Effects of temperature, relative humidity and carbon dioxide concentration on concrete carbonation

The influences of temperature, relative humidity (RH) and carbon dioxide (CO 2 ) concentration on concrete carbonation in a simulated environment were investigated. The carbonation depth, compressive strength and surface strain of concrete under different simulated environments were tested. The results showed that the effects of temperature, RH and carbon dioxide concentration on carbonation depth and compressive strength were significant. There was a linear relation between temperature and carbonation depth as well as compressive strength of concrete. A power function existed between carbon dioxide concentration and carbonation depth, and there was an exponential function between carbon dioxide concentration and compressive strength. The carbonation of concrete was more significant when the RH was within the range 60­–80%. Significant differences of phase composition and hydration products were observed before and after the carbonation, mainly manifested as attenuation and disappearance of diffraction peaks of hydration products.