Viabilidade técnica da argila calcinada como material cimentício suplementar

Abstract

This study evaluates the effect of the addition calcined clay addition on the rheological behavior, mechanical performance and microstructure of cementitious materials. the in natura clay collected in the Curiuva city - PR, Brazil, was fired at 800°C during 1 hour, cooled abruptly, and milled during 8 hours. The chemical and mineralogical compositions of in natura and calcined clays, Portland cement and hydrated lime were obtained by fluorescence and X-ray diffraction, and thermogravimetric analysis. The physical characterization of calcined clay, Portland cement and hydrated lime were determined by laser granulometry, specific surface area by gas adsorption (BET), and density by pycnometry of liquids. The rheological behaviors of the cement pastes composed of cement and calcined clay,as well as the calcium hydroxide with calcined clay paste were evaluated by rotational rheometry. The mechanical performance was evaluated through the compressive strength of one mortar composed of 72% of calcined clay and 28% of calcium hydroxide.andanother mortar composed of 75% of Portland cement and 25% of calcined clay. In addition, the influence of a thermal cure at 100°C for 24 hours on the aforementioned mortars was also evaluated. The microstructure was evaluated by thermogravimetric analysis, x-ray diffraction and scanning electron microscopy with EDS.