Title:
Effect of Hardening Conditions on the Structure of Cement
Author(s):
Ekaterina Potapova, Sergey Sivkov, and Ivan Korchunov
Publication:
Symposium Paper
Volume:
326
Issue:
Appears on pages(s):
82.1-82.10
Keywords:
cement structure, chlorides in cement, colorimetric method, corrosion, frost-resistance, plasticizing agent
DOI:
10.14359/51711065
Date:
8/10/2018
Abstract:
The introducing of different plasticizing agent makes it possible to increase the strength and reduce the porosity of cement and concrete, besides, it promotes higher frost resistance. The effect of admixtures depends on cement mineral composition.
The research shows that the freezing-thawing destruction of cement occurs both due to physical causes and changes in the crystalline hydrates in the set cement. According to the modern methods of physical and chemical analysis it was established, that the transformation of monosulfate (3CaO·Al2O3·CaSO4·12H2O) to ettringite and backward in the freezing-thawing conditions occurs in cement by the formation of intermediate compounds - Friedel`s salts. The hydrated phases volume changes in the system leads to the internal appearance of stresses and its gradual destruction.
The results obtained in this work allow recommending plasticizers admixtures, which reduce water resistance and porosity that leads to increasing the frost resistance of cement and concrete. This is confirmed by the results of the colorimetric analytical method.