Development of fly ash based geopolymeric cementitious materials for new millennium

The present studies have been carried out with a view to exploit the potential of fly ash from thermal power, Sarni (Madhya Pradesh), India as resource material for making geopolymeric cementitious materials. Sample cubes of 5 cm x 5 cm x 5 cm dimensions of green cementitious material were prepared in the laboratory by alkali activation of fly ash by varying quantity of alkali and sodium metasilicate. Prepared cubes were dried at room temperature and cured at 90 degrees C in hot air oven for 48 h. Compressive strength of cubes was determined and characterisation of the prepared geopolymeric cementitious materials of three different mix compositions has been done using sophisticated techniques namely X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Compressive strength is found in the. range of 13 to 22 N/mm(2) for three different mix compositions. Highest compressive strength is observed for Mix 3 and is comparable with 7 days compressive strength of Portland cement which is 22 N/mm(2) as per IS 269, ordinary Portland cement; 33 grade-specification. The prepared geopolymeric cement free cementitious material will be useful for making cement free concrete for non structural applications.