Study on mechanical properties of cost-effective polyvinyl alcohol engineered cementitious composites (PVA-ECC)

Engineered cementitious composites (ECC) which shows prominent tensile ductility and toughness, and fine multiple cracking, meets the high requirements of safety and durability in developing sustainable infrastructures. Currently, the cost of oiled polyvinyl alcohol (PVA) fiber widely used in ECC is very high. The price of regular unoiled PVA fiber is relatively lower, however, the tensile ductility of unoiled PVA-ECC may be limited. Based upon the micromechanics model, the feasibility of use of unoiled PVA fibers and hybrid PVA fibers in ECC were studied, and the mix proportion was redesigned through parametric analysis. The four-point bending test, uniaxial tensile test and uniaxial compressive test were carried out to characterize the mechanical behavior of ECC with 21 mix proportions. According to the cost and performance of PVA-ECC, three typical mixes were proposed: M7 with low cost, relatively low tensile ductility and reinforced by unoiled PVA fibers, M17 with moderate cost, relatively high tensile ductility and reinforced by hybrid PVA fibers and M21 with high cost, high tensile ductility and reinforced by oiled PVA fibers. In practical applications, the determination of mix depends on the structural performance requirements.