硫酸盐侵蚀混凝土劣化机理及力学性能退化模型研究

西部大开发、一带一路以及粤港澳大湾区等国家级战略的提出必将推动大量混凝土结构基础设施的建设，但这些地区属于硫酸盐侵蚀高风险地区，因硫酸盐侵蚀而导致混凝土结构早期失效的现象屡有发生。目前硫酸盐侵蚀混凝土的膨胀劣化机理一直尚未明确，且由于混凝土截面侵蚀的不均匀性使得以各向同性假定为基础的混凝土本构关系并不能直接应用于侵蚀混凝土结构的安全评定。针对上述问题本项目在以下几个方面展开系统研究：探讨干湿循环下硫酸根离子的传输机制，建立考虑扩散-对流-化学反应的干湿循环下硫酸根离子的传输模型；明确硫酸盐侵蚀环境下混凝土的膨胀机理及膨胀变形的计算方法，建立硫酸盐侵蚀混凝土的力学性能劣化模型；给出定义侵蚀区域的硫酸盐侵蚀指标，建立混凝土硫酸盐侵蚀区域的力学性能演化方程，并展开硫酸盐侵蚀环境下混凝土构件的承载力退化模型研究。该项目研究成果可为硫酸盐侵蚀环境下混凝土结构的耐久性寿命分析提供基础数据和方法支持。

With proposing of western development, the belt and road initiative, and the Guangdong-Hong Kong-Macao greater bay area, it will surely promote the construction of a larger number of concrete structure infrastructure. However, these areas are at a high risk of sulfate attack, early failures of concrete structures due to sulfate attack occur occasionally. At present, the expansion deterioration mechanism of sulfate attacking concrete has not been clarified. And due to the heterogeneity of attacked concrete cross-section, the constitutive relationship of attacked concrete based on the assumption of isotropy cannot be directly applied to the safety assessment of concrete structures under sulfate attack. Aiming at these problems, this project carries out systematic research in the following aspects: The transmission mechanism of sulfate ions in concrete under wetting-drying cycle is researched, and a transport model of sulfate ions is established with considering diffusion–advection-chemical reaction under wetting-drying cycle and sulfate attack; The deterioration mechanism and calculation method of expansion are studied and then a deterioration model of the mechanical property of concrete under sulfate attack is established; The sulfate attack index to determine the attacked area is given, then the evolution equation of mechanical properties of sulfate attacked concrete area is built. This research will provide the basic data and method support for the durability life analysis of concrete structures under sulfate aggressive environment.