Research of the Influence of Pyrogenic Nanosilica on the Heat Hydration and Cement Stone Microstructure

The article presents the results of studies to determine the kinetics of heat generation, which makes it possible to judge the rate of binder hydration during cement hydration without additives and with the addition of superplasticizer and nanodispersed silicon dioxide – nanosilica. The kinetics of heat release during hydration of cement was determined by an indirect method to change the hydration temperature of the system via the logger Testo-176T4 temperature. With the introduction of superplasticizer, the hydration of cement slows down due to the adsorption of the additive on the surface of the cement grain, which prevents the access of the liquid phase. This leads to a drop in the temperature of the hydrated binder in the post-induction period of hydration. With the introduction of nanosilica in optimal amounts, the induction period of hydration is reduced due to the interaction of nanosilica with cement hydration products. It is shown that the combined use of superplasticizer and nanodispersed silicon dioxide accelerates cement hydration due to the dispersion of cement grain in the presence of superplasticizer and the interaction of nanosilica with portlandite with the formation of an additional amount of calcium hydrosilicates. The data of electron microscopy analysis are presented, which prove the change in the microstructure of cement stone with the addition of additives, which leads to an improvement in the physicomechanical characteristics of hydrated stone not only in the early but also in the later stages of hardening.

L.A. URKHANOVA, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it. );
S.A. LKHASARANOV, Candidate of Sciences (Engineering), (This email address is being protected from spambots. You need JavaScript enabled to view it. ),
E.V. BADMAEVА, Eengineer (This email address is being protected from spambots. You need JavaScript enabled to view it.)

East Siberia State University of Technology and Management (40V, Klyuchevskaya Street, Ulan-Ude, Republic of Buryatia, 670013, Russian Federation)

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