The use of steel slag aggregate to enhance the mechanical properties of recycled aggregate concrete and retain the environment

Waste materials, such as demolished concrete rubbles and steel slag, are dumped in landfills. Such action destroys the environment. Recycling these materials and using them as coarse aggregate in new concrete mixes would eliminate the problem. The paper summarizes a two-stage research conducted to evaluate the use of the two environmentally harmful materials in concrete. Stage 1 studies the effect of using recycled concrete aggregate (RCA) or steel slag aggregate (SSA) on the properties of normal concrete. First, RCA and SSA properties have been determined and compared with those of normal aggregates. Later, RCA and SSA were introduced in concrete mixes. In these mixes, natural coarse aggregate is partly or totally replaced by RCA or SSA. Results show that the use of RCA or SSA has an adverse effect on the workability and air content of fresh concrete. While RCA resulted in reduction in the mechanical properties of concrete, SSA enhanced these properties. In order to enhance the properties of RAC so that it can be used safely in structural concrete, the RCA has been partially replaced by SSA in stage 2 of the research. Results show that this is possible. (C) 2013 Elsevier Ltd. All rights reserved.