Source: Construction Materials Recycling Association, Aurora, Ill.
The utilization of recycled concrete aggregate (RCA) as an unbound base product in the highway environment is extensively examined in a new Construction Materials Recycling Association white paper, prepared especially for highway engineers and their federal, state and local agency colleagues.
CMRA estimates that about 140 million tons of concrete are recycled annually in the U.S., road base the most common end use. “Recycled Concrete Aggregate: A Sustainable Choice for Unbound Base” looks at all aspects of RCA’s use in this market, from incoming material, processing, specifications, pros and cons, and cost advantages. It also includes the results of a survey where respondents from 38 state highway departments of transportation note how they use the material.
According to the white paper, RCA is currently being used to some degree in the vast majority of the state DOT, and has proven to be both a viable and valuable alternative to the use of virgin aggregates for base courses. “The performance is equal to, if not better than, virgin aggregate base course when used appropriately,” author Cecil Jones contends. “Significant research has been conducted and published for over 10 years. An AASHTO specification has been in place since 2002. Potential concerns, including precipitates, leachates, durability testing and the existence of asphalt pavement and brick have been addressed.”
Jones, president of Diversified Engineering Services, is the retired chief materials engineer for North Carolina Department of Transportation, and past AASHTO Task Force On Recycled Materials chair. He is familiar with the barriers RCA has faced and what questions DOT personnel want answered before they will approve a recycled product for use in roads. “Recycled Concrete Aggregate: A Sustainable Choice for Unbound Base” is available to CMRA members and highway engineers at any agency level free of charge. — CMRA, 630/585-7530; [email protected]