Tensile properties of PVA and PE fiber reinforced engineered cementitious composites containing coarse silica sand

Abstract

To mitigate the shrinkage of engineered cementitious composites, coarse silica sand has been employed to substitute ultrafine silica sand in recent years. However, for the different matrix strengths and fiber types, the mechanism of coarse silica sand on ECC tensile performance is different. In this paper, coarse silica sand was introduced into PVA fiber (PVA-ECCs) and PE fiber reinforced ECCs (PE-ECCs), and the impact of silica sand with different particle sizes on the tensile properties of PVA-ECCs and PE-ECCs was investigated. Results indicate that a larger size of silica sand leads to more and larger pores and a looser matrix, which is not conducive to fiber dispersion and fiber/matrix interfacial bonding, resulting in a reduction in tensile strength. Additionally, increasing the silica sand particle size can availably decrease the matrix fracture toughness of PE-ECCs, making the matrix more prone to cracking, promoting saturation cracking behavior and increasing tensile strain capacity, whereas PVA-ECCs have the opposite trend. Moreover, microstructural analyses using SEM were conducted to analyze the impact of coarse silica sand and ultrafine silica sand on the tensile behaviors.