Effect of self-compacting concrete added with concrete debris and steel slag aggregate

Abstract

Recycled Aggregate (RA) and Slag Aggregate (SA) have been used as alternative course materials in concrete for decades in the building industry in order to achieve sustainability. The use is currently acknowledged as a viable alternative to coarse aggregate, and it is a promising material for reducing the environmental effect of slag waste and concrete debris. The experimental investigation on Self Consolidating Concrete (SCC) created with fractional replacement on RA and SA is discussed in this work. The slump test, V-funnel, U-box, and L-box tests are performed on SCC in its fresh condition with substitutes. The mechanical characteristics are measured at the ages of 7 and 28 days to determine the effective usage level of replacement. Cube-compressive strength, cylinder-tensile strength, prism and beam flexural strength are all tested, and the results are compared to NC and SCC values. According to the results of the tests, the studied values of concrete characteristics with a higher percentage of RA and SA replacement are lower than those of reference mixes. In grade-M30 concrete with W/C optimal, the aggregate replacement is done as a mix of both RA and SA together with steel slag 7 percent as a partial substitution for cement. Microstructure analysis is used to examine the mineral composition and C-H-S gel formation of the specimen with a pretty optimal value. According to SEM-EDs analysis, adding steel slag to the mix results in the formation of additional C-S-H gel, which aids in the attainment of fair strength and compressive strength values that are within the range of slag activity index; however, mineral element subsistence differs from the reference mix. Nevertheless, the findings are adequate for practical use and cost-effectiveness, with acceptable strength attributes.