Properties of Cement Mortar and Concrete

Steel in cement mortar is in the passive state represented by field II in Fig. 2-2. In this state reinforcing steel can act as a foreign cathodic object whose intensity depends on aeration (see Section 4.3). The passivity can be lost by introduction of sufficient chloride ions or by reaction of the mortar with COj-forming carbonates, resulting in a considerable lowering of the pH. The coordinates then lie in field I. The concentration of OH ions can be raised by strong cathodic polarization and the potential lowered, resulting in possible corrosion in field IV (see Section 2.4). 

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The properties of cement mortar and concrete are closely related to the cement hydration. Polymers have good effect on the mechanical properties and durability of cement mortar and concrete. This improvement is probably come from the effect of polymer on the microstructures and the cement hydration. In this case, some reports about the effect of polymer on cement hydration are found in the references [1-3]. The authors have carried out some research on the influence of polymer dispersion and powder on cement hydration [4-7]. This paper will show some of the results focusing on the effect of SBR dispersion and powder on cement hydration, including the heat evolution, the calcium aluminate hydrates and the calcium silicate hydrates. 

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