Concrete/asphalt recyclers recovered as much as 140 million tons of concrete and at least 15 million tons of asphalt in 2005, according to a recently released evaluation of a survey of Construction Materials Recycling Association (CMRA) members, making concrete the most recycled material in North America by weight.
 
In addition, it was estimated that the approximately 250 mixed construction and demolition recycling plants in the United States annually recover 28 million tons of materials.
 
The CMRA survey also found recycling rates for the two types of plants are equally impressive. Concrete/asphalt recycling plants recycle 99 percent of what they take in, and for the difficult mixed C&D recycling plants, they are recovering 71 percent of their C&D feedstock, according to the survey.
 
“This report shows that, by weight, concrete is the most recycled material in the country, and the 99 percent recycling rate shows the efficiency of those plants processing it,” says William Turley, executive director of the CMRA and associate publisher of Construction & Demolition Recycling. “And equally impressive is that the operators of mixed C&D plants are able to recover 28 million tons from what is basically the residuals of what construction and demolition contractors generate.”

The survey was sent to all CMRA recycling members and 950 other C&D recyclers. Twenty-eight percent of the members responded. CMRA member Gershman, Brickner & Bratton Inc. (GBB) compiled the data and combined it with its own information on the size of the C&D industry to provide the estimate of how many tons of C&D were recycled and to determine the recycling rates for the two segments.
 
“This was the first scientific attempt to determine how much concrete is recycled since our first attempt in 1997,” says Turley. “At that time we estimated 107 million tons were recycled. But this review was more thorough and rigorous than our first and confirms what many C&D experts already felt, that concrete is recycled more than any other material.”
 
The CMRA study concluded that 155 million tons of recycled aggregates are produced by the C&D recycling industry every year. This includes an estimated 130 million to 140 million tons of concrete and 15 million to 25 million tons of asphalt. The latter numbers are not the total annual numbers of asphalt recycled, which is projected to be 90 million tons, according to the National Asphalt Pavement Association. The CMRA data does not include highway millings and contractor’s specific full-depth removal project work.
 
This recent study was also the first ever to look at what mixed C&D plants recover from their operations. A large part of what they take in comes from demolition projects, where the demolition contractors have recovered almost all of the easily recyclable materials such as metals and the recycler has to deal with the chaff. The study estimated that about 25 percent of the products produced by C&D recyclers are concrete and asphalt, 20 percent are wood products and 17 percent is currently an alternative daily cover (ADC) used for landfills.
 
There are no official estimates for the overall size of the C&D material stream. The CMRA estimates that 325 million tons of C&D are generated every year, and that includes the material generated in road and bridge construction/demolition projects. In 1998 a U.S. Environmental Protection Agency (EPA) report estimated that 136 million tons of building-related C&D were generated in 1996. Currently the agency is trying to update that number as well as estimate how much road and bridge debris is generated, but no date has been announced for the release of those figures.