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Stoichiometry of Slag Hydration With Calcium Hydroxide



J M. Richardson, Joseph J. Biernacki, Paul E. Stutzman, Dale P. Bentz


The stoichiometry of the reaction between ground granulated blast furnace slag (GGBFS) having an empirical formula of C7.d88^ S7.39 and calcium hydroxide (CH) was investigated. Scanning electron microscopy (SEM) was used to determine the slag consumption as well as the Ca/Si ratio in calcium silicate hydrate gel (C-S-H) products. A tentative stoichiometric ratio of 2.6 mol of CH consumed per mole of slag reacted was determined using two methods. By combining consumption data determined separately for slag and CH a molar stoichiometry of 2.79 was found. Similarly, by directly determining the Ca/Si ratio in the C-S-H gel product, a range for the molar stoichiometry between 1.65 and 3.42 was found. Finally, a comparison of the stoichiometry of the slag/CH reaction was made with slag/portland cement hydration. The basic features of both appear similar. In the C-S-H gel around slag grains, a calcium-to-silica ratio of 1.3 to 1.4 was found for both slag/CH and slag/cement systems.
Journal of the American Ceramic Society
No. 4


calcium hydroxide, calcium silicate hydrate, cement, kinetics, reaction, slag


Richardson, J. , Biernacki, J. , Stutzman, P. and Bentz, D. (2002), Stoichiometry of Slag Hydration With Calcium Hydroxide, Journal of the American Ceramic Society, [online], (Accessed June 24, 2024)


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Created March 31, 2002, Updated October 12, 2021