A review on corrosion of cement-based materials in CO2-rich karst groundwater

In karst areas, groundwater has high concentrations of carbon dioxide. It causes decalcification of cement-based materials by reacting with calcium hydroxide and calcium silicate hydrate. Therefore, the corrosion by CO2-rich groundwater has become a significant concern as it may reduce the service life of concrete structure. Based on the chemical reactions, the corrosion can be divided into leaching corrosion, carbonic acid corrosion, and acid corrosion. Calcium carbonate formation and dissolution are critical steps in corrosion process. The loss of calcium from cement results in cracking and spalling of the cement-based materials. The environmental and material factors had a significant effect on the corrosion rate. Based on the study in simulated karst water, adding supplementary cementitious materials or low-calcium alkali-activated materials can improve the corrosion resistance of the cementitious materials.