دانلود رایگان مقاله به تعویق انداختن اثربخشی هگزیتول در هیدراتاسیون فاز سیلیکات سیمان

Abstract

This study focuses on the relationship between the retardation generated by hexitols (D-glucitol, D-galactitol and d-mannitol) on the hydration of the silicate phases of a white cement and on their interactions with the aluminate and sulfate phases. The impact of the aluminate and sulfate content of cement on their retarding effect was identified. The consumption of the stereoisomers as well as their effects on the ionic composition cement in suspension were studied and compared. The results showed that the aluminate and sulfate content of cement reduces the retarding effect of hexitols on the hydration of its silicate phases. Moreover, they adsorb differently on hydrating cement and complex with ions in solution. The impacts of the adsorption of these alditols on ettringite and of their complexation with aluminate ions in solution on their retarding effect on the hydration of the silicate phases of cement are discussed.

5. Conclusions

The retarding effect of hexitols on the hydration of the silicate phases present in cement was related to its C3A content. Their consumption during cement hydration and their impact on the ionic composition of cement suspensions were identified and compared. It was found that the C3A content of cement reduces the retardation generated by hexitols on the hydration of its silicate phases. These sugar alcohols are consumed during cement hydration and complexes form in solution. A relation was made between the adsorption of the polyols on ettringite and the reduction of their retarding effect on the hydration of the silicate phases of cement. Thus, the organic compounds adsorbed on ettringite would not be free any more to disturb the hydration of the silicate phases of cement and would induce a lower retardation. On top of that, a complexation of hexitols with aluminate ions in solution could contribute to the reduction of the retarding effect induced by these organics on the hydration of the silicate phases of cement.