Abstract: (8422 Views)
The article discusses the effect of calcined clays on the properties of Portland cement. An optimal method for calcining clays is proposed, which makes it possible to reduce the proportion of Portland cement clinker in cement to 60% and increase the strength characteristics from 55 MPa to 79 MPa. The study of the composition and structure of clays made it possible to select the optimal heat treatment parameters, at which the calcination products are characterized by the highest pozzolanic activity. It is shown that the use of alkali-activated calcined clays significantly increases the strength and durability of hardened cement binders compared to the composition without additives. In addition, calcined clays increase the frost resistance of cement in a 5% NaCl solution. The obtained experimental data are confirmed by thermodynamic calculations and the results of scanning electron microscopy.
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1. The NaOH solution allows to reduce the temperature of calcination of clays by 100-150℃
2. The pozzolan activity of thermally activated clays increases from 415 to 590 mg/g of the additive
3. Alkali-activated clays can significantly increase the strength of cement (by 1.5 times)
4. Cements with alkali-activated clays are able to resist freezing and thawing
Type of Study:
Research Paper |
Subject:
Ceramics