Effect of micro-silica on the physical, tensile, and load-deflection characteristics of micro fiber-reinforced high-performance concrete (HPC)

Abstract

In this research, the influence of micro-silica (MS) was studied on the tensile and flexural behavior of micro-carbon fiber (MCF) reinforced HPC. For this purpose, a total of twelve concrete mixes were designed incorporating six different doses of MCF (at 0%, 0.15%, 0.25%, 0.5%, 0.75% and 1%) with and without MS.The examined properties included compressive strength, splitting tensile strength, load-deflection behavior, ultrasonic pulse velocity, and water absorption. It was found that without MS inclusion, MCF shows a nominal contribution to the mechanical properties. However, the efficiency of MCF incorporation improved phenomenally due to MS addition. The incorporation of MCF at an optimum dose (0.5–0.75% volume fraction) showed 32% and 6% net improvements in modulus of rupture with and without MS, respectively. The micro-filler and pozzolanic effect of MS particles enhanced the bond strength and efficiency of micro-filaments of MCF. MS incorporation delayed the fracture of fiber-reinforced HPC under flexural loading.