MODELING AND COMPARISON WITH MEASUREMENTS OF CHLORIDE ION TRANSPORT IN COASTAL CONCRETE TO PREDICT THE ONSET OF REINFORCEMENT CORROSION

摘要

The behavior of chloride ions introduced into concrete from concrete surface by marine environment and by use of marine aggregate was analysed for a coastal concrete structure. A mathematical model including the diffusion of chloride ion in aqueous phase of pores, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete and the chemical reactions of chloride ions with solid phase was presented. Finite element method was employed to carry out numerical analysis. Quantitative analysis was conducted to measure the distribution of the free chloride ion concentration in aqueous phase of concrete with potentiometric titration based on ASTM D 1820. The concentration profiles of chloride ions predicted by the mathematical model agreed favorably with the measured data. The results of this study may be used to predict the onset of reinforcement corrosion and to identify the maximum limit of chloride ions contained in concrete admixtures.