NATURAL AGGREGATE SUBSTITUTION BY STEEL SLAG WASTE FOR CONCRETE MANUFACTURING

Abstract

The release of steel slag into the environment has substantial repercussions, simultaneously affecting both the ecosystem and the economy. Therefore, the management and recovery of this waste demand careful consideration. In the context of the circular economy, this study aims to explore the feasibility of utilizing steel slag waste as a substitute aggregate for natural coarse and fine aggregates in the production of high-quality concrete. Throughout this research, concrete mixtures were developed by varying natural aggregate substitution rates with steel slag waste at 0, 25, 50, 75, and 100%. Comprehensive tests, encompassing physical, mineralogical, chemical, and mechanical analyses, were conducted on the steel slag waste to ascertain its primary technical properties. In all mixtures incorporating steel slag waste, compressive strength tests consistently revealed values surpassing those of the reference concrete. Notably, there were improvements of approximately 12% for coarse aggregate substitution and 32% for sand substitution. Assessments of flexural strength at 7 and 28 days underscored the substantial positive influence of fine and coarse aggregate substitution, especially at a 50% fine aggregate replacement, contributing significantly to enhanced flexural strength compared to conventional concrete. Furthermore, laboratory examinations indicated that the 28-day compressive and flexural strength, as well as water absorption of concrete, increased with slag content, albeit at the expense of reduced workability. Ultimately, the findings demonstrate the effective utilization of slag as a replacement for natural aggregates, maintaining the compressive and flexural strength of the concrete.