Cracking of the concrete cover due to reinforcement corrosion: A two-dimensional lattice model study

Corrosion of steel reinforcement is a serious problem for durability and serviceability of reinforced concrete. As the reinforcing steel corrodes, it expands and exerts pressure on the surrounding concrete cover, causing tensile stresses in concrete. This ultimately leads to cracking and spalling of the concrete cover, further exacerbating the durability problems of a structure and increasing the rate of its deterioration. In order to study cracking mechanisms due to reinforcement corrosion, mechanics of the problem was implemented in a two-dimensional lattice model. Heterogeneous nature of concrete was taken into account in the mechanical analysis. Firstly, the case of uniform corrosion was tested, and successfully verified using experimental data from the literature. Also, it was found that cracking pressure is not a deterministic value, and depends on local mechanical parameters. Secondly, two pitting scenarios were tested and compared to the uniform corrosion case. Pitting results in significant reduction of cracking pressure, compared to the uniform corrosion case. Based on the proposed model, some conclusions with implications for engineering practice were drawn.