Finite element analysis of the effects of radial expansion of corroded reinforcement

A finite element (FE) model of the effects of corroding reinforcement on the surrounding concrete was validated against the results of simulated corrosion tests in which internal pressure was applied to holes cast in concrete. The model was then used to explore the effects of bar radial expansion, due to the formation of corrosion products, on the cracking of cover concrete. The predictions were compared with test results from reinforced concrete accelerated corrosion specimens. The aim of the analytical investigation was to reveal the mechanism for the development of concrete cracking due to the corrosion of reinforcement. The three-dimensional physical specimens were idealised as two-dimensional analytical models under a plane strain assumption. Corrosion of reinforcement was modelled as either an internal pressure or a radial expansion to analyse the results of simulated and accelerated corrosion specimens, respectively. The FE analytical results indicate that the radial expansion of corroded reinforcement causes concrete cover to crack in four different stages: internal cracking, external cracking, penetration cracking and ultimate-cracking. It was also found that the FE analytical results could be used to explain qualitatively the experimentally determined relationship between amount of corrosion for concrete cracking and ratio of concrete cover to bar diameter, as well as that between reinforcement bond strength and amount of corrosion.