Sulphate and ASR Resistance of Concrete Made with Calcined Clay Blended Cements
This paper presents the results of several investigations concerning the durability of mortar and concrete with higher proportion of calcined clays in the cement part. For this purpose, different clays based on kaolinite, montmorillonite and illite were fired at optimum temperatures according to the strength contribution in cement. The raw materials were analyzed chemically (XRF) and mineralogically (XRD). The pore size distribution of the mortars was measured by mercury intrusion porosimetry. Cement pastes were produced in order to calculate the phase composition by XRD/Rietveld and to estimate the microstructure with SEM. The performance tests comprised investigations of the long-term behaviour in case of sulphate attack and alkali silica reaction respectively. The results show that the addition of the calcined clays are able to improve the concrete resistance against these exposures or at least doesn’t affect it negatively compared to the control. It can be followed that the application of cements with higher percentage of calcined clays substituting clinker is not restricted to only slightly loaded concrete constructions.
KeywordsPore Size Distribution Ordinary Portland Cement Cement Paste Composite Cement Pozzolanic Reaction
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