Crack Resistance and Toughening Mechanism of Nano-SiO2 Reinforced PVA Fiber Cement-based Composites in Steel Bridge Engineering

: With the development of steel bridge engineering science, PVA fiber cement-based composite materials are gradually being explored and applied. Because of its high ductility and toughness, it has received extensive attention from academia and industry. Cement-based composite materials are essentially made of cement-related raw materials, which are mixed with various other materials to form composite materials. Incorporating Nano-SiO 2 into it can effectively improve the structural performance and durability of cement-based composite materials. Therefore, the purpose of this paper is to study the crack resistance and toughness mechanism of Nano-SiO 2 reinforced PVA fiber cement-based composites in steel bridge engineering. This paper first determined the design plan of the mix ratio of the Nano-SiO 2 PVA fiber cement-based composite material, and then used the composite beam composed of PVA fiber concrete and existing concrete as the experimental object. The test data shows that when the amount of hydrophilic nanopowder SiO 2 reaches 1%, the compressive strength of the mortar at the second and third day of age is increased. At this time, the higher the content of hydrophilic nanopowder SiO 2 , the higher its compressive and flexural strength. However, when the content is greater than 1.0%, the content of hydrophilic nano-powder SiO 2 has no great influence on the improvement of its compressive strength.