Siamak Riyazi - M.Sc. student of structural engineering, School of Civil Engineering, University of Tehran, Tehran, Iran Construction Materials Institute, School of Civil Engineering, University of Tehran, Tehran, Iran
Ali Dousti - Construction Materials Institute, School of Civil Engineering, University of Tehran, Tehran, Iran
Mohammad Shekarchi - Construction Materials Institute, School of Civil Engineering, University of Tehran, Tehran, Iran

Harsh marine exposure conditions provide an aggressive condition for reinforced concrete structures, mainly due to its hot, humid and saline environment. In this study,variations in diffusion coefficient value over time is investigated and compared in five different exposure conditions for silica fume concrete with different water to binder ratiosunder long-term exposure in a marine environment. Samples were taken at the ages of 3,9 and 36 months and analyzed to determine the chloride diffusion coefficient and surfacechloride content. Regression analysis of the surface chloride content data is carried out byapplying two empirical models that were in the literature and compared to each other to suggest the best fitted model in order to make a logical trend about surface chloride content for long term exposure conditions.

diffusion coefficient, exposure condition, silica fume, surface chloride