Microstructural features and technical properties of calcium sulfoaluminate-based cements

A rapid-hardening and dimensionally stable calcium sulfoaluminate (CSA) cement (i), consisting of 80% CSA clinker and 20% anhydrite by mass, and an expansive CSA-based binder (ii), composed by 44% CSA clinker, 16% anhydrite and 40% high-strength and rapid-hardening CEM I 52.5 R Portland cement (used also as a reference term), were cured with a 0.5 water/solid mass ratio from 4 hours to 56 days and submitted to microstructural (differential thermal-thermogravimetric and X-ray diffraction analyses, mercury intrusion porosimetry, scanning electron microscopy) and physical/mechanical (workability, shrinkage, compressive strength) tests. DTA-TG and XRD analyses assessed the role played by the main reactions occurring in the hydrating systems. The porosimetric and morphological features well correlated with the expansive/non-expansive behavior of the investigated cements