The Effect of Different Exposure Conditions on the Chloride Diffusion into Concrete in the Persian Gulf Region

Concrete structures are increasingly being deteriorated in Persian Gulf region, mainly due to the chloride-induced corrosion of the embedded steel. Severity of this environment in which the average temperature exceeds more than 30oC and the relative humidity is about 70-90 % has made Persian Gulf one of the most aggressive environments in the world. Nevertheless, there has not been any specific work to develop a model for the service life design in this area. In this study, necessary experiments were conducted to evaluate various exposure conditions influencing the diffusion of chloride ion into concrete. Thus, 15x15x60 cm concrete prism specimens were fabricated with different silica fume contents and water/binder ratios. After 28 days of curing in saturated calcium hydroxide solution, the specimens were subjected to different exposure conditions in Persian Gulf region for three months. Soil, atmosphere, Submerged, tidal and splash zones were five major exposure conditions investigated in this study. Accordingly, the powder samples for chloride analysis were ground off specimens at the age of 3 month during exposing period, and subsequently their chloride contents at different depths from exposed surface were determined according to ASTM C114. The diffusion coefficients (Dc) an