D. student Alberta Birdie Carpenter uses to capture the full environmental, social and material costs of road-building. The model was recently road-tested in the Pittsburgh region to help identify the significant influence that materials recycling can have on regional air quality, hazardous waste generation, greenhouse gas emissions and other environmental impacts.
Research and development of better ways to re-build inf
|Contact: Debra JohnyBear|
University of New Hampshire