0000000000801848
AUTHOR
A. Nonat
showing 3 related works from this author
Study of "alite-tricalcium silicate-gypsum"complex system
2007
International audience; The systematic study of “alite-C3A-gypsum” systems by using simultaneously the dynamic mode rheometry and the isothermal microcalorimetry made it possible to specify interactions between the different components and to quantify the effect of the mixtures on the cohesive properties of C-S-H. In the system “alite-C3A”, the presence of aluminate ions decreases both the growth rate of C-S-H and the ratio dG' /dQ which represents the increase in the elastic modulus dG' corresponding to the formation of a certain quantity of C-S-H, estimated by released heat dQ; for the great quantities of C3A, there is a positive effect of the surface developed by calcium hydroaluminates …
Retardation mechanisms of sodium gluconate for hydration of pure tricalcium silicate and alite in cement
2009
Sodium gluconate is known to be a strong set retarder of cement. Many studies have been devoted to the interactions between cement and gluconate at early ages but the true mechanisms of this retardation is not yet elucidated. The most important phase in cement is alite which is a tricalcium silicate containing impurities. Tricalcium silicate hydration leads to the nucleation and growth of calcium silicate hydrates which are responsible for setting and hardening of cement paste. This work is devoted to the influence of sodium gluconate on the early hydration, period during which calcium silicate hydrates should nucleate and begin to grow on anhydrous grains. Previous studies have shown that …
Effect of the hydration temperature on mechanical resistance of Portland cement mortar and paste.
2007
The hydration of white cement and tricalcium silicate has been investigated at three temperatures (5, 25 and 45°C). Samples were tested after eight periods of hydration during which samples were immersed in saturated lime solution, using: compressive strength determination, and thermogravimetry. Increasing temperature initially accelerated the hydration but a lower hydration degree was observed in the long term comparatively to lower temperatures. The same kind of effect was observed for the evolution of the compressive strength. Whatever the hydration temperature, it was found that compressive strength is a linear function of the hydration degree of which the characteristic is the same for…