Effect of electrochemical treatment in mitigating OH^- leaching from cement paste and its microscopic analysis at BSE imaging.

Abstract

The present study concerns the electrochemical treatment between steel embedment and an external mesh in mitigating OH^- ion leaching from the cement paste into external water, which was ensured by a microscopic observation on the surface of the cement paste specimen at the backscattered electron (BSE) image analysis and by measuring the leaching rate for OH^- ions with time. The electrochemical properties for the treatment included 1000 mA/m² current density and 4 weeks duration. As a result, the pH at the electrochemical treatment in the external water accounted for 9.32 in the pH, while the untreated specimen indicated 13.46, implying a quite reduction of OH^- ion leaching to a water environment. The porosity on the surface was reduced to lower the access of external water, while the decomposition of C-S-H gel was lowered. Due to the precipitation of Ca(OH)₂, a further solidification of hydration phases could lower OH^- ion leaching.