Theoretical approach for prediction of service life of RC pipe piles with original incomplete cracks in chloride-contaminated soils

Abstract

This paper presents an analytical approach to predict the service life of RC pipe pile exposed to chloride environment. The proposed approach properly considers the unique features of the RC pipe pile involved in the entire deterioration stage, including the chloride ion diffusion in both the inner and outer covers of the pipe pile, the effects of original incomplete micro-cracks on the diffusion, and the restriction effects of earth pressure on generation of transverse cracks due to corrosion expansion. The RC pipe pile is assumed to reach the end of its service life when corrosion-induced penetrating cracks appear in the concrete, and the deterioration process is divided into the diffusion stage and the corrosion stage to determine the service life of the RC pipe pile. The diffusion of the chloride ion in the concrete cover with incomplete micro-cracks is modeled by a compound radial diffusion model, and the corresponding diffusion solution is developed to determine the time that the reinforcement begins to rust. The time from corrosion initiation to penetrating crack initiation is determined by relating the rate of rust production to the deformation of the RC pipe pile. The proposed diffusion solution is validated by an ABAQUS numerical model and extensive parametric studies are conducted to investigate the impacts of the width and depth of the original incomplete micro-crack, cover thicknesses, diameter of the reinforcement bar, concrete strength, pile end types, as well as the embedded depth on the chloride concentration profile and service life of the RC pipe piles. The proposed method provides a novel, reliable and practical approach for evaluating the service life of RC pipe pile served in chloride environments, which is of great significance for durability design and maintenance of RC pipe piles.