Service Life Prediction of Reinforced Concrete Pipe Pile Due to Chloride Ion Corrosion

Abstract:

According to the chloride induced reinforcing steel corrosion mechanism, the service life of reinforced concrete (RC) pipe piles can be divided into two phases, i.e., the corrosion initiation phase and the crack propagation phase. Based on Fick’s second law and Faraday’s law, the governing equation of chloride diffusion into RC pipe pile was established and a chloride induced reinforcement corrosion model in RC pipe pile was developed. The corrosion initiation phase time and crack propagation phase time were predicted by determining the critical chloride concentration and the critical attack penetration depth, respectively. Then the effect of surface chloride ion concentration, diffusion coefficient, cover thickness, reinforcement diameter, volume expansive ratio and the ratio of tensile strength to elastic modulus on service life of RC pipe piles was further analyzed, respectively. The analysis results indicate that the service life of RC pipe pile decreases with the increasing of surface chloride ion concentration, diffusion coefficient, reinforcement diameter and volume expansive ratio, while the service life of RC pipe pile increases with the increasing of cover thickness and the ratio of tensile strength to elastic modulus.

Key words:reinforced concrete pipe pile; chloride diffusion; reinforcement corrosion; crack propagation; service life