The influence of few metals on the properties of tricalcium silicate

Numer wydania: 2018/3, strona 182
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In the paper the experimental results of the influence of ZnO, MgO, Al2O3, Cr2O3 and 2% MgO + 2%Al2O3 addition to C3S, the last one corresponding to synthetic alite, on the properties of these solid solutions are presented. The highest compressive strength had the paste of C3S + ZnO, after 28 days equal to 101 MPa. Significantly lower strength had the specimens with Al2O3 and the lowest the paste of C3S + 1% Cr2O3. On the second place after zinc was the paste of „synthetic” alite which had the high strength after 1 and 2 days and the same as the sample of C3S + 3% ZnO after 7 days. Good strength the specimens of C3S + 2% MgO are also assuring, with exception of the short period of curing. The microcalorimetry had shown the good correlation of the heat of hydration with strength, however, there was no correlation of the induction period time with early strength of the paste from C3S + ZnO. Simultaneously the observation of the pastes microstructure had shown that zinc is not uniformly distributed among the tricalcium silicate crystals; there are particles which do not contains zinc. The similar differentiation of C-S-H phase was observed; this phase containing zinc has the untypical morphology.