Review of the Microstructural Behavior of Geopolymer Cement Exposed to Acidic Environment Under CO2 Sequestration Conditions

Geopolymer cement is a promising alternative to wellbore cement for applications involving acidic environments, particularly in CO₂ sequestration wells. Its unique structure characterized by low Ca/Si ratio, low calcium content, and a highly cross-linked aluminosilicate gel matrix, provides superior resistance to chemical degradation, reduced permeability, and stable mechanical properties under high temperature and pressure conditions. The paper provides a review of the recent research done on geopolymer use for applications of CO2 sequestration, it compares the chemistry of the Portland-based cement with that of geopolymer, it deeply compares that chemistry and investigate its impact on the stability of the cementitious materials developed in both systems on the stability of each system in CO2 rich environment. It also discussed microstructural behavior of both geopolymer based cement and Portland-based cement in CO2 rich environment and compare the long-term stability of both systems in such harsh conditions. This review shows that Geopolymer cement matrix has a unique chemistry as characterized by low calcium content which make it more stable in harsh conditions compared to Portland-based cement. In terms of durability, geopolymer cement also showed long-term stability in acidic conditions. On the other hand, this geopolymer materials needs standardization and also there is no any reported field application of such geopolymer cement especially in acidic environments such as CO2 storage sites.