Finally, the case of Na2CO3-activated slags (Figure ) was similar to the one of the Na2Si1.7O4.4-activated pastes. Indeed, the first two spectra, at 0.5 and 23 J/g, only showed the formation of a N-A-S-H gel with incorporated tetrahedral Al, giving rise to a resonance at 62.2 ppm. The spectrum of the most hydrated sample, at 108 J/g, also presented the same four resonances as with Na2Si1.7O4.4, namely a tetrahedral contribution at 67.7 ppm, a pentahedral contribution at 36.2 ppm, and octahedral ones at 9.9 ppm and 5.3 ppm.