Effect of limestone and granite stone powder on properties of cement-treated clay composites and their socioeconomic and environmental impacts

•Limestone particle size does not impact consistency limits of cement-treated clay.•The effect of limestone on UCS of cement-treated clay depends on curing time.•Limestone particle size does not significantly affect the UCS of cement-treated clay.•Stone powder reuse reduces cement and water usage, embodied emissions, energy, and costs. Large volumes of stone powder, i.e., limestone and granite waste are produced annually. When reused in cement-treated clay, the granite stone powder particle size affected the composites' unconfined compressive strength (UCS). However, limestone's effect on cement-treated clay has yet to be addressed comprehensively. This paper presents the effects of uncalcined limestone of different sizes on the particle size distribution, consistency indices, and the UCS of cement-treated clay composites at curing periods of 1, 3, 7, and 28 days. A comparison between the performance of cement-treated clay-limestone, cement-treated clay-granite powder composites, and cement-treated clay and their effect on sustainable construction is also presented. After 1 and 3 days of curing, the UCS of cement-treated clay-limestone composites was higher than the cement-treated clay control sample. However, at 7 and 28 days, the cement-treated clay-limestone composites possessed similar UCS to the cement-treated clay control sample regardless of their particle size. Cement-treated clay-granite powder composites are stronger than cement-treated clay-limestone composites. Regardless of the performance differences, both limestone and granite powder can be reused in cement-treated clay without significant loss in UCS and provide environmental benefits such as reduced cement usage and embodied airborne emissions, energy, and abiotic depletion, among other factors.