Abdul Nabi Lashari2022-05-182022-05-184978https://drepo.sdl.edu.sa/handle/20.500.14154/692The useful service-life of reinforced concrete structures in aggressive environments is less than that in normal conditions. In such environments, both concrete and reinforcing steel need to be protected. Among many alternatives, this protection can be achieved through the use of corrosion inhibitors and surface coatings. While several studies have been conducted on the effectiveness of such inhibitors in mitigating reinforcement corrosion, data are lacking on their performance in environments characterized by the concomitant presence of chloride and sulfate salts. Further, the effect of heat-cool cycling, typical of that prevailing in the Arabian Gulf, on the performance of concrete surface coatings is not fully elucidated. In this study, four corrosion inhibitors and four concrete surface coatings were evaluated. The results indicated that calcium nitrite was efficient in delaying the initiation of reinforcement corrosion in the concrete specimens contaminated with cloride, chloride plus sulfate and those made with sea water. In the concrete specimens made with brackish water or unwashed aggregates, all the inhibitors were generally effective in reducing the rate of reinforcement corrosion. However, the type of inhibitor and its dosage was observed to be dependent on the type of contamination. Similarly, the depth of carbonation in the mortar specimens incorporating corrosion inhibitors was less than that in the control specimens. The combined effect of delayed reinforcement corrosion, decreased carbonation and lower wate of reinforcement corrosion extended the useful service life of reinforced concrete structures. Among all the surface coatings used in this study, acrylic and siloxane coatings were the most effective in reducing the rate of reinforcement corrosion. The concrete specimens treated with these two coatings exhibited the least water absorption.enThesis