Bond between Corroded Reinforcement and Concrete

Report, 2001

Corrosion of reinforcement leads to a volume increase; thus, splitting stresses are induced in the concrete. Thereby, the bond mechanism between the reinforcement and the concrete is influenced. In order to model the splitting stresses of the corrosion, the mechanical behaviour of the corrosive products needs to be known. Analyses of corrosion cracking tests led to the assumption that the corrosive products behave like a granular material; i.e. its stiffness increases with the stress level. This mechanical behaviour was, together with the volume of the rust relative to the uncorroded steel, given as input for a corrosion layer. This corrosion layer was combined with an earlier developed model of the bond mechanism, and implemented as a user-supplied subroutine in the finite element program DIANA. Finite element analyses of corrosion cracking tests and pull-out tests with corroded reinforcement were carried out. A reasonable good agreement between test results and analyses was obtained. The results show that this way of modelling can predict the decrease of bond when splitting of the concrete occurs, due to the combined action of corrosion and the bond mechanism.