Natural Zeolites: Pathways to Green and Durable Cement and Concrete

Rocks containing natural zeolites have been used since antiquity as components of concrete and mortars. As pozzolans, natural zeolites react with slaked lime (Ca(OH)₂) or Portland cement and water to form sparingly soluble calcium silicate and calcium aluminate hydrates. This pozzolanic reaction improves the long-term strength and durability of the mortar and concrete. Moreover, natural zeolites may replace Portland cement, reducing CO₂ emissions from cement production, thereby making them an interesting decarbonization solution. Ongoing mineralogical investigations have revealed the influence of zeolitic framework topology, Si/Al ratio, and cation-exchange capacity on the pozzolanic reactivity of natural zeolites within cementitious matrices. This research paves the way to better utilization of this natural resource and leveraging its CO₂-saving potential in construction.