The factors defining the efficiency of earthed shields made of electroconductive cementing compositions for the electrocorrosion protection

Abstract

The factors that define the efficiency of earthed coating shields made of the Portland cement-based electroconductive cementing composition were experimentally studied to provide the electrocorrosion protection. It was established that the current intensity is increased by the three orders of magnitude as the current flows through the water-saturated earthed coating shield made of the Portland cement-based electroconductive composition. This fact confirms the feasibility of the use of such shields to drain the leakage currents that are considerably increased achieving unsafe values especially in wet weather. It was also established that protective shield properties depend on the ratio of the contact area of the coating-shielded steel earth electrode to the area of entire coating shield. As this ratio is increased the intensity of the current flowing through the structure reinforcement and concrete is decreased and the intensity of current flowing through the earthed coating shield is increased. It confirms the efficiency of the use of earthed coating shields made of the Portland cement-based electroconductive compositions to provide the electrocorrosion protection caused by leakage currents, for example for such structures as railway d. c. current-electrified passenger platforms.