| Summary: | The effects of using crushed waste concrete as course aggregates upon compressive strength and durability against to carbonation and sulfate attack were investigated. Waste concrete cubes, which had been tested for compressive strength in compliance with construction specifications, were crushed and utilized as coarse recycled concrete aggregates (RCA) in new concrete. It is important to mention that, in order to simulate the real life conditions, waste concrete with very minimal information about its origin was used in its natural moisture condition. Tests on the aggregates showed that the RCA had lower specific gravity and bulk density, but a higher water absorption capacity than the natural aggregates. The resistance to mechanical actions such as impact and crushing for RCA is also lower. Concrete mixes with water cement ratios ranging from 0.47 to 0.70 were prepared using this RCA as coarse aggregate and tested. From the strength point of view the RCA concrete compared well with natural aggregate concrete. Therefore it could be considered for various potential applications. With respect to resistances to carbonation and sulfate attack the RCA concrete showed comparable performance.
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