Mixtures made from materials containing reactive oxides of calcium, aluminium, Sulphur and silicon which are able, upon hydration, to generate calcium trisulphoaluminate and silicate hydrates, have been studied with a view to possible applications in the field of preformed building elements. The materials employed were natural gypsum, phosphogypsum, fly ash, blast furnace slag, Portland cement and hydrated lime. The samples were cured at 55, 70 and 85-degrees-C and 100% RH for 24 h, followed by further curing at ordinary temperatures and humidities (21-degrees-C, 67% RH) for up to 28 days. The cured samples were tested for compressive strength and shrinkage. It has been found that the most important effect on the strength is due to the pre-curing temperature, while the post-curing time has much less effect. In general, the optimum pre-curing temperature is 70-degrees-C. Satisfactory strength results were obtained even with systems containing up to 80% waste materials.