基于多维Cl^(-)侵蚀寿命预测的C40混凝土保护层厚度设计

Design of C40 Concrete Protective Layer Thickness Based on Multi-dimensional Cl^(-)Erosion Life Prediction

为研究混凝土在盐碱环境中的多维Cl^(-)扩散规律及对应的保护层厚度设计,利用ANSYS有限元建模,选取了4个不同的时间节点,研究了不同时间下混凝土中Cl^(-)浓度分布情况,并预测不同扩散维度下混凝土的耐久性服役寿命,从而建立了混凝土保护层厚度与设计寿命的映射关系。研究结果表明:相比1维扩散,2维与3维扩散在混凝土表层的Cl^(-)浓度与扩散深度较大,2维与3维扩散深度分别为1维扩散的1.47倍与1.84倍;Cl^(-)侵蚀环境中混凝土耐久性服役寿命较短,在1维Cl^(-)侵蚀下寿命不足20年,而在3维侵蚀下寿命不足10年。对于C40混凝土在50年设计使用寿命下,1维、2维及3维Cl^(-)扩散状态下保护层厚度分别为50 mm、60 mm和68 mm。

In order to study the multi-dimensional Cl^(-)diffusion law of concrete in saline-alkali environment and the design of the corresponding protective layer thickness,ANSYS finite element modeling was used to select four different time nodes to study the Cl^(-)concentration distribution in concrete at different times,and to predict the durability service life of concrete under different diffusion dimensions.Thus,the mapping relationship between the thickness of the concrete protective layer and the design life is established.The results show that compared with 1-D diffusion,the Cl^(-)concentration and diffusion depth of 2-D and 3-D diffusion on the concrete surface are larger,and the depth of 2-D and 3-D diffusion is 1.47 times and 1.84 times of 1-D diffusion,respectively.The durability service life of concrete in the Cl^(-)erosion environment is short,which is less than 20 years under 1-D Cl^(-)erosion and less than 10 years under 3-D erosion.For C40 concrete under the design service life of 50 years,the thickness of the protective layer in the 1-D,2-D and 3-D Cl^(-)diffusion state is 50 mm,60 mm and 68 mm,respectively.