International Journal of Sustainable Building Technology and Urban Development ISSN:2093-761X(Print) 2093-7628(Online)

The hydration reaction in its true nature is very complex and this study aims to understand hydration of OPC-43 grade (IS 8112-1969) using powder X-Ray diffraction. The Powdered X-Ray diffraction is an effective tool used in this paper to quantify the crystalline phases present in cement and the changes in these crystalline phases at different age of hydration starting from initial-set, final-set, 1 day, 3 days, 7 days, 14 days, 28 days and 56 days of curing. The research work presents the procedure involved in making the cement slurry, sample preparation for powder x-ray diffraction, identification of cement minerals such as alite, belite, aluminate and ferrite and their modification to CSH, CH, AFm and AFt phases. Minor phases present in cement are also quantified. The results indicate that the cement has high lime saturation factor, alumina ratio and silica ratio. The magnesia content in the cement is about half of the maximum value and the SO3 content in the cement exceeded the value stipulated in IS 8112-1969. The maximum change in hydration products was obtained during the initial setting period after that the change became steady. The total hydrated products formed, increases with age up to 7 days. After 7 days, there was a decline in the hydrated products up to 21st day due to the decrease in Afm phase and decrease in CSH phase content. The rate of consumption of cement minerals and rate of formation of hydration products followed the same pattern with age. The maximum rise in compressive strength of cement mortar was observed during the period between 1 day to 3 days of curing. The increase in strength of cement is concurrent with increase in hydration product in the same time interval. The outcome of this study will help to understand the processes associated with strength gain, soundness and durability of OPC-43 utilised to various constructions and aid in decision making process related with fresh and hardened concrete.