Performance evaluation of concrete surface treatment materials

Abstract

The reduction in the useful service-life of reinforced concrete structures in the Arabian Gulf is of concern to the construction industry. In this region, reinforced concrete structures rarely serve their full design life. In such environments, both concrete and reinforcing steel need to be protected. Among other alternatives, this protection can be achieved by the use of concrete surface treatment materials. While several studies have been conducted on the effectiveness of such coatings in inhibiting reinforcement corrosion, data are lacking on their performance in environments characterized by the presence of chloride and sulfate salts. Furthermore, the effect of thermal and moisture variations, typical of that prevailing in the Arabian Gulf environment, on the performance of concrete surface coatings are not fully elucidated.

In this study, the performance of six concrete surface treatment materials were evaluated. The results indicated that silane/siloxane with top coat was the most efficient in delaying the concrete deterioration in most of the exposure conditions. Among all the surface treatment materials used in the this study, silane/siloxane with top coat, silane and acrylic coating were the most effecive in providing adequate protection and hence reducing the rate of reinforcement corrosion. Furthermore, these three surface treatment materials were the most effective in reducing reinforcement corrosion in in-service structures. Also, silane/siloxane with top coat was most effective in reducing sulfate attack, as compared to other coatings. The concrete specimens treated with silane, silane/siloxane with top coat and acrylic coating exhibited the least water absorption and reduction in compressive strength as a result of thermal and moisture variations. Silane/siloxane with top coat and acrylic coating were effective in reducing carbonation of concrete.