摘要: |
Chloride ions are known to promote the corrosion of steel in reinforced concrete. This project was undertaken to investigate the efficacy of washing, to reduce existing chloride content and chloride ion uptake. The project consisted of a laboratory component over four years and a field component over two years. In the field component test sections of a coastal bridge were pressure washed on a once per year and twice per year schedule. The laboratory effort consisted of washing trials conducted on concrete blocks exposed to salt water to determine whether chloride ions can be removed from the concrete and whether the ingress of chloride ions can be reduced. Field testing was discontinued after two years because the laboratory results indicated that the washing frequencies used on the bridge were much too low to produce any change in chloride levels. After four years, the laboratory trials showed that daily washing with fresh water can appreciably reduce the ingress of chloride ions, but occasional washing is ineffective. Washing does not appear to significantly reduce existing chloride concentrations in the bulk concrete. |