CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
BLENDED CEMENTS WITH KAOLINITIC CALCINED CLAYS: STUDY OF THE IMMOBILIZATION OF Cr(VI)
Autor/es:
MÓNICA TREZZA, ALEJANDRA TIRONI, EDGARDO F. IRASSAR, ALBERTO N. SCIAN
Lugar:
Lausanne
Reunión:
Congreso; 1st International Conference on Calcined Clays for Sustainable Concrete; 2015
Resumen:
AbstractNumerous investigations on the immobilization of chromium in cement-based systems werecarried out in the recent years. The aim of this study is to analyze the influence of the crystallinityof kaolinite used to make calcined kaolinitic clay when are used in pastes for immobilization ofCr(VI). In previous study, it was found that the reactivity of kaolinitic calcined clays used aspartial replacement of Portland cement largely depends on the crystallinity of kaolinite in the rawclay. Calcined clays obtained from raw materials containing kaolinite with disordered structurepresents a very high pozzolanic activity allowing high-percentage replacement (30%) in blendedcements.In this study, pastes of blended cement with 15% and 30% by mass of two kaolinitic calcinedclays (order and disorder structure of kaolinite) were elaborated using a solution of 5000 ppm ofK2Cr2O7 and a solution-to-cementing material ratio of 0.50. The immobilization efficiency wasmeasurement by lixiviation test and the modifications in the hydrated phases was studied by Xraydiffraction and SEM/EDS analysis.The results shown that kaolinitic calcined clay from ordered kaolinite was more efficient thandisordered kaolinite to retention of Cr(VI), reaching values higher than that of PC-paste.