The parameters used in these two equations are the relative intensity of the unreacted slag 𝐼 slag rel obtained from the NMR spectral fits (Tables SI and SII of the Supplementary Materials), the formulation mass ratio between the activator and the slag ). To estimate r(t), it was assumed that the hydration was completed at 309 h for all the cements when using Qmax 1 , and only for the NaOH-activated pastes when using Qmax 2 . The NMR spectra actually show that there was still a significant amount (more than 60%) of unreacted slag in the cements at that time. This is coherent with what has been observed by other researchers with 50 % of reacted slag at 180 days .