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原文传递 Development of Calcined Clays as Pozzolanic Additions in Portland Cement Concrete Mixtures.

题名：	Development of Calcined Clays as Pozzolanic Additions in Portland Cement Concrete Mixtures.
作者：	Zayed, A.; Sedaghat, A.; Shanahan, N.; Stetsko, Y.; Lorentz, B.
关键词：	Portland cement, Mortar compressive strength, Florida (state), Calcined clay, Kaolinite, X-ray fluorescence, X-ray diffraction, Thermogravimetric analysis, Requirements, Chemical oxides
摘要：	A number of clay sources in the state of Florida were characterized in this study. It was determined that field material contains a substantial portion of sand, approximately 65-80%, which needs to be beneficially processed before the material can be used as a pozzolan. The clay fraction met the chemical oxide composition requirements of ASTM C618. All samples had a sum of SiO2, Al2O3, and Fe2O3 oxides above 70%, and their SO3 content was below 4%. Additionally, the clay fraction had a high kaolinite content, 70-90%, which indicates a good potential of producing a high-quality pozzolanic material on calcination. It was determined that complete dehydroxylation of all the clay samples occurred at 600 degrees C and that further heating to 800 degrees C did not increase the amorphous content of the calcined clays. Pozzolanic activity of the material calcined at 600 degrees C was evaluated by compressive strength testing at 7 and 28 days at a replacement level of 10%. The results showed that the Florida clays obtained can be calcined for use in portland cement concrete materials, and are capable of yielding strength indices meeting the requirements of ASTM C618 at a 10% replacement level, and are, therefore, suitable for use in concrete as Class N natural pozzolans.
报告类型：	科技报告