Hydration and strength development of low-clinker (<50 %) factor limestone calcined clay cements (LC3): A comparative study with natural pozzolans

This study investigates the hydration kinetics and strength development of low-clinker (50–35–25 %) limestone calcined clay cements (LC3) in comparison with Portland pozzolanic cements (PPC) incorporating natural pozzolans (NP). Using a combination of experimental analysis and thermodynamic modeling, the study examines phase assemblage evolution, sulfate requirements, and strength/porosity development. Results indicate that LC3 cements exhibit enhanced hydration kinetics, increased precipitation of carboaluminates, and superior porosity reduction compared to PPC, owing to the higher reactivity and alumina content of calcined clays. This leads to a phase assemblage that yields a higher volume of solids at comparable degrees of reaction. The improved phase development enables additional clinker savings of 40–46 % while maintaining strength performance within PPC standard requirements. These findings highlight LC3 as a viable low-carbon alternative, particularly in markets where PPC is commonly used, offering significant CO₂ reduction potential while ensuring adequate mechanical performance.