Use of micro-reactors to obtain new insights into the factors influencing tricalcium silicate dissolution

Molecular and submolecular scale effects of comb‐copolymers on tri‐calcium silicate reactivity: Toward molecular design

“…The delay of silicate hydration at too low sulfate content results from a higher concentration of aluminate ions in solution. [45][46][47][48] In contrast, with a sufficient amount of calcium sulfate, most aluminate ions are consumed by ettringite precipitation, whereas additional sulfate ions inhibit tricalcium aluminate dissolution, allowing the silicate to hydrate normally (Figure 2). 27 At c*, all the surface of precipitated ettringite is occupied by all the added polymer, leaving the silicate still largely free of polymer (zone II).…”

“…At c**, BET specific surfaces are found to be high and roughly identical ( Figure S7), most probably due to the onset of the formation of calcium aluminate hydrates (noted AFm) typical of undersulfated systems. These phases are known to strongly adsorb and/or intercalate comb-copolymers [49][50][51] and should therefore be able to adsorb all PCEs, leaving silicates to only be retarded by aluminate ions 45,46,48,52 (insert IV, Figure 5). This explains first why a similar retardation as polymer free undersulfated systems is observed and second why the retardation does not depend on polymer dosage as it does not change much over a large range of carboxylates concentration.…”

Advances in dissolution understanding and their implications for cement hydration

“…In parallel, it was observed that protonation of silicate monomers and free oxygen atoms strongly stabilize alite surface and reduce its solubility [30,50]. As mentioned earlier, the surface bonding of ions [33,51] or the adsorption of polymers [42] also stabilize the alite surface and in turn extend the dormant period. Although mechanisms have not been resolved, the analogy with the hydration of annealed alite suggests a site specific interaction [42], without any impact on the subsequent acceleration rate (Figure 4b): adsorbed ions and molecules passivate the surface and block the dissolution of line defects, like dislocations outcropping at the surface, or point defects.…”

: A force field database for cementitious materials including validations, applications and opportunities

“…Earlier it was found that a pH sensitive retardation of C 3 S hydration by aluminate ions occurs through the formation of Si−O−Al covalent at the outermost surface of C 3 S, but that the amount of the hydrates formed increases at a later stage. [57,188] Our molecular dynamics simulations help to establish that aluminates can adsorb on (Fig. 7 a).…”