Frequently Asked Questions
What is asphalt pavement?
Asphalt pavement a high-quality, thoroughly controlled, engineered material made from aggregate (stone, sand or gravel) using asphalt cement as a binder.
How is asphalt pavement made?
Asphalt pavement is made by heating asphalt cement and mixing it with aggregates and mineral fillers. The asphalt paving mixture is loaded onto trucks for delivery to construction sites or kept in storage silos.
What is asphalt cement?
Asphalt cement is a derivative of crude oil refining that is the binder or glue in the asphalt pavement mixture.
Can asphalt pavements be recycled?
Yes! Asphalt pavement is 100% recyclable and can be made to perform better the second or even the third time around. In fact, it is the most recycled product in the United States, both in terms of tonnage (73 million tons, more than any other material) and in terms of percentage (80 percent of reclaimed asphalt pavement is recycled, a higher percentage than any other substance). That compares to significantly lower percentages of aluminum cans, newsprint, plastic and glass beverage containers, and magazines. Asphalt roads are removed, recrushed, mixed with additional aggregate and fresh asphalt cement, remixed and placed back on the road. The hot mix industry also uses the following recycled materials: slag from the steel making process, roofing shingles, sand from metal casting foundries, and rubber from old tires. Recycling roads not only conserves natural resources and decreases construction time; it saves American taxpayers more than $300 million each year.
How environmentally safe are asphalt plants?
Asphalt plants must meet rigorous standards established by the EPA, Massachusetts DEP and other agencies, but often the individual plants set their own standards that are even more demanding. Recent improvements in asphalt production have made the industry even more environmentally friendly. In fact, after a six year study, the EPA announced in 2002 that asphalt plants are no longer on its list of industries considered major sources of hazardous air pollutants.
Why are so many asphalt plants necessary?
Asphalt pavement material begins to cool as soon as it is mixed. In order to maintain workability at the paving site, and for the highest quality of the finished pavement, the mixing facility (asphalt plant) must be near the paving site.
Is asphalt pavement used only for roads?
No. Asphalt has a variety of uses, including:
- Paving running tracks, airport runways, greenway trails, bicycle and golf cart paths, basketball and tennis courts, reservoirs, and automobile racing tracks.
- Paving cattle feed lots, poultry house floors, barn floors and greenhouse floors.
- Lining surfaces from fish hatcheries to industrial retention ponds.
- Laying rail beds for transit systems.
Is asphalt a sustainable material?
Clearly, it is. In addition to its recyclability, which conserves precious natural resources, asphalt provides long life solutions for pavement construction. Some asphalt pavements reduce noise pollution and alleviate other environmental concerns. And while production of asphalt paving materials has increase by more than 250 percent over the past 40 years, emissions from asphalt plants have dropped by 97 percent or more. Some additional points to consider:
- Asphalt is not soluble or harmful in a water environment. It has been used successfully for many years in fish hatcheries, reservoirs of drinking water for human consumption, and other environmental protection applications.
- Asphalt prevents pollution from getting into water supplies and protects against disease from waste materials. It can be combined with aggregates to form an impermeable layer. Asphalt pavements are effective liners and caps for landfills.