This research examines the chemical activation of blast‐furnace slag pastes with alkaline solutions by means of various characterization techniques. Pastes were activated using sodium silicate solutions with modulus (Ms) of 0, 1, 1.5, 2, and Na 2 O at 5%, 10%, and 15%. Compressive strengths of up to 108 MPa were achieved for Ms = 1–1.5 after 720 d of curing at 20°C. The addition of Na 2 O > 10% resulted in the formation of hydrotalcite and carbonated pastes with low compressive strength. X ‐ray diffraction, microanalysis of outer products ( OP ), and nuclear magnetic resonance ( NMR ) results showed that the main reaction products in the activated cements with Ms = 1 and 5% Na 2 O had an average ratio Ca / Si = 0.71–0.9 and consisted of a mixture of two kinds of C–S–H; one similar to a 9 Å tobermorite‐type calcium silicate hydrate ( Ca 5 Si 6 O 16 ( OH ) 2 and other amorphous related to a cross‐linked structure of C–N–(A)–S–H gel. Both were intermixed with hydrotalcite and cross‐linked structures of silica gel.
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Burciaga-Díaz et al. (2013) studied this question.