Influence of Comb-Polymer Structure on C<sub>3</sub>S Phase Hydration
- 1 Chemistry, Materials and Chemical Engineering Department, Politecnico di Milano, Milan, Italy
- 2 Innovation Department, ITALCEMENTI, Stezzano (BG), Italy
- 3 R&D Department, CTG Italcementi Group, Stezzano (BG), Italy
- 4 Chemistry, Materials and Chemical Engineering Department, Politecnico di Milano, Milan, Italy
- 5 Chemistry, Materials and Chemical Engineering Department, Politecnico di Milano, Milan, Italy
Abstract
The cement hydration delay is due to comb-polymers (PCP), used as dispersant agent during the preparation of the ce ment paste. In order to evaluate the role of the PCP structure on hydration, the comb-polymer is separated in two main parts: the backbone (PAA) and the dispersing chain. A linear polymer made up of PEO, M w = 1000, with a carboxylic head suitable to link the inorganic surface, was synthesized to simulate the effect of the dispersing-side chain. The hy dration delay of C-S-H formation induced by comb-polymer on CEM I and C 3 S phase was analyzed by conduction calorimetry and the morphology of the crystalline structure in growth by SEM, specially studying the relation between structure and hydration time. The results show that the hydration delay is mainly ascribable to the comb-shaped struc ture as a whole, where PEO chain, as from considerations on energy, might assume conformations able to modify the salt concentration near the cement surface. The different hydration rates are tentatively related to the crystal growth and the surface texture observed by SEM.
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