Optimized potential performance of slag sand in cement mortar through micro-mechanical and durability investigation

The study aims to reduce the dumping of industrial waste and recycle it in the construction sector for its various structural elements by addressing a significant environmental concern to minimize natural resources. Alternative sustainable aggregate resources are necessary in the construction industry due to the depletion of natural resources and to satisfy the rising demand for natural aggregates. Slag sand, a new refined product obtained from the JSW steel plant during steel production, is tested for its feasibility in replacing river sand and manufactured sand. An experimental analysis of cement mortar's microstructure, mechanical, and durability properties is investigated by replacing sand with 0, 25, 50, 75, and 100% slag sand, considering a grade of 1:3 mix. Results show a considerable improvement in strength performance with slag sand. It performed better in mechanical and microstructure properties at 50% optimum replacement of slag sand, revealing the formation of calcium silicate hydrate, resulting in a denser structure. The UPV test results also conform to the maximum compressive strength for optimum mix. It was also observed from the density characteristics of sand-based mortar mix that the density of the cement mortar reduces gradually. A similar trend is noticed in the impact resistance of mortar mixes. The more carbonation in the mortar specimens, the more incomplete hydration leads to the formation of pores and brittleness, thus reducing the increased strength after 50% inclusion of slag sand. Interestingly, industrial waste can be used potentially in construction activities as it results in improved strength attainment with age. Thus, recycling this slag sand in cement mortar contributes to efficient and economical usage, promoting appropriate waste management by approaching sustainable construction.