Stoichiometry of Slag Hydration With Calcium Hydroxide

Published

April 1, 2002

Author(s)

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

Abstract

The stoichiometry of the reaction between ground granulated blast furnace slag (GGBFS) having an empirical formula of C_7.d88^ S_7.39 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.

Citation

Journal of the American Ceramic Society

Volume

85

Issue

No. 4

Pub Type

Journals

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Keywords

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

Citation

Richardson, J. , Biernacki, J. , Stutzman, P. and Bentz, D. (2002), Stoichiometry of Slag Hydration With Calcium Hydroxide, Journal of the American Ceramic Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860290 (Accessed April 25, 2024)