Compressive and flexural properties of ultra-high performance fiber-reinforced cementitious composite: The effect of coarse aggregate

Abstract The inclusion of coarse aggregate in the cementitious composite can improve the mechanical property and simultaneously curb the cement demand thus lowering the production cost in concrete built infrastructure. This study investigates the effects of different coarse aggregate types and contents on the compressive and flexural properties of ultra-high performance fiber-reinforced cementitious composite (UHPFRC). Four types of coarse aggregates (granite, basalt, limestone and steel slag) and four contents denoted by the volume of mortar replacement (0%, 15%, 30% and 40%) are the main variables. The test results have shown a significant increase in compressive strength and elastic modulus of UHPFRC after moderate addition of coarse aggregate with only an expense of a slight reduction in the flexural strength and post-peak ductility. The aggregate types having different stiffness can be effective in either increasing the compressive strength or enhancing the post-peak ductility, which is also true for the increase in aggregate content. With respect to the flexural behavior, it is found that coarse aggregate type significantly affects the flexural strength and equivalent flexural strength ratio, whilst no considerable variations in the first crack strength is observed. Furthermore, an analytical model is proposed to generate the complete compressive stress-strain curves of UHPFRC.