Repercussion of Steel Mill Scale on Concrete Compressive Strength as Fine Aggregate Replacement
This study is on the utilization of supplementary aggregate materials to prepare a concrete with the adequate strength. The main properties of concrete, such as strength, durability and serviceability, depend mainly on the properties and quality of the materials that are used in preparing it. Therefore, the use of waste materials, such as steel mill scale, in concrete may have positive or negative effect. Mill scale is a flaky hazardous solid waste formed on the steel’s surface during the steel manufacturing processes. Steel mill scale can be used in conventional concrete as a partial replacement for fine aggregate. The percentage replacement may vary from 0 to 100 percent depending on the grade of the concrete. Investigation was carried out to study the effect of five replacements levels; where the fine aggregate was replaced by steel mill scale by 15%, 30%, 50% and 100%. Compressive strength of cube specimens with the above replacements were checked for the curing period of 7, 14, 28 and 56 days and compared with normal mix (with 100% fine aggregate). The strength gain was observed in steel mill scale concrete with increase in the curing periods. Two mixes attained higher strength from that of normal concrete with fine aggregate replacements about 15% and 30%. One mix with fine aggregate replacement of 50%, gained strength nearer to normal concrete.