Abstract
•Enhancing the efficiency of steel fibers in high-performance concrete.•Promoting the utilization of rice husk ash (RHA) to valorize agro-wastes.•Comparison between the mechanical performance of SFRC with RHA and MS.•The efficiency of fiber was better at low levels of RHA and MS.•The modification effect of MS was superior compared to RHA.
To improve the fiber-matrix bond and enhance the macro-mechanical performance of SFRC, this study is focused on the modification of the cement matrix by using two eco-friendly supplementary cementitious materials (SCMs), rice husk ash (RHA) and micro-silica (MS). The modification effects of SCMs on the steel fibers were observed and characterized by conducting several macro-mechanical tests i.e., compressive strength, splitting tensile strength, and load-deflection behavior. Besides that, ultrasonic pulse velocity, water absorption, and chloride migration tests were performed to characterize the durability of modified SFRC mixes. The results showed that the incorporation of RHA and MS at low levels notably enhanced the efficiency of steel fibers under splitting tensile and flexural strength testing. SFRC made with 7.5% MS and 7.5% RHA showed 79% and 96% more flexural strength than plain concrete (PC), respectively. Whereas SFRC experienced 14% and 26% further improvement in flexural toughness with the addition of 7.5% RHA and 7.5% MS, respectively. The addition of 7.5% and 12.5% RHA showed a beneficial effect on the resistance of SFRC against the penetration of chloride ions and water. The results of this study confirmed the synergistic interaction of steel fiber and SCMs.