Presented by: Luciano de Andrade Gobbo
Pozzolan are a broad class of siliceous or siliceous and aluminous materials which, in themselves posses little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. The quantification of the capacity of a pozzolan to react with calcium hydroxide and water is given by measuring its pozzolanic activity. Amorphous (glassy) fractions have an important role in the pozzolanic activity.
The aim of this work is to present results and steps on the analysis of glass content of some pozzolanic materials. Some fly ash and natural pozzolan were used on the quantification perfomed with X-ray diffraction using the external standard method together with the Rietveld method and an external intensity standard is used to put all Rietveld quantities onto an absolute scale. The standard determines the instrument intensity constant, the so called K-factor and can be any 100% crystalline material consisting of one or of several phases. In this study the external standards were Rutile (TiO2), Corundum (Al2O3) and also Zincite (ZnO). The fly ash samples were mainly composed by mullite, quartz, hematite and glass and the natural pozzolan of aluminosilicate glass and also quartz, feldspar and some clay mineral.
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Panelist:
Luciano de Andrade Gobbo - XRD Building Materials & Minerals Specialist
Luciano de Andrade Gobbo was born in São Paulo State, Brazil, in 1975. He started his studies of Geosciences at the University of São Paulo, Brazil in 1994. In 1999 he started his X-ray diffraction studies in the University of Milan, Italy, and in 2002 he finalized his studies with a Master’s dissertation on Clinker quantification by XRD-Rietveld method. From 2001-2004 he worked as applied mineralogist in Brazilian cement industry using optical microscopy and XRD. In 2004 he started his PhD research on Brazilian cement quantification by Rietveld method at the University of São Paulo; in the same year he joined Panalytical Brazil, São Paulo, as application specialist for X-ray diffraction for Latin America, based in São Paulo, Brazil. In 2009 he finished his PhD and in 2014 he became XRD Building Materials & Minerals specialist for all the Americas, his currently position. In the end of 2016 he moved to the headquarter of Malvern Panalytical for the Americas in Westborough-MA, working on building materials, mining and also as the benchtop XRD application specialist.