Characterization of magnesium silicate hydrate (M-S-H)

International audienceIn this study, the structure of synthetic magnesium silicate hydrated phases (M-S-H) and the distribution of wateras a function of the Mg/Si ratio were investigated. Different analytical techniques indicated that M-S-H phasesare nano-crystallite hydrated phyllosilicates with relatively short coherence length (1.2 nm) and small particlesize (> 200m2/g). Zeta potential and cations exchange capacity measurements showed a negative surfacecharge on M-S-H from the deprotonation of the silanol groups. The negative surface charge is compensated byexchangeable magnesium or others cations. Combined analyses were used to characterize the water distributionin M-S-H revealing the following: i) confined water; its amount depends mainly on the relative humidity ii) veryconfined water (or possibly water coordinated to magnesium), and iii) hydroxyl groups bound to magnesium andto silicon