Hydration of Cement in Hydrothermal Conditions

2 Hydration of Cement in Hydrothermal Conditions 4.2.1 Phases in the CaOSiOj-H.O System 

In Fig. 4.53 the stability ranges of some of calcium silicate hydrates as a function of temperature and pressure are presented [156]. Because of experimerrtal difficulties the Ca0-Si02-H20 system has not been elaborated and the Uqttid phase remaining in equilibrium with the solid phases is not knowa However, the research was undertaken to learn the stable, equilibrium phases, formed at variable C/S molar ratio, as a function of temperature and pressure these problems was studied by Roy [162]. She investigated also the cirrves of saturated water vapom of many calcium silicate hydrates [163]. 

In hydrothermal conditions the solnbility of silica rapidly increases while the solnbility of calcinm hydroxide decreases (Figs. 4.54 and 4.55) [164]. This is undoubtedly the reason of quick reaction of silica with calcium hydroxide or with calcium silicates in these conditions and formation of calcium silicates hydrates. In Table 4.4 the classification of the calcium silicate hydrates according to Taylor [21] is shown the reference works are also given [9, 63, 154, 155, 161, 165-181]. 

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Phase Composition of Cement Hydrated in Hydrothermal Conditions... 

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