CONCRETE RECYCLING

One of the more interesting new concepts that is gaining interest throughout the country is that of recycling old concrete pavements for aggregate in new construction. Recycling is consistent with the American Concrete Pavement Association (ACPA) econocrete concept, which encourages the use of recycled concrete for subbases, composite pavements, and full-depth pavements. The Federal Highway Administration has endorsed this program and at the present time has a national evaluation program on the recycling of old concrete pavements. Research by the U.S. Army Corps of Engineers indicates that the recycling of an old concrete pavement can actually enhance or improve the original aggregate, thus providing longer life than was possibly attained in the initial pavement. The depletion of supplies of high-grade concrete aggregates in certain regions, the need for better methods of solid-waste disposal, and energy conservation efforts have led to this accelerating interest in recycled concrete. Recycling of old concrete is feasible and should be considered whenever good aggregates are not available locally or when aggregate costs are excessive or where the costs of removing and wasting the old pavement are in excess of what the cost would be for recycling that material for new aggregate. In 1970, aggregates produced in the United States totaled 1.8 billion tons. The highway industry used 47 percent of this, or approximately 800 million tons. It is estimated that, by 1985, production of aggregates will reach 4 billion tons/year and that highways will use 50 percent or 2 billion tons/year. Of the various materials used in highway construction, aggregates constitute one of the major elements of cost-between 21 and 30 percent of the cost of all materials and supplies and between 10 and 14 percent of the total construction cost (excluding the cost of right-of-way and engineering). Recycled concrete can be used as an aggregate base or subbase for pavement, or these bases can be cement treated with soil-cement techniques. It can be used in econocrete subbases (lean concrete) by using concrete mixing plants and slipform pavers. Recycled concrete can also be used as aggregates in new concrete pavement if tests of new concrete made with crushed-concrete aggregate indicate acceptable strength and durability. (Author)

Media Info

  • Features: Photos;
  • Pagination: p. 6-10
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00319346
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Dec 30 1980 12:00AM