Mechanical and durability characteristics of SCC incorporating recycled aggregate and steel slag

Abstract

This study presents a detailed investigation of the properties of self-compacting concrete (SCC) incorporating steel slag-based granulated slag aggregates (GSA) and recycled aggregates (RA) as substitutes for M-sand (MS) and natural coarse aggregates (NCA), respectively. NCA was replaced with coarse recycled aggregate (CRA) at levels of 20%, 25%, 30%, and 35% in SCC mixtures containing either MS or GSA as the fine aggregate. Cement was blended with ground granulated blast-furnace slag (GGBFS) and metakaolin (MK). The evaluated fresh properties were within the limits specified by EFNARC. The compressive strength of MS- and GSA-based SCC ranged from 24.2 to 35.9 MPa and from 27.4 to 38.9 MPa at 28 and 56 days, respectively. Increasing the curing period from 28 to 56 days enhanced the compressive strength by 3.4–13.2%. Acid immersion resulted in mass losses of 0.4–2.4% and reductions in compressive strength of 2.60–7.52%. The maximum water absorption (WA) of the SCC mixtures remained below 3%. Increasing the CRA content increased the permeability from 21.9 to 24.8 mm. No significant variations in WA, acid resistance, or permeability were observed in GSA-based SCC containing up to 30% CRA. Overall, the experimental results demonstrated that GSA-based SCC exhibited better performance than MS-based SCC.