A critical review of magnesium silicate hydrate (M-S-H) phases for binder applications

What makes cements bind?—A proposal for a universal factor

“…MSH has an amorphous (nanocrystalline) layered silicate structure with tetrahedral layers as in phyllosilicate minerals. 6,23 Therefore, MSH is considered to be a complex composite-like phase consisting of multiple amorphous hydrate magnesium silicate phases 24 whereas its crystalline counterparts can be Mg-silicate minerals such as sepiolite and lizardite 7 with no binding capacity. As for magnesium carbonate cement, the hydrous carbonate-containing brucite (HCB) is a defective ( i.e.…”

Exploring the Potential of Nonclassical Crystallization Pathways to Advance Cementitious Materials

“…In conclusion, while MS cements show promise not only in specific applications such as hazardous waste encapsulation, refractory castables, and clay stabilization but also in the production of structural and nonstructural building components due to their reported high strength development, they still face limitations such as slow ambient setting and high-water demand, which hinder their wider use . Despite these challenges, extensive research efforts dedicated to MS cements over the past decade have significantly improved our understanding of the material and proposed potential solutions to some of these hindrances . This progress indicates that with ongoing research, investment, and exploration, MS cements could have practical applications in current construction practices.…”

“…For a more complete understanding of magnesium silicate cements, covering aspects not discussed here, such as mechanical properties, durability, thermodynamic modeling, and M−S−H phase stability aspects, we recommend the excellent review by Sreenivasan et al published in April 2024. 357 MS is produced in most studies by using MgO and microsilica as precursors and admixtures that reduce the highwater demand of Mg-based binders, as already discussed. The slow setting at ambient temperature, which prevents practical onsite and large-scale applications of magnesium silicate binders, has been attributed to the slow dissolution of brucite in the presence of M−S−H.…”

“…358 On the basis of the existing literature, the formation of M− S−H using MgO and microsilica solids mixed in the presence of solids can be described through the following stages: (i) dissolution of MgO, (ii) formation of brucite, (iii) dissolution of brucite in the presence of silicate species, (iv) formation of a transient M−S−H phase (lower degree of ordering), (v) transformation into the final M−S−H with a high degree of ordering (Figure 46). 357 With respect to the nucleation of M−S−H from magnesium and silicate species in solution, the first fundamental steps have been taken to understand the pathway of M−S−H formation in synthetic systems. 195 Our research revealed a unique multistep pathway in which a complex mixture of defined hydrated magnesium-(sodium)-silicate oligomers exist in the solution before nucleation, similarly to the C−S−H system.…”

Investigation of Crystallization Growth Characteristics of Mg(OH)2 Crystals under Unconstrained Conditions

“…The synthesis of magnesium hydroxide Mg(OH) 2 primarily utilizes magnesium salts, bischofite, and active magnesium oxide, among other raw materials [17][18][19]. Jiang et al employed magnesium chloride hexahydrate and sodium hydroxide as starting materials, utilizing urea and ethanol to tailor the morphology of Mg(OH) 2 .…”