Optimization of mechanical properties of corn stalk ash and fiber reinforced cement mortar

Corn stalk ash and fibers, as agricultural waste materials, offer significant potential for sustainable applications in cementitious composites. This study investigates the effects of corn stalk ash content, fiber content, and water-to-cement ratio on the mechanical properties of cement mortar. A Box-Behnken design (BBD) within the Response Surface Methodology (RSM) framework was employed to evaluate the impact of these factors and their interactions on flexural and compressive strengths. The results indicate that the water-to-cement ratio is the most influential factor, followed by fiber content, while ash content has a relatively minor impact. Notably, the interaction between fiber content and water-to-cement ratio exhibited a strong synergistic effect. The optimized mix design—comprising 10% corn stalk ash, 0.4% fiber content, and a water-to-cement ratio of 0.45–0.5—achieved flexural and compressive strengths of 8.7 MPa and 54 MPa, respectively. Experimental validation demonstrated high model accuracy, with relative errors below 1%. This study underscores the feasibility of utilizing agricultural waste in cement-based materials, contributing to the advancement of sustainable construction practices.