Nonuniform Corrosion-Induced Stresses in Steel-Reinforced Concrete

Abstract

Understanding of cracking behavior of cover concrete is important for assessment of the remaining service life of corrosion-affected concrete structures. Predicting initiation of concrete cracking is commonly based on the evolution of stresses caused by the volume expansion of corrosion products on reinforcing bars. This paper presents an analytical method that is capable of providing the solution to two-dimensional (2D) elastic stress field caused by nonuniform volume expansion around the corroding reinforcing bars. The developed method features the formulation of a displacement model, which is applied as a boundary condition to simulate the effect of nonuniform corrosion on the deformation of the surrounding concrete. A closed-form solution to the stress field is obtained using the complex variable method of Muskhelishvili. Validation of the solution is supported by a comparison with finite-element-based simulation results. The solution reveals the evolution of stresses surrounding two typical locations of steel bars in reinforced-concrete components: the middle bar and the corner bar. Further, a comparison of stresses induced by nonuniform corrosion and uniform corrosion indicates that nonuniform corrosion pattern could lead to earlier initiation of crack given the same amount of corrosion weight loss.