Investigation of chloride ion diffusion in shotcrete under bending loading
Wang Jiabin1,2 Niu Ditao1,3
1. Xi′an University of Architecture and Technology, Xi′an 710055, China;
2. Xi′an Technological University, Xi′an 710021, China;
3. National Key Laboratory of Green Building in West China, Xi′an University of Architecture and Technology, Xi′an 710055, China
Abstract：By using spring four-point bending loading method, the chloride ion diffusion in shotcrete under the bending loading was studied. Based on the Fick′s second law, the variation law of chloride ion diffusion coefficient of shotcrete was analyzed. By comparing the distributions of chloride ion in molded concrete, in shotcrete and in steel fiber reinforced shotcrete (SFRS), the effects of steel fibers and molding method on chloride ion diffusion were investigated. The results show that the bending stress has an important influence on the chloride ion diffusion in shotcrete. Due to the bending stress, the distribution of pore structure and the number and depth of microcracks can be changed, which may affect the chloride ion diffusion rate in shotcrete. On the side of tension zone, the content of chloride ion may increase with the increase of bending stress ratio. However, the rule is opposite on the side of compression zone. At the same stress ratio, shotcrete has the largest diffusion coefficient, and the relationship between molded concrete and SFRS is related to the stress state, stress ratio, steel fiber and molding method.
