Influence of water-to-binder ratios on the performance of limestone calcined clay cement-based paste for mining applications

This study aims to investigate the impact of various water-to-binder (w/b) ratios by mass (0.3–2.0) on the performance of limestone calcined clay cement (LC 3 ) pastes. The flowability, setting time, density, unconfined compressive strength, hydration, and microstructure of LC 3 pastes under different w/b ratios were thoroughly investigated. The results show that increasing the w/b ratio extends the flowability and setting time while significantly reducing the unconfined compressive strength of LC 3 pastes. LC 3 pastes with w/b ratios above 0.6 exhibited a final flow diameter surpassing 167 mm, indicating good flowability. The 28-d unconfined compressive strength decreased from 82.3 to 1.3 MPa as the w/b ratio increased from 0.3 to 2.0. This study confirmed that the relationship between unconfined compressive strength and the w/b ratio of LC 3 follows Abram’s law. Furthermore, a modified gel/space ratio was proposed to reflect the concentration of solid products, effectively explaining the influence of the w/b ratio on strength, with an R 2 of 0.96.