Effects of recycled aggregates on properties of plastic concrete using densified mixture design algorithm (DMDA)

Abstract

This study explored the effects of the recycled fine and coarse aggregates (RFA and RCA) on the properties of the plastic concrete with mixing proportions designed by densified mixture design algorithm (DMDA). The recycled aggregates partially replaced the natural aggregates by 10–50% volume and the fly ash was used to minimize the voids. The results showed that, as the replacement ratio of RFA was increased from 10% to 50%, the workability, bleeding and water permeability were increased, but the strength was decreased. With RCA, the workability, bleeding, and water permeability were increased, but the strength were decreased and slightly recovered at an optimal replacement ratio of 30% and 40%. All the changed properties were attributed to the packing effect more than the water absorption and the hydration. The DMDA helps to produce qualified plastic concrete with high consistency, low strength, and low permeability in the presence of recycled aggregates.