低水胶比混凝土电阻率的影响因素探究

An Investigation of the Factors Affecting the Electrical Resistivity of Concrete under Low Water-to-Cement Ratio

通过掺入硅灰和矿粉,研究了掺合料对低水胶比混凝土电阻率的影响;同时探究了水泥种类、纤维种类和养护制度对混凝土电阻率的影响。研究表明:掺合料通过固化导电离子、优化孔隙结构,能有效提高低水胶比混凝土的电阻率,掺入5%硅灰能制备出90 d电阻率为5941 Ω∙m的高强高阻抗混凝土;低水胶比混凝土的电阻率对水泥的组分很敏感,相较于硅酸盐水泥使用硫铝酸盐水泥能提高3倍的混凝土电阻率;纤维对混凝土电阻率的影响和纤维自身导电性相关,加入导电性强的钢纤维,会显著降低低水胶比混凝土的电阻率;随着养护环境湿度的增加低水胶比混凝土的电阻率呈下降趋势,使用硫铝酸盐水泥制备的混凝土,水养状态和自然养护状态的电阻率最大差异为16倍。

The influence of admixtures on the electrical resistivity of low water cement ratio concrete was studied by adding silica fume and slag. The effect of cement type, fibre and curing condition was also explored on the resistivity of concrete. The research shows that the admixture can effectively improve the electrical resistivity of low water-to-cement ratio concrete by curing conductive ions and optimizing the pore structure. High-strength, high-impedance concrete with a 90 d resistivity of 5941 Ω∙m can be prepared by mixing 5% silica fume in cement. The electrical resistivity of low water-to-cement ratio concrete is sensitive to the composition of the cement, and the use of sulphoaluminate cements increases the electrical resistivity by a factor of three compared to Portland cement. The effect of fibers on concrete resistivity is related to the fiber’s inherent electrical conductivity. The addition of highly conductive steel fibers significantly reduces the electrical resistivity of low water-to-cement ratio concrete. The electrical resistivity of low water-to-cement ratio concrete tended to decrease with increasing humidity of the curing environment, and the maximum difference in electrical resistivity between the water-cured state and the natural cured state was 16 times for concrete prepared using sulphoaluminate cement.