Abstract
In this paper, the physicochemical properties and hydration mechanism of cement-free binders developed from fluorogypsum has been discussed. The results showed maximum attainment of strength (38 MPa), low water absorption (<5%) and porosity (<10) with anhydrous calcium chloride and sodium sulphate activators. The enhancement in strength with hydration period was due to the conversion of fluorogypsum into gypsum through formation of intermediate unstable salt. The reaction products were characterised using X-ray diffraction and scanning electron microscopy (SEM) techniques. SEM studies showed the appearance of prismatic and needle-shaped crystals of variable sizes interspersed with anhydrate fluorogypsum plaster which make matrix dense and compact. This change in morphology of anhydrite plaster is responsible for enhancement in strength, reduction in water absorption and porosity of cement-free binders. The engineering properties of the construction materials for use in plastering, masonry works, concrete, blocks and tiles developed from this binder are reported.
Acknowledgements
The work reported in this paper forms a part of the normal research programme at the CSIR Central Building Research Institute, Roorkee (India). The authors express their sincere thanks to Prof. S.K. Bhattacharyya, Director, Central Building Research Institute, Roorkee for his support, encouragement and permission to publish the paper.
Disclosure statement
No potential conflict of interest was reported by the authors.