Experimental Investigations On Effects Of Mineral Admixtures On Electrical Receptivity Of Cement-based Materials

With the deep research of concrete,the electric conductivity attracts more and more attention as a basic physical properties,and the main research focus on the aspects of electrically conductive concrete,such as its electrothermal characteristics,temperature-sensitive properties and pressure-sensitive properties.However, the research of high-impedance concrete is relatively inadequate.In order to prevent the steel bar corrosion in structural concrete,the concrete should have higher specific resistance.Furthermore,stray current can accelerate the corrosion speed of the steel reinforcement in concrete and the embedded pipe near the subway track during the subway engineering,so improving the specific resistance becomes another effective solution besides the method of decreasing the stray current.And admixture,which acts as the sixth component in concrete,has some certain increasing effects in the impedance of cement due to its improvement in the chemical composition and microstructure of cement.Thus,the effects of different admixtures to the cement' specific resistance is analyzed based on empirically experiment.Zeolite powder,fly ash,silica fume and acid leaching residue of asbestos tailings are chosen as the admixtures to test its effects on the electric conductivity of cement paste and cement mortar through the changes in the volume,curing period,curing condition and water reducing agent.The results show that zeolite powder,fly ash,silica fume and acid leaching residue of asbestos tailings all have increasing effects in the impedance of cement,but the effects vary obviously due to different physical and chemical components and activities,and the order is:zeolite powder< fly ash< acid leaching residue of asbestos tailings