Yu Demei, Feng Chao, Fu Tengfei, Shen Aiqin
College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, China.
School of Highway, Chang'an University, Xi'an 710064, China.
Materials (Basel). 2022 Mar 10;15(6):2036. doi: 10.3390/ma15062036.
The existence of chloride ions, sulfate ions, and vehicle dynamic loads may lead to a shortened service life and premature failure of the road and bridge structures in northwestern China. Immersed in a dual-salt solution while simultaneously applying cyclic flexural loads, the free chloride ion concentration and erosion depth in concrete specimens were measured. The influence of the sulfate concentration on the apparent surface chloride concentration () and apparent diffusion coefficient () was studied. An exponential model was used to fit the , and the influence of sulfate concentration on the was analyzed. The result showed that cyclic loading and solution concentration were two primary factors affecting chloride diffusion. Meanwhile, compared with the emersion conditions, dynamic loading would induce significantly accelerated chloride ion penetration. Under the coupling effect of sulfate and dynamic loading, as the sulfate concentration increased, the chloride ion concentration and erosion depth were both decreased. The existence of sulfate ions improved the chloride ion penetration resistance of concrete. The results provide insight in designing concrete in regions where multiple salt ingression (sulfate and chloride) is a major durability issue of the structures.
氯离子、硫酸根离子的存在以及车辆动荷载可能会导致中国西北地区道路和桥梁结构的使用寿命缩短和过早破坏。将混凝土试件浸泡在双盐溶液中，同时施加循环弯曲荷载，测量混凝土试件中的游离氯离子浓度和侵蚀深度。研究了硫酸根浓度对表观表面氯离子浓度（）和表观扩散系数（）的影响。采用指数模型拟合，分析了硫酸根浓度对的影响。结果表明，循环荷载和溶液浓度是影响氯离子扩散的两个主要因素。同时，与浸泡条件相比，动荷载会显著加速氯离子渗透。在硫酸根与动荷载的耦合作用下，随着硫酸根浓度的增加，氯离子浓度和侵蚀深度均降低。硫酸根离子的存在提高了混凝土的抗氯离子渗透性能。研究结果为在多种盐分侵入（硫酸根和氯离子）是结构耐久性主要问题的地区设计混凝土提供了参考。
