Calcium sulfoaluminate (CSA) blended cements

Fly ash from municipal solid waste incineration (MSWI) was successfully used as a main raw material in sintering and preparing a calcium sulfoaluminate (CSA) cement clinker in the laboratory. In order to maximise the utilisation of solid waste, the focus in this study was on the suitability as supplementary cementing materials (SCMs) of MSWI fly ash, limestone powder (LI), fly ash and slag powder (SL). Compared with the hardened cement containing different types and amounts of SCMs, samples containing 20% combined admixtures had significantly improved compressive strengths, especially the sample containing 5% LI + 15% SL. In addition, the durability of the CSA blended cement-based materials was studied. When 20% combined admixtures were added, the resistance to shrinkage, carbonation and sulfate attack were improved, while the addition of combined admixtures had a negative effect on the resistance to water permeability. The results of this study contribute to the understanding of how to develop a sustainable cement industry through the maximum utilisation of solid waste.