Three-dimensional corrosion propagation in steel rebars of RC columns with early-age cracks

Abstract

• Research developed a numerical framework incorporating finite element analysis (FEA) and random processes to simulate chloride-induced corrosion and rust formation in reinforcing steel embedded in RC members having early-age cracks. • The multiphysics phenomena of corrosion initiation and propagation are modelled through adequate considerations of chloride diffusion through cracked concrete, heat and moisture transport, polarization of steel rebars, and rust formation. • FEA of a RC column with randomly distributed vertical, horizontal and inclined early-age cracks shows lower corrosion initiation times of steel rebars in the vicinity of cracks and time-evolution of corrosion pit along the length and periphery of rebars. • Research outcome signifies the strong influences of early-age cracks in induction and propagation of pitting corrosion in RC members. This paper presents numerical simulation of chloride-induced corrosion and rust formation on steel rebars embedded in RC members with early-age surface cracks. A finite element analysis (FEA) framework, which integrates physiochemical and electrochemical processes of rebar corrosion with random generation of early-age cracks, is adopted to predict temporal progression of corrosion pit along the length and periphery of rebars. The multiphysics phenomena of corrosion initiation and propagation are modelled through adequate considerations of chloride diffusion through cracked concrete, heat and moisture transport, polarization of steel rebars, and rust formation. FEA of a RC column with randomly distributed vertical, horizontal and inclined early-age cracks shows lower depassivation times (i.e., corrosion initiation times) of steel rebars in the vicinity of cracks. This results in higher reduction of rebar diameter at crack zones in comparison with that observed at distant locations from cracks where uniform corrosion of rebars prevails. Based on the observed trajectories of time-evolving rust formation along the length of rebars, for different crack patterns, an average pitting length of 140 mm is observed. Research outcome signifies the strong influences of early-age cracks in induction and propagation of pitting corrosion in RC members.