Comparative Assessment of ۶% and ۱۰% Cement-Stabilised Earth Bricks Incorporating Rice Husk Ash for Sustainable Masonry Construction

The increasing demand for sustainable construction materials has intensified interest in the use of agricultural waste as supplementary cementitious materials in earth-based construction. This study comparatively evaluated the performance of compressed stabilised earth bricks (CSEBs) produced with ۶% and ۱۰% cement contents incorporating rice husk ash (RHA) as a partial cement replacement. Rice husk ash replaced cement at levels of ۰–۴۰% by weight of the binder, producing eighteen brick mixtures. The specimens were tested for compressive strength and density at curing ages of ۷, ۲۸, and ۹۰ days. Statistical analyses, including Analysis of Variance (ANOVA), Tukey's Honestly Significant Difference (HSD) test, and quadratic regression analysis, were employed to evaluate the significance of the results and determine the optimum replacement level. Compressive strength increased with curing age for all mixtures, while bricks stabilised with ۱۰% cement consistently outperformed those containing ۶% cement. The highest compressive strength of ۱.۲۸ MPa was achieved at ۲۰% RHA replacement in the ۱۰% cement series, representing a ۲۰.۸% improvement over the control. ANOVA confirmed that RHA replacement significantly influenced compressive strength (p < ۰.۰۵), whereas Tukey HSD identified ۱۵–۲۰% RHA replacement as the optimum range for the ۱۰% cement series. In contrast, the control mixture performed best in the ۶% cement series. Density decreased with increasing RHA content because of the ash's lower specific gravity, producing lighter masonry units. These findings demonstrate that rice husk ash is a viable supplementary cementitious material for sustainable compressed stabilised earth bricks.

کلیدواژه ها:

Compressed stabilised earth bricks ، Rice Husk Ash ، Cement replacement ، Sustainable Construction ، Lateritic soil