Ji Yongcheng, Liu Wenchao, Jia Yanmin, Li Wei
School of Civil Engineering, Northeast Forestry University, Harbin 150040, China.
Materials (Basel). 2021 Nov 13;14(22):6856. doi: 10.3390/ma14226856.
In order to study the durability behavior of CFRP (carbon fiber reinforced polymer) reinforced concrete, three category specimens (plain, partially reinforced, and fully reinforced) were selected to investigate its performance variation concerning chlorine salt and salt-freeze coupled environment, which included the microscopic examination, the distribution of chloride ion concentration, and the compressive properties. By observing the microscopic of the specimens, the surface and cross-section corrosion deterioration was examined with increasing exposure time, and the physical behavior of CFRP and core concrete were discussed. The chloride ion diffusion test exerted that the chloride ion concentration in plain specimens is at least 200 times higher than that of fully reinforced specimens. Therefore, the effectiveness of CFRP reinforcement will be proved to effectively hinder the penetration of chloride ions into the core section. The formula of the time-dependent effect of concrete diffusivity with salt-freeze coupling effect was presented and its accuracy verified. A time-varying finite element model of chloride ion distribution was established by using ABAQUS software. It can be seen from the axial compression test that the strength loss rate of three categories of specimens was varied when subjected to the corrosion environment. Therefore, it is proved that CFRP reinforcement can effectively reduce the deterioration of the specimen's mechanical properties caused by the exposure environment. The research results can provide technical reference for applying the CFRP strengthened concrete in a severe salt-freeze environment.
为研究碳纤维增强聚合物（CFRP）加固混凝土的耐久性，选取了三类试件（素混凝土、部分加固和全加固），以研究其在氯盐和盐冻耦合环境下的性能变化，包括微观检查、氯离子浓度分布和抗压性能。通过观察试件的微观结构，随着暴露时间的增加，检查了表面和横截面的腐蚀劣化情况，并讨论了CFRP和核心混凝土的物理性能。氯离子扩散试验表明，素混凝土试件中的氯离子浓度至少比全加固试件高200倍。因此，将证明CFRP加固的有效性在于能有效阻碍氯离子渗入核心截面。给出了混凝土扩散系数随盐冻耦合效应的时变公式，并验证了其准确性。利用ABAQUS软件建立了氯离子分布的时变有限元模型。从轴向压缩试验可以看出，三类试件在腐蚀环境下的强度损失率各不相同。因此，证明了CFRP加固可以有效减少暴露环境对试件力学性能的劣化。研究结果可为在严酷盐冻环境中应用CFRP加固混凝土提供技术参考。
