Sustainable self-curing concrete using PEG-400 and pumice for water-scarce environments

The increasing demand for water-efficient construction has strengthened interest in self-curing concrete (SCC), particularly for arid and water-scarce environments. This study evaluates the combined use of polyethylene glycol-400 (PEG-400) and pumice as an internal-curing strategy under ambient curing. Four SCC mixtures were prepared with pumice replacing 0%, 20%, 40%, and 60% of conventional coarse aggregate, while PEG-400 was maintained at 1% by mass of cement. Workability, compressive strength, splitting tensile strength, flexural strength, water absorption, sorptivity, rapid chloride permeability, chemical resistance, and microstructural characteristics were investigated. The 20% pumice mixture gave the highest reported mechanical performance among the four investigated replacement levels, with strength increases of approximately 10–17% relative to the 0% pumice mixture. Durability comparisons were performed for the 0% and 20% mixtures and indicated lower water absorption, sorptivity, and chloride-ion transport for the 20% mixture. XRD, FTIR, SEM, and EDAX observations were consistent with enhanced hydration and pore refinement at moderate pumice replacement. Because PEG-400 was fixed at 1% and PEG-only, pumice-only, and factorial control mixtures were not included, the study does not statistically establish a PEG–pumice interaction or synergy; the results instead identify the best-performing composition among the investigated mixtures. The findings support the potential of pumice-based self-curing SCC for water-scarce construction, while highlighting the need for replicate-level statistical analysis, broader durability testing, and intermediate replacement levels in future work.