Comprehensive study of fly ash binder developed with fly ash – alpha gypsum plaster – Portland cement

In this study, a new type of fly ash binder has been developed using fly ash, hydrated lime sludge and Portland cement, as well as α-gypsum plaster as stimulator. The hydration process and microstructure of the fly ash binder was investigated with differential thermal analysis, X-ray diffraction and scanning electron microscopy. These studies showed that the strength development of binder takes place through formation of ettringite and tobermorite. The durability of fly ash binder was assessed by its performance in water by immersion and by alternate wetting and drying cycles at 27–50 °C. The results reveal absence of leaching of the matrix in fly ash binder as well as reduction in strength and enhancement in weight loss with the increase in temperature and cycles. The fly ash binder is found suitable for use in masonry mortars, concrete and bricks.