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°C in nitrogen atmosphere, at the heating rate of 10 °C min −1 , the sample mass was 9–13 mg, measurements were carried out after 3, 7, 14 and 150 days of cement hydration
], and adiabatic calorimeters [ 12 ] present the commonly used devices. The effects of silica fume [ 13 ], finely ground limestone [ 14 ], fly ash [ 15 ], blast furnace slag [ 16 ], or wastes from fluidized bed combustion [ 17 ] on cement hydration are
A120), ettringite (all samples), hillebrandite (B28, B120 and C28) and xonotlite (B28, B120 and C28). The existence of relicts (belite and plagioclase) is caused by an unfinished process of cement hydration, due to the insufficiency of
which in turn are resulted from the thermal stresses [ 11 , 12 ]. The heat released by the cement hydration and the hydration rate are commonly regulated by adding mixed materials or transferring additive such as fly ash and fluorgypsum [ 13 – 15
, which adversely affect the quality of concrete by accelerating the rate of moisture loss and also the rate of cement hydration causes self-desiccation in concrete [ 6, 7 ]; furthermore, leading to increase cracking tendency of concrete especially at
permeability [ 1 – 4 ]. These properties are developed through pozzolanic reaction between amorphous silica in the SCMs and Portlandite, (Ca(OH) 2 ), released during cement hydration and formation of insoluble calcium silicate hydrates (C–S–H) [ 5
during the early stages of cement hydration—evaluation by thermal analysis . J Therm Anal Calorim . 2007 ; 87 : 3 715 – 720 . 10.1007/s10973-006-7772-2 . 13. Cherem da Cunha , AL
V . Influence of aluminic pozzolans, quartz and gypsum additions on portland cement hydration . In: Proceedings of 12th international congress on the chemistry of cement, W2-05.2, Montreal, Canada. 8-13 July 2007
Cu can lower the rate of hydration of cement pastes including C 3 A by forming some protective layers on the unhydrated cement minerals [ 16 – 18 ]. The retardation of cement hydration is also dependent on the solubilities of the protective layer
Artificial pozzolanic cement pastes containing burnt clay with and without silica fume
Physicochemical, microstructural and thermal characteristics
effect of cement hydration (which generates CH) and the pozzolanic reaction (which consumes CH). The results of Fig. 2a indicate that the free lime contents obtained for all admixed OPC–BC pastes are lower than these of the neat OPC paste. As hydration
