碳化程度对混凝土中氯离子扩散系数的影响

Experimental Study on Effect of Concrete Carbonization Degrees on Chloride Diffusion Coefficient

为研究碳化程度对混凝土中氯离子扩散系数的影响,通过室内混凝土快速碳化试验获得不同碳化程度的混凝土试块,再结合氯离子快速渗透试验,计算各混凝土试块的氯离子扩散系数.试验结果表明:完全碳化试件与部分碳化试件的氯离子扩散系数未见明显差别;而完全未碳化试件的氯离子扩散系数最大,与已碳化试件有明显差距.混凝土的碳化会降低氯离子的扩散系数;碳化使混凝土的孔隙率降低、密实度提高,一定程度上阻止了氯离子向混凝土内部扩散,完全碳化试件的氯离子扩散系数约为未碳化试件的1/2左右.利用pH计对部分碳化试件进行了测试,结果表明方法可行.

Different carbonized concrete specimens were obtained by rapid carbonization test and their chloride diffusion coefficients were tested and calculated by rapid permeability test.The results show that there’s no obvious difference between chloride diffusion coefficient of totally carbonized concrete and that of partly carbonized concrete while that of non-carbonized concrete is higher than the former two.It can be concluded that there exits substantial benefits of reducing the chloride diffusion coefficient by concrete’s carbonizing; concrete’s carbonizing increases concrete’s density to some extent by reducing the porosity. The chloride diffusion coefficient of totally carbonized specimen is about 1/2 that of non-carbonized specimen. This paper also introduces a method by using pH device to measure the pH of different carbonization degree concretes and offeres the changes of the pH.