Effect of rice husk ash as partial replacement of ordinary Portland cement in ultra-high-performance glass concrete

Abstract

Ultra-high-performance concrete (UHPC) is a high-tech concrete whose excellent mechanical and durability characteristics are ascribed to the homogeneity and high packing density of its matrix. However, due to the high contents of cement and silica fume usually necessaries for achieving this packing density, UHPC's final cost and carbon-footprint are far higher than standard concretes. Therefore, over the last few years, the spotlight of UHPC’s research has focused sharply on the analysis of locally available supplementary cementitious materials as partial replacement of cement and silica fume. This article presents an investigation to analyze the effect of rice husk ash (RHA) as partial substitution of cement in a previously optimized mixture of recycled-glass-UHPC by means of several statistical tools. Cementitious materials employed in this research involved silica fume, limestone powder, recycled glass powder and ordinary Portland cement (OPC). Based on the results, it can be concluded that RHA addition in the optimized glass UPHC yields to a significant decrease in the workability of concrete and a slight decrease of compressive strength. Results also demonstrated the high interaction between the RHA and water contents, which could be ascribed to the water absorption and internal curing provided by RHA particles.