Investigation on the Distribution Characteristics of Partial Carbonation Zone of Concrete

Abstract

This paper aims to investigate the distribution characteristics of the partial carbonation zone of concrete. A series of experimental carbonation tests considering the effect of external temperature, concentration of CO2, and relative humidity were implemented. The pH values of the simulated pore solution of the powder sample of concrete are presented. The carbonation model based on the mass-transfer theory is proposed. The results indicate that the pH value of the simulated pore solution can be applied to demarcate the complete and partial carbonation zones of carbonated concrete. The numerical model can be used to preferably simulate the distribution of complete and partial carbonation zones. The length of the partial carbonation zone increases with the increase of temperature and decreases with the increase of relative humidity. The lengths of the partial carbonation zone generally increase with the increase of concentration of CO2. Concrete with a high initial diffusion coefficient is conducive to the diffusion of carbon dioxide. The length of the complete and partial carbonation zones can be sensitively affected by the activation energy.