Effect of Hybrid Fibers on Flexural and Tensile Properties of Ultrahigh Performance Fiber-Reinforced Cementitious Composites: Experiments and Calculation

Abstract

This paper addresses effects of hybrid fibers on the flexural and tensile properties of ultrahigh performance fiber-reinforced cementitious composites (UHPFRCC). The workability, compressive strength, flexural strength, and uniaxial tensile properties of designed UHPFRCCs were investigated. The results indicate that UHPFRCC containing 1.5% long steel fiber and 0.5% short steel fiber exhibits the best flexural property. Flexural strength was decreased with the increased amount of plastic fibers, resulting from inhomogeneous distribution of steel fibers. UHPFRCCs with larger amounts of short steel fibers show higher ultimate tensile strength. In addition, first-cracking tensile strength and ultimate tensile strength of UHPFRCC with plastic fibers were reduced but the strain-hardening process was enhanced. An analytical model was utilized to predict the ultimate tensile strength of hybrid fiber-reinforced UHPFRCC; theoretical calculations and the experimental results were in good agreement, which was used to explain the effect of hybrid fibers on the ultimate tensile strength of UHPFRCC. Various hybridization designs of fibers and the high volume of mineral admixtures can significantly reduce the environmental impact and develop a novel cleaner construction product with excellent materials properties.