Research on improving the durability performance of damaged concrete based on ultra high performance concrete repair

Abstract

This article uses ultra-high performance concrete (UHPC) to repair damaged concrete and analyzes the durability performance of the repaired concrete. Among them, three erosion solutions with a mass concentration of 2.8% NaCl + 0.29% Na₂SO₄, 5% NaCl, and 5% NaCl + 10% Na₂SO₄ were designed to soak the concrete specimens for 1 to 3 months. Taking the SWC test group as an example, when the concrete test block undergoes 30 dry wet cycles and the erosion depth is 20 mm, the difference in chloride ion concentration under different diffusion dimensions is not significant. After 90 dry wet cycles, at a depth of 20 mm, the chloride ion concentration inside the concrete in the three-dimensional diffusion state reached 3 times that of one-dimensional diffusion, and the chloride ion concentration in the two-dimensional diffusion state also reached 2 times that of one-dimensional diffusion. At a depth of 30 mm, a small amount of chloride ion content was also found in the two-dimensional diffusion and three-dimensional diffusion.