Investigation of Chloride Penetration and Steel Corrosion in Repaired Concrete after Exposure to Marine Environment of Thailand

Abstract

This paper aims to investigate the chloride penetration and the steel corrosion in the repaired concrete specimen after exposure to the marine environment of Thailand. The repaired concrete specimen was made in the laboratory and then exposed to the tidal zone of the marine site. There were two parts in the repaired concrete specimen, which were original concrete (OC) and replaced concrete (RC). Cement-only concrete and fly-ash concrete with water to binder ratio (w/b) of 0.65 were used for making the OC, while the RC was produced from fly-ash concrete with w/b of 0.55. The binder replacement by fly ash was employed at 30% and 50%. From the experimental results, it was found that types of concrete in the OC and RC significantly affected the chloride penetration and steel corrosion in the repaired concrete specimen. Chloride penetration resistance of the repaired concrete specimen that the RC made from fly-ash concrete with 50% of FA was higher than that from fly-ash concrete with 30% of FA, while the steel corrosion level was also lower.  In addition, the availability of the initial chloride in the OC influenced the chloride penetration profile and steel corrosion level in the RC.