Performance and Durability of Chemically Activated Lime‐Based Cement Blended With Rice Husk Ash

Lime–pozzolana binders offer a low‐carbon alternative to conventional materials; however, their practical application is limited by slow strength development and insufficient durability, particularly under aggressive chemical environments. In addition, existing studies on chemical activation have largely focused on OPC‐based systems, with limited attention to lime‐based binders and their durability performance. This study investigates the effect of chemical activation on the performance and durability of lime–rice husk ash (RHA) mortars. The objective was to evaluate how sodium hydroxide (NaOH) and sodium sulfate (Na 2 SO 4 ) influence compressive strength, porosity, and resistance to sulfuric acid attack of lime mortars. Physicochemical characterization confirmed that the RHA contained 94.95% SiO 2 with high amorphous content and strong pozzolanic reactivity (> 60% conductivity loss). Results showed that RHA incorporation improved lime mortar performance, while chemical activation significantly enhanced these properties. NaOH activation increased compressive strength by 132%, compared to 53% for Na 2 SO 4 , relative to the non‐activated system. Porosity decreased progressively across the systems, with the lowest values observed in NaOH‐activated mortars. Under acid exposure, all RHA‐containing mortars outperformed pure lime, which disintegrated completely. Strength and mass losses were lower in activated systems, particularly with NaOH. Deterioration was more severe in 3% H 2 SO 4 than in a 0.5% solution. The findings indicate that chemical activation improves the short‐term performance of lime–RHA mortars, although reaction products were not directly quantified. These results highlight the potential of chemically activated lime–RHA mortars as sustainable construction materials, particularly in resource‐constrained regions.