Abstract
Different types of recycled aggregates consisting of crushed concrete, recycled rubble stone and crushed clay brick were used as 100% coarse aggregates to prepare concrete mixtures of water/cement ratios of 0.6 and 0.45. Crushed natural dolomite stone was used a control. The various concretes were tested for concrete properties of compressive strength, split tensile strength, the Youngs modulus of elasticity and abrasion resistance. It was found that recycled aggregates reduce the workability of concrete mixtures. Use of recycled aggregates of concrete origin also exhibits reduction in compressive strength and split tensile strength by up to 35%. With high strength concrete mixes of at least 50 MPa, the strength losses reduce to negligible levels in some cases. Crushed brick stones gave much higher split tensile strength than all the other recycled stones. The relationship between elastic moduli and compressive strength for concretes made with normal aggregates does not appear to directly apply to concretes made using recycled aggregates. Crushed brick also gave high abrasion resistance similar to the performance of the control dolomite stone and better than the other recycled aggregates.