Pozzolanic Activity of Calcined Clays


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Title: Pozzolanic Activity of Calcined Clays

Author(s): Simone E. Schulze and Jorg Rickert

Publication: Special Publication

Volume: 289


Appears on pages(s): 1-11

Keywords: clay, natural calcined pozzolana, reactive silicon dioxide, supplementary cementitious material, X-Ray Fluorescence (XRF), Differ¬ential Thermal Analysis (DTA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM)

Date: 9/14/2012

In this research project several natural clays were examined in detail by X-Ray Fluorescence (XRF), Differential Thermal Analysis (DTA) and X-Ray Diffraction (XRD) to define optimal burning conditions to meet the requirements regarding the reactive silicon dioxide content of pozzolanic materials acc. to EN 197-1. The calcined samples were examined by means of Scanning Electron Microscopy (SEM), XRD and concerning their pozzolanic activity. Cements were made using the calcined clay with the highest reactivity as main constituents besides Portland cement clinker, respectively, and the cement performance according to EN 196 was examined. In summary, calcined clay may qualify as main constituent in cement. Its pozzolanic activity depends on the chemical and mineralogical composition of the starting material as well as the conditions of thermal treatment.