钢筋非均匀锈蚀下混凝土保护层锈胀开裂分析

    Analysis of rust-jacking cracking of concrete cover under non-uniform corrosion of reinforcing bars

    • 摘要: 目前针对钢筋混凝土构件锈胀开裂的分析多根据加速试验得到,其锈胀开裂模型基于均匀锈蚀得到,然而这与真实环境下锈蚀钢筋混凝土构件裂缝发展存在一定差异,进而影响到开裂时间。本文基于弹性力学理论建立了钢筋非均匀锈胀开裂力学模型,该模型建立了钢筋锈蚀率与非均匀锈蚀形态、锈蚀产物体系膨胀系数、锈蚀产物弹性模量、保护层厚度、混凝土弹模、钢筋直径等参数间的关系。以海洋环境暴露试验为研究对象,通过数值模拟方法对比分析真实环境下混凝土开裂规律、锈胀开裂力学模型的准确性以及锈胀开裂关键参数敏感性分析。结果发现锈蚀产物体积膨胀系数及弹性模量对混凝土锈胀开裂宽度及时间有较大影响,并给出海洋环境下钢筋锈蚀产物体积膨胀系数及弹性模量的推荐取值范围。

       

      Abstract: At present, the analyses of rust-jacking cracking of reinforced concrete components are mostly obtained based on accelerated tests, and the rust-jacking cracking models are mostly derived from uniform corrosion However, this approach exhibits certain discrepancies when compared to the actual crack propagation observed in corroded reinforced concrete components in real-world environment, thereby affecting the accuracy of cracking time predictions. Based on the theory of elastic mechanics, this paper established a mechanical model of non-uniform rust-jacking cracking of reinforcing bars. This model established the relationship between the corrosion rate of reinforcing bars and parameters, including the non-uniform corrosion morphology, expansion coefficient of rust products, elastic modulus of rust products, thickness of the concrete cover, concrete elastic modulus, and the diameter of reinforcing bars. Using marine environmental exposure tests as the research object, the cracking behavior of concrete under real environmental conditions was analyzed. The accuracy of the proposed mechanical model and the sensitivity of key rust expansion cracking parameters were evaluated through numerical simulation methods. The results indicated that the volume expansion coefficient and the elastic modulus of rust products significantly influence both the width and initiation time of rust-jacking cracking. Accordingly, recommended value ranges for these two key parameters under marine environmental conditions were provided..

       

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