Navegando por Assunto "Materials and process"

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Síntese e caracterização de geopolímeros, a partir de argila, caulim ferruginoso e cinzas volantes - classe c
(Universidade Federal do Pará, 2021-08-12) PREZA, Carmen Raiza Aires Soares; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
The high demand in the civil construction sector has caused a negative scenario for the environment. With this, researches arise with the objective of discovering sustainable alternatives to the existing technology, because, it is known that over the years, the concern with nature was significantly lost. With that in mind, the situation can be softened with some of the techniques that have been around for millennia and are still relevant. Studies on geopolymers are growing, especially in developed countries. The main application of this material, composed of minerals and industrial residues, is the replacement of Portalnd cement. Thus, this work aimed to produce geopolymers with superior physicochemical properties. The elaboration of geopolymers was directed from different concentrations of clay/flying ash and ferritic kaolin/flying ash. The raw materials were analyzed in natura and calcined at 600 ºC/2 hours and 800 ºC, using Xray diffraction, X-ray fluorescence and laser particle size analysis. The results showed that the raw materials are technologically viable for the study, due to their SiO2 and Al2O3 contents, being: 63.89% and 16.65% for clay; 38.57% and 36.85% for ferritic kaolin; and 42.53% and 16.40% for fly ash, respectively. The raw materials presented fine grain sizes, being more reactive. Geopolymers A3 (80% clay/20% fly ash) and C3 (80% kaolin/20% fly ash) showed the best results for compressive strength, 13.19 MPa and 31.22 MPa, in the 28th day, respectively. The values found are within the limits found for some Portland cements.