Glass structure of industrial ground granulated blast furnace slags (GGBS) investigated by time-resolved Raman and NMR spectroscopies

Ground granulated blast furnace slags (GGBS) are glassy by-products from iron production that are commonly used as supplementary cementitious materials in blended cements. The glass structure of seven industrial GGBS was investigated by Raman and nuclear magnetic resonance spectroscopies. The complex composition of the slags induced multiple analytical challenges. Under usual continuous excitation, the Raman signal was masked by strong luminescence, so that analysis was carried out on a time-resolved Raman (TRR) device. TRR allowed to eliminate luminescence and resulted in exploitable spectra that showed variations in line with theoretical NBO/T values. The analysis of 27 Al and 29 Si NMR spectra was complicated by the presence of paramagnetic nuclei and the wide variety of environments. Nevertheless, 27 Al NMR showed that Al was present as a network former, mainly in fourfold coordination and careful analyses of 29 Si NMR spectra allowed the comparison of glass network polymerization of industrial GGBS in line with the theoretical NBO/T based on their composition.