For the first stop (0.5 J/g) of the Na2Si1.7O4.4-activated slag paste (Figure ) and the first two stops (0.5 J/g and 23 J/g) of the Na2CO3-activated one (Figure ), only a broad resonance was visible with a maximum at approximately -90 ppm to -93 ppm. This contribution, partially hidden by the unreacted slag in the one-pulse 29 Si NMR spectra, corresponds to a diversity of Q3 and Q4 environments with some of the Si tetrahedra linked to Al . and 165 J/g) and in the last spectrum of the Na2CO3-activated paste (108 J/g). The Q2 resonance, which appeared at around -84 ppm in the 29 Si NMR spectra, could be separated into two different contributions at -83.9 ppm and -85.8 ppm. They were attributed to bridging Q2 b and pairing Q2 p tetrahedra, respectively .