Material Characterization and Experimental Design for Concrete Using Steel Slag as Fine Aggregate Replacement

Abstract

Steel slag is produced during the production of steel and has a negative environmental impact due to the disposal of this waste. As part of this study, it has explored the possibility of using steel slag, instead of a conventional sand or other fine aggregate, as a partial replacement for fine aggregates in concrete without a chemical admixture. Concrete mixtures were created with varying amounts of steel slag (0 to 100%, in increments of 10%) substituting for fine aggregates. Based on the initial test results, the concrete with 100% steel slag substitution had an inadequate level of workability and insufficient strength; therefore, it did not meet performance specifications. Based on these findings, it is evident that complete substitutions of steel slag have very limited application in concrete. Experimental testing of concrete mixtures was conducted to assess their fresh and hardened properties using slump, compressive strength, split tensile strength and flexural strength according to relevant IS standards. Results indicate that concrete mixes with lower percentages of partial replacement (i.e. 10%-40% steel slag) outperformed concrete mixes with higher percentages of partial replacement (i.e. 50%-100%). The mixes containing steel slag had good workability and superior mechanical properties relative to the higher percentage mixes. This research supports the conclusion that sustainable (environmentally-friendly) materials, such as steel slag, can be used as an effective substitute for fine aggregates in concrete when used as a partial replacement (up to 40% steel slag). Complete substitution of fine aggregates with steel slag is not advisable.