Hybrid effects of steel fibers, basalt fibers and calcium sulfate on mechanical performance of PVA-ECC containing high-volume fly ash

Abstract

In order to increase the strength and lower the cost, this study experimentally investigated the effects of hooked-end steel fiber, basalt fiber and calcium sulfate on mechanical performance of polyvinyl alcohol (PVA) fiber-based engineered cementitious composite (ECC) containing high-volume fly ash. The uniaxial tensile, compression and four-point bending tests were carried out to characterize the mechanical behavior of each mixture. Scanning Electron Microscopy (SEM) image analysis and X-ray CT scan method were used to study the microstructures and distributions of pores. Test results showed that the ultimate strain capacity increases nearly linearly with the growth of stress performance index except the ECC reinforced with calcium sulfate and PVA. Hybridization with basalt fiber and PVA fiber or steel fiber and PVA fiber is more effective for improving mechanical performance within small deformation. ECC reinforced with calcium sulfate and PVA exhibits improved tensile, compressive and flexural strength while maintaining high ductility. The cost performance considering strength/cost and ductility/cost of hybrid mixtures was also discussed.