The stability of supersulphated cement (SSC) is investigated. The hydration products of cement pastes prepared at a water
cement ratio of 0.27 were determined by thermogravimetry (TG) and X-ray diffraction (XRD). Ettringite, one of the initial
hydration products, is shown to be stable under conditions of storage at 25, 50 and 75°C and when subject to relative humidities
of 100, 53 and 11% of water vapour in each case. The effect of drying on ettringite stability at the higher temperatures is
discussed in relation to the relative humidity.