Hydration of tricalcium silicate in paste — Kinetics of calcium ions dissolution in the aqueous phase

Studies on early stage hydration of tricalcium silicate incorporating silica nanoparticles: Part I

“…According to nucleation theory of CH, the nucleation of CH is rate determining parameter and induction period occurs because CH is not precipitated, even after the saturation of the solution due to the poisoning of the nuclei by silicate ions. The induction period ends when the level of super-saturation is sufficient to overcome this effect [15][16][17]. In nucleation theory of C-S-H, the rate of reaction during the induction period is controlled by nucleation and growth of the initially formed C-S-H and the induction period ends when growth of C-S-H begins [19].…”

The Developing Microstructure in Portland Cement

“…Although dissolved silicates are never found in any substantial quantity, small amounts have been measured [80,82,83] during the first minutes which then subsequently decreases with time, Fig. 8.…”

“…Several studies [80][81][82][83][84][85][86][87] have been carried out on relatively dilute systems and although data during the first minutes is difficult to obtain, the concentration of Ca ++ appears to rise more rapidly in less dilute systems [81,82], at higher temperature [82], and with increasing reactivity [83], Degree of agitation and particle size influence the solubility of lime [88] and these trends might also be observed for C 3 S. Similarly, the concentration of 0H~ ions rapidly increases during the early stages [85]. The pH rises to a value of about 12.5 [84,89] within minutes and remains constant for hours.…”

“…8, as does hydroxyl ions, and usually [80][81][82][84][85][86][87], but not always [83], a state of supersaturation is reached with respect to Ca(0H)2 before the end of the induction period. A state of supersaturation is always [80][81][82][83][84][85][86][87] eventually attained.…”

Kinetics of dissolution-precipitation reaction at the surface of small particles: modelling and application

“…It is a well-established fact that C 3 S hydration proceeds via the dissolution of tricalcium silicate and the precipitation of the CaO x -SiO 2 -H 2 O (i.e. CSH) phase [16]. The formation of CSH has been shown to occur by heterogeneous nucleation and growth, which depend upon the lime concentration.…”