疲劳作用对混凝土中氯离子扩散系数影响的研究

摘要

采用两种应力水平和四种循环次数，通过轴向压缩的疲劳荷载形式，使混凝土试件获得不同的损伤量。应用超声探伤、电化学阻抗谱的方法判断混凝土的疲劳损伤程度。利用电迁移加速方法，进行氯离子扩散试验，测定混凝土的氯离子扩散系数。最终得到疲劳损伤量与混凝土氯离子扩散系数之间的关系。结果表明：超声波速和阻抗谱低频容抗弧压扁度可以作为表征混凝土疲劳损伤的指标；随着疲劳损伤的增加，混凝土中氯离子的扩散系数增大。%Concrete specimens of different damage quantity were obtained by compressive fatigue load which adopted two kinds of stress level and four kinds of cycle index respectively.And the damage degree was evaluated by means of Ultrasonic Inspection and Elec-trochemical Impedance Spectroscopy.Chloride diffusion coefficient was obtained by the chloride diffusion test which was conducted by means of electro migration acceleration test and then relationship between the damage quantity and the concrete chloride diffusion coeffi-cient was established.The test results showed that ultrasonic velocity and impedance spectrum low frequency capacitive reactance arc flatten-ing could used as the concrete fatigue damage index and chloride diffusion coefficient increased with the increasing of the damage degree.