Influence of freezing-induced damage on the carbonation rate of concrete

The paper considers two deterioration mechanisms of concrete, frost-induced damage and carbonation. The objective of experimental study is to investigate how the microstructure degradation of cement-based materials caused by the cyclic water freezing affects the carbonation rate. Influence of water to cement ratio and addition of air-entraining admixture was analysed. The change of cement mortar pore structure due to frost damage was investigated by multi-cycle mercury intrusion porosimetry and capillary absorption test. The carbonation depth was examined using phenolphthalein indication and pH microelectrodes. The experimental results indicate that the ice-induced damage noticeably enhances the carbonation of concrete. Addition of AEA reduces considerably changes of the pore size distribution caused by the frost damage.