Evolution of advanced geopolymeric cementitious material via a novel process

A novel process for making advanced geopolymeric cementitious materials has been developed and patented in India and the USA. The novel process was conceptualised using the principles of solid-state chemistry. The process involves mechano-chemical reactions between fly ash and sodium hydroxide in the dry state. The dry solid powder thus obtained can then be used for the preparation of advanced geopolymeric material by just the addition of water. The process overcomes some of the drawbacks of the conventional manufacture of geopolymeric materials, and especially obviates the need to handle highly alkaline solution and the requirement of sodium silicate as this is synthesised in situ in the developed process. The advanced geopolymeric material thus produced was characterised using x-ray diffraction analysis, infrared spectral studies and scanning electron microscopy. It was found that even the dry powder material contained all the necessary mineral phases found in conventional geopolymeric materials. The developed advanced geopolymeric material was tested for mechanical strength as per the relevant Indian standard and was found to possess compressive strength 28·5% higher than that of conventional geopolymeric materials.