海工混凝土氯离子扩散系数随深度的变化规律

Change of chloride diffusion coefficient in marine concrete with depth

氯离子扩散系数是表征氯离子侵入混凝土内部速率的重要参数.基于混凝土在长期服役过程中内部毛细孔结构的演化结果和电化学理论,推导了介质在真实溶液中的扩散方程.理论计算结果表明,混凝土内部氯离子扩散系数随深度的增加而增大.对工程现场混凝土内部氯离子的浓度进行取样检测,计算得出不同深度氯离子扩散系数的变化规律,与现场检测结果变化规律一致.

Chloride diffusion coefficient in concrete is an important parameter for the durability of marine concrete structures, which characterizes the velocity of chloride penetrating into concrete. Based on the evolution of capillary in concrete during the long term service and electrochemical theory, a modified equation is derived in this paper to analyze the chloride diffusion in the real solution. Theoretical results show that the chloride diffusion coefficient of concrete increases with the depth. In addition, the changes of the chloride diffusion coefficient in concrete are calculated according to the chloride concentrations on the surface, which are in good agreement with the results inspected from the field.