Numerical simulation of neutralization of concrete exposed to CO2 and SO2 at different temperature and relative humidity

A neutralization model of concrete eroded by CO2 and SO2 was established, and the effects of different erosion time, ambient relative humidity and ambient temperature on neutralization process were investigated. The dissolution process of solid-phase calcium in concrete and the expansion damage caused by erosion products were introduced into the model. The changes in neutralization degree, gas diffusion coefficient, porosity, CaCO3 content and CaSO4 content of concrete after erosion were analyzed. The predicted results indicate that with the increased of erosion time, the depth of carbonated area exceeded that of sulfated area by far, since the SO2 erosion reaction was concentrated at the concrete surface. When the ambient relative humidity was 50 %, the depth of the completely sulfated area was the largest. When the ambient relative humidity increased, the depth of partially sulfated area decreased. With the increased of ambient temperature, the existence range of CO2 increased significantly, while the existence range of SO2 gradually decreased. © 2024