Effect of utilizing peanut husk ash on the properties of ultra-high strength concrete

Cement production is classified as a highly contaminating process in recent decades, and numerous efforts have been accomplished to reduce cement used in construction for more sustainability. Cement complementary materials make an ecological impact on its manufacturing, in which the cement production cost can be reduced. In this investigation, peanut husk ash (PHA), as a newly abundant agro-industrial waste ash, was used as a substitution for ordinary Portland cement (OPC) in ultra-high-strength concrete (UHSC). PHA was heat-treated at various temperatures of 400, 500, 600, and 700 °C and utilized with substitution rates of 2.5%, 5.0%, and 7.5%. In addition, recycled granite was utilized as a coarse aggregate in UHSC. Thirteen mixes were prepared and tested to examine the fresh, mechanical, physical, and microstructure characteristics of the proposed UHSC. Concrete slump, compressive strength, indirect tensile strength, flexural strength, bond strength, modulus of elasticity, and water permeability were the measurements in this study. In addition, microstructure characteristics were obtained through X-ray diffraction analysis (XRD), thermo gravimetric analysis (TGA), and scanning electron microscope (SEM). The acquired outcomes revealed that utilizing 5% PHA as a partial substitution of OPC achieved high mechanical characteristics, and the optimal temperature for treating the peanut husk ash was 600 °C. The results of this experimental investigation can contribute well to illustrating the effect of utilizing PHA as a novel agricultural waste ash in UHSC to achieve significant financial benefits and a favorable ecological impact.