Using rice husk ash to imitate the properties of silica fume in high-performance fiber-reinforced concrete (HPFRC): A comprehensive durability and life-cycle evaluation

High-Performance Fiber Reinforced Concrete (HPFRCs) are recognized by a special combination of cementitious composites with high durability, high strength, and deformability. However, due to the high initial price and constrained availability of materials like Silica Fume, its implementation is challenging, particularly in developing countries. In this study, cement was initially replaced by 10%, 20%, and 30% fly ash (FA), respectively. Furthermore, the mix providing maximum compressive strength was then taken to replace the silica fume content at 10, 20, 30 and 40% by RHA, and then steel fiber was also added to optimize the compressive and flexural ductility performance of the specimens. An extensive evaluation of the durability, mechanical, and microstructural characteristics of produced HPFRCs was carried out. In addition, to evaluate the sustainability of produced mixes, a lifecycle evaluation was carried out utilizing the recipe midpoint and endpoint techniques. Test results show that the uniaxial compressive strength was significantly enhanced at RHA concentrations up to 20%. Moreover, the gradual increment of RHA concentration enhanced the durability performance of HPFRCs, as evidenced by a reduction in the sorptivity coefficient of up to 30%. In addition, the Life-cycle analysis (LCA) assessment revealed a significant reduction of crucial environmental factors, such as CO₂ emissions, fine particle discharge, ozone depletion, and land use with the gradual integration of RHA and FA.