Compressive strength and water absorption of concrete containing recycled concrete aggregate treated by portland cement – fly ash – sodium sulfate slurry

Abstract

The present study focuses on investigating compressive strength and water absorption of concrete containing recycled concrete aggregate (RCA) treated with a slurry of Portland cement – fly ash – sodium sulfate (Na₂SO₄), to eliminate the exploitation of natural crushed stone and to promote the utilization of construction waste, towards the sustainable concrete industry. The crushed stone was replaced with RCA at levels of 25% and 50% by volume of coarse aggregates. The results showed that the concretes with 25% and 50% replacements with treated RCA by cement – fly ash – Na₂SO₄ slurry (25TR24N and 50TR24N) showed the improved compressive strength by 9.8% and 12.9% than the concrete with untreated RCA (25UR and 50UR), respectively, and they reached 92–96% compared to the control concrete with 100% crushed stone (0R). The water absorption of concrete with treated RCA was reduced by 44.4–51.9% compared to the concrete with untreated RCA and increased by 2.8–34.0% compared to the control concrete with 100% crushed stone.