带裂缝混凝土氯离子扩散作用试验研究及数值模拟

摘要

Process of chloride ion diffusion in concrete with cracks is studied to accurately assess durability performance of concrete structure with cracks.Preparation of cracks with nondestructive method is proposed,which can produce cracks in internal concrete or on its side face effectively.Chlorine salt solution immersion experiments on the concrete with cracks is conducted.It is studied on the chloride ion diffusion effect of specimen with single slit and double slits,and revised chloride ion diffusion coefficient,and simulating chloride ion diffusion process of concrete with cracks.Research results show that the chloride ion diffusion will occur along or perpendicular to the cracking direction,and decreasing of the water cement ratio,resistivity to chloride ion diffusion in cement mortar specimens increased significantly.In a specific range,increasing cracks spacing,the chloride ion diffusion interaction between double slits obviously decreases.And simulation results in ANSYS are in good agreement with those data obtained in test.%为了准确评估带裂缝工作混凝土结构的耐久性能,针对氯离子在带裂缝混凝土中的扩散过程进行研究.提出了无损制备裂缝的方法,可高效易行地在混凝土侧面及内部产生裂缝.对带裂缝的水泥砂浆试件进行氯盐溶液浸泡试验,深入研究了单缝和双缝试件中氯离子的扩散作用,修正了氯离子的扩散系数,并对带裂缝混凝土的氯离子扩散过程进行了数值模拟.研究结果表明:氯离子会沿裂缝发展方向及垂直于裂缝发展方向扩散,随着水灰比的减小,砂浆试件的抗氯离子扩散性能明显提高,在一定范围内,当裂缝间距增大,双缝间的氯离子扩散交互影响作用明显减小,ANSYS软件的模拟结果与试验数据吻合良好.