Mechanism of Polymer-Cement Co-matrix Formation

It is believed that a cx)-matrix phase which consists of cement gel and polymer films is generally formed as a binder according to a three-step simplified mcxlel shown in Fig. Grosskurth proposed a similar 

Mixtures of cement gel and unhydrated cement partides enveloped with a close-packed layer of polymer particles 

Cement hydrates enveloped with polymer films or memberanes 

The process of the polymer film formation on the cement hydrates is represented in Fig. 2.3.P1 

First Step. When polymer latexes are mixed with fresh cement mortar or concrete, the polymer partides are uniformly dispersed in the cement paste phase. In this polymer-cement paste, flie cement gel is gradually formed by the cement hydration and the water phase is saturated with calcium hydroxide formed during the hydration, whereas the polymer partides dqrosit partially on the surfaces of the cement-gel-unhydrated-cement partide mixtures. It is likely that the calcium hydroxide in the water phase reacts witit a silica surface of the aggre tes to form a calcium silicate layer.I It is confirmed that tire formation of the calcium hydroxide and ettringite in the contad zone between tire cement hydrates and aggregates is attributed to the bond between them.I lPl 

It is believed that a co-matrix phase which consists of cement gel and polymer films is generally formed as a binder according to a three-step simplified model shown in Fig. 2.2.Grosskurth proposed a similar model indicating the formation of the polymer-cement co-matrix.I l Sugita, et al.l l have recently investigated the microstructures and composite mechanism of latex-modified pastes and mortars, and found the interfacial layer of 

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Latex modification of cement mortar and concrete is governed by both cement hydration and polymer film formation processes in dteir binder phase. The cement hydration process generally precedes the polymer formation process. ] In due course, a co-matrix plW is formed by both cement hydration and polymer film formation processes. It is important to understand the mechanism of the co-matrix ph formation. 

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