Numerical investigations on the influence of ITZ and its width on the carbonation depth of concrete with stress damage

The effect of the interfacial transition zone (ITZ) on carbonation of stress damaged concrete is investigated by a joint simulation using ABAQUS and COMSOL. Two FEM software use identical mesh and respectively determine the stress damage and carbonation depth. The parameters utilised in the simulation are obtained by a uniaxial test of mortar cylinders and a 450-day carbonation test of cubic concrete. The influence of ITZ and its width (20-100 mu m) on carbonation are studied. For undamaged concrete, ITZ reduces the aggregate-phile effect by 10%. For stress damaged concrete, uneven carbonation fronts are observed, and ITZ increases the maximum carbonation depth by 7-11 and 6.8 times within 1000 days under compression and tension, respectively. An increasing ITZ width also spreads the concentrated damage and promotes the carbonation depth. Comparing the result of ITZ = 100 mu m to that of 20 mu m, the maximum carbonation depth is doubled, and the average carbonation depth is increased by 37%.

Automated summary

The effect of the interfacial transition zone (ITZ) on carbonation of stress damaged concrete was investigated through a joint simulation. The results showed that the ITZ reduced the aggregate-phile effect in undamaged concrete, while in stress damaged concrete, it led to uneven carbonation fronts and increased the maximum carbonation depth.