Effect of Stone Dust Content in Manufactured Sand on Chloride Diffusion Coefficient of Various Strength Grade Concretes
The influence of stone dust content on chloride diffusion coefficient in C30, C40 and C50 grade concretes were investigated by means of the natural immersion test, XRD test, MIP test, SEM and TGA test, respectively. The experimental results showed that the chloride diffusion coefficient in C30 grade concretes decreased with increasing the stone dust content, but it decreased first and then increased with increasing the stone dust content in C40 and C50 grade concretes. The hydration degree for cementitious and compressive strength for concrete was slightly promoted by using stone dust replacing cementitious at a low level. For C30 grade concretes, the porosity decreased with increasing the stone dust content in fine aggregate, but for C40 and C50 grade concretes, the total porosity decreased first then increased with increasing the stone dust content. And the concrete pore structure was the main factor that influences the changes of chloride diffusion coefficient in concrete.