氯离子在开裂混凝土中的扩散特性研究

Diffusion Property of Chloride in Cracked Concrete

考虑荷载裂缝宽度与裂缝深度的相关性,基于AgNO_3显色法研究了混凝土裂缝的存在对氯离子扩散范围的影响.通过钻孔取粉测定了混凝土中的氯离子含量,研究了裂缝特征的单一因素对氯离子的扩散特性影响.结果表明:裂缝的存在加速了氯离子在混凝土中的扩散过程;氯离子的扩散系数随着裂缝宽度的增加而增大;裂缝深度的变化对氯离子的扩散深度有一定影响.基于试验结果建立了裂缝宽度(裂缝深度)与氯离子扩散系数之间的指数函数关系式.

AgNO3 colorimetric method was introduced to study the effect of cracks on diffusion of chloride in concrete,taking the relationship between the load crack width and crack depth into account.Through drilling powders,the chloride content in concrete was measured and the influence of crack width or crack depth on the chloride diffusion process was studied.The results indicate that cracks accelerate the diffusion of chloride in concrete.The chloride diffusion coefficient increases with the increase of crack width.The crack depth also has certain influence on the chloride diffusion process.Based on test results,an exponential relation between the crack width(crack depth)and the chloride diffusion coefficient is established.