Model for cover cracking due to corrosion expansion and uniform stresses at infinity

The mechanical model of the cover layer cracking in reinforced concrete structures due to corrosion expansion of reinforcement and uniform stress at infinity is established in this paper. The principle of superposition and the series expansion technique of the theory of complex potential established by Muskhelishvili are applied. The complex stress potentials are assumed to be in the form of Taylor and Laurent series expansions, and the unknown coefficients are determined by the boundary conditions and the stress state at infinity. Finally the analytical solution for hoop stresses in concrete is derived. Referring to the previous studies in the literature, the equation for time of concrete cracking due to corrosion expansion of reinforcement and uniform stresses at infinity is established. It is found that the change of stress state at infinity may accelerate or decelerate the initiation of crack. In addition, compared with the case without corrosion, the existence of corrosion products can alter the location of cracking. Further analyses indicate that the effect of the ratio between reinforced bar and concrete on the cracking is insignificant, and that the possibility of cover layer cracking increases with increasing penetration of corrosion.