Simulation of chloride transport in concrete with stress induced damage

Durability of reinforced concrete structures in Arabian Gulf region is a major problem which results from corrosion of the reinforcement occurring as a consequence of chloride transport in concrete. Although chloride-induced corrosion is directly influenced by the chloride diffusivity property of the concrete, the diffusivity itself is affected by a number of other factors like mix parameters, stress level leading to damage, moisture content, chloride binding capacity and ambient temperature. There is a need to simulate the chloride transport in concrete with regard to the coupled impact of stress level leading to damage, binding capacity and the effect of crack widths which reflects the actual mechanism of chloride transport in concrete structures.;This research presents experimental and numerical results using COMSOL multiphysics finite element model used to simulate the chloride transport in damaged concrete samples. The electrochemical transport of chloride in concrete was evaluated using NT BULD 492 test for chloride migration in concrete subjected to different levels of compressive-induced damage. Besides, eight reinforced concrete beams of 1200 mm span were subjected to 40%, 60% 75% and 90 % of its ultimate flexural strength and loaded back to back using steel frames and subjected to 8% of NaCl solution for three months to simulate the coupled problem of chloride diffusion and mechanical loads leads to induced damage.;It was found that there is a significant increase in the chloride diffusivity with the increase of tensile stress in the RC beams subjected to flexural loading and a good correlation was established between effective chloride diffusion coefficient and the level of the damage in RC beams. A crack influencing function Fw was developed to correlate the crack width (w) and the ratio of chloride diffusion coefficient in the crack Dcr to the chloride diffusion coefficients in sound concrete Do and two configuration were used in the RC beams which matches consistently the chloride diffusion: the first one when the diffusion relates as a function of distributed damage and second one when it is govern by the crack width. Finite Element model using COMSOL was matching well the experimental results of the mechanical behavior as well as the transport of the chloride in damaged RC beams.