Investigating the effect of rebar corrosion order and arrangement on cracking behaviour of RC panels using 3D discrete analysis

Abstract

In real structures, corrosion cracking patterns tend to be complex as a result of congested rebar arrangements and non-uniform corrosion distribution. It is challenging to understand the internal corrosion cracking behaviour based only on the limited amount of visible surface cracks. The present study attempts to use a meso-scale discrete element method, the three-dimensional rigid body spring model (3D-RBSM), to simulate factors that affect corrosion cracking. Factors considered in reinforced concrete panels with multiple corroded rebar includes, corroded rebar location, corrosion order among rebars and rebar arrangement. Three different cases are simulated and the results are compared with previously published experimental results. In one set of simulations, the non-uniform rebar corrosion profiles obtained in the experiments are utilized, with the results showing similar cracking patterns to the experimental ones. In a second set of simulations, uniform corrosion is assumed so as to conduct a parametric study of the same specimens for an accurate understanding of each influencing factor. It is observed that when all rebars corrode simultaneously, the initial cracks propagate along the outer rebars because this is where the confinement effect is minimum. Cracking along inner rebars is delayed due to strong compression zone resulting from mechanical interaction among corroded rebar stresses. However, this compression zone is reduced when the rebars corrode in two stages and cracking occurs at all the rebar locations. Cracks that initially form along the inner rebars can close up when corrosion of the outer rebars occurs later.