CONCRETE

[:ru]Кун Сянмин[:en]Kong Xiangming[:] [:ru]д-р техн. наук, проф., Университет Цинхуа, Факультет гражданского строительства, Пекин, Китай[:en]Dr. Eng. Sc., Prof., Department of Civil Engineering, Tsinghua University, Beijing, China[:]

[:ru]Лу Цзычэнь[:en]Lu Zichen[:] [:ru]канд. техн. наук, Университет Цинхуа, Факультет гражданского строительства, Пекин, Китай[:en]Ph.D. candidate, Department of Civil Engineering, Tsinghua University, Beijing, China[:]

Alitinform №1 (46) 2017 г. 46-54 p.

Abstract

An overview of interaction of different types of polymer colloids with Portland cement is provided, including the ethylene/vinyl acetate (EVA) polymers, styrene butadiene rubber (SBR) and styrene-acrylate copolymer (SA). Generally, all of these polymer colloids would retard the cement hydration and influence the hydration products., The working mechanism of SA polymer colloids with Portland cement is mainly discussed in this paper based on our previous research work. It is found that both the complexation of carboxyl group contained in the polymer with calcium ions and/or adsorption of the polymer particles on the surface of cement particles are the main causes for the retardation effect of polymer latexes on the cement hydration. In addition, instead of the main polymer composition in the core of polymer particles, the surface functionalization of polymer particles (the charge type and charge density) are decisive factors responsible for the described retardation effect. In-situ X-ray diffraction (XRD) results clearly show that polymer colloids with different surface property have similar effects on the silicate reaction in cement hydration but highly different effect on the aluminate reaction.

Key words:

cement hydration, polymer colloid, adsorption, retardation, complexation