Electrochemical treatment to mitigate the alkali leaching from concrete to an aquatic environment

摘要

In this study, the electrochemical treatment was used to block the leaching of alkali ions from concrete body, which would otherwise enhance the alkalinity of an aquatic environment and thus lead to a devastating contamination. The current density applied to the surface of concrete ranged 250, 500, 1000 mA/m~2, and the duration of treatment was 1, 2, 4 weeks respectively. As a result, it was found that the treatment was effective in lowering the alkali leaching to an aquatic environment: an increase in the current density and duration of treatment resulted in a dramatic reduction of pH in the solution on the concrete surface. Its pH was reduced up to 8.33, whilst untreated concrete had a value of 12.91 in the pH. Simultaneously it is notable that the duration of treatment is a key shot to sustain the leachate blocking on the concrete surface. At the lower current density (250 mA/m~2), the pH of the solution was eventually increased about 100 days after the completion of the treatment, while the pH at the highest current (1000 mA/m~2) was mostly kept with no further increase.