Influence of ground perlite on the hydration and strength development of calcium aluminate cement mortars

Calcium aluminate cement (CAC) concretes are desirable owing to their rapid strength development and resistance high temperatures, sulfates acids. They suffer two drawbacks, however, cost loss due conversion of water-rich hydration products more stable structures, resulting in a drop strength. Although its rate is dependent on temperature moisture, the process thermodynamically inevitable but can be prevented by adding sufficient quantities supplementary cementing materials (SCMs) form an alternate, hydrate, Stratlingite (C2ASH8). Based this premise, natural pozzolans could mitigate conversion, also reducing cost. This study investigated influence, hydration, replacing 25–75% CAC with ground perlite (GP), inexpensive abundant pozzolan. Paste mortar mixtures water-to-binder ratios 0.40 0.60 were cured air at 23 °C or water 40 °C. The influence Na2SO4 promote formation was investigated. A multi-method approach comprising X-ray diffraction (XRD), isothermal calorimetry, thermal analysis, compressive used. confirmed many containing GP. Wet-cured mortars ?50% GP 1% contained showed continuous increases up 90 d. Rapid-, slow-progressing drops observed air-cured wet-cured < 50% Mortars 75% did not experience ultimate strengths much lower than even converted pure mortar. Heats pastes decreased linearly replacement despite setting times being shortened.