Effect of reactive coarse recycled aggregate with different expansion history on alkali silica reactivity and mechanical properties of new concrete

Abstract

Recycled concrete aggregates (RCA) provide an environmentally friendly solution by reducing the depletion of natural resources. This study investigates the impact of the expansion history of RCA on its reactivity with alkalis in newly produced concrete. Parent concrete samples were collected from the RILEM AAR‐4 curing cabinet (60°C and >90% RH) to produce coarse RCA with four different expansion levels (0.00%, 0.05%, 0.12%, and 0.20%). The results show that the expansion levels of the new concrete mixtures decreased as the ASR expansion history of parent concrete increased. The 20‐week compressive strength and elastic modulus of the reactive aggregate concrete containing no mineral admixture and exposed to AAR‐4 test conditions were lower than those of their water‐cured counterparts. However, no decrease was observed in the elastic modulus of concrete mixtures that showed an expansion level lower than 0.03% (the maximum expansion for nonreactive aggregate as recommended by the RILEM AAR‐4 standard).