EFFECT OF LOW-COST PVA FIBERS ON THE MECHANICAL PROPERTIES OF ENGINEERED CEMENTITIOUS COMPOSITES

Engineered Cementitious Composites (ECC) have attracted much attention because of its high toughness and multiple cracking characteristics. However, the use of imported PVA fibers in the past has resulted in high price which limited large scale engineering applications. To reduce the cost and achieve the localization of raw materials, it is necessary to study the influence of low-cost domestic PVA fibers on the mechanical properties of ECCs. The mechanical properties of two kinds of domestic low-cost PVA-ECCs were studied by macroscopic and mesoscopic experiments, including uniaxial tensile, compression, three-point bending and single-crack tensile tests. The microscopic features such as the fiber dispersion was investigated by the tests and SEM. The results show that the low-cost domestic fibers have good dispersibility in the matrix. Although the fiber bridging complementary energy, maximum bridging stress and the PSH index are lower than those of imported fibers, they meet the energy and strength criteria. The tensile strain capacity of the relatively poor fiber A reached 2.52%, 3.34% and 3.08% at 3 d, 7 d and 28 d, respectively, which exhibited good stress hardening behavior and saturated multi-cracking characteristics and satisfies the application requirements of ECC.