SUITABILITY OF RECYCLED CONCRETE AGGREGATE FOR USE IN BS 5328 DESIGNATED MIXES.

The paper describes a study undertaken to examine the suitability of recycled concrete aggregate (RCA) for use in BS 5328 designated mixes. The results for the aggregate characteristics showed that plain as well as reinforced demolished concrete debris can be crushed using existing plant to provide RCA of physical properties that satisfy the current BS 882 requirements. The density of both fine and coarse RCA was found to be lower than that of natural aggregate (NA) and water absorption was three to six times higher. The results showed that original strength of the recycled concrete had a negligible effect on the fresh properties of the designated concrete mixes produced. Those mixes with high proportions of RCA were found to be harsh or less cohesive and exhibited higher bleeding, but this could be overcome using a filler material, such as coarse PFA. (A)