损伤对混凝土氯离子渗透性能影响的试验研究

Experimental study on the effects of damage on the chloridion permeability of concrete

结构微裂纹的存在会对混凝土渗透性产生一定的影响。通过对两种混凝土的劈裂试验和带损伤混凝土的氯离子渗透试验,研究了微裂隙对混凝土氯离子渗透性能的影响。通过劈裂试验获得对应不同COD值的损伤,并进一步分析损伤与主要的抗渗性能指标即氯离子扩散系数D之间的关系。结果可知:水泥浆强度和骨料的种类及级配是影响混凝土抗裂性能的重要因素;劈裂残余损伤CODr值在25μm范围内对混凝土氯离子渗透性能的劣化影响不大;随着CODr值的增加,氯离子扩散系数变化率β大致呈递增趋势。

Micro-crack in concrete can affect the permeability of concrete in a certain extent.The effect of micro-crack on the chloridion permeability of concrete is focused.The split tests for two different concrete specimen and the chloridion permeable tests for cracked concrete specimen are carried out.Damage with different crack width COD is acquired by split tests,and the relationship between crack width and chloridion diffusion coefficient D is studied.The test results show that strength of cement paste, sort and grate of aggregate have significant impacts on the cracking of concrete;the residual displacement CODr within 25 microns show little effect on concrete Chloridion permeability; the rate β of diffusion coefficient changes rises with the increase of the remaining displacement COD,