Desenvolvimento de agregados leves a partir de resíduo de scheelita, lodo de esgoto e cinza da casca do arroz

• Ano de defesa: 2019
• Autor(a) principal: Souza, Maelson Mendonça de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA CIVIL
• Palavras-chave em Português: Agregado leve; Resíduo da produção de scheelita; Lodo de esgoto; Cinza da casca do arroz; Reutilização; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/28162

The use of lightweight aggregates (LWAs) is a consolidated practice in the construction industry. Its characteristics are relevant to various engineering services. However, commercial manufacture of this product is still quite limited. Brazil, for example, has only one LWA factory, located in the state of Sao Paulo. Over the years, the use of expandable clays has been supporting national production; however, the gradual scarcity of natural resources requires the use of more sustainable practices. Thus, this research aims to develop LWAs suitable for use in engineering works and services, from the use of scheelite residue (RPS), sewage sludge (SS), and rice husk ash (RHA), replacing two distinct types of clay. Recent studies have shown that the production of these three wastes is increasing in several countries. However, in opposition to this scenario, the control agencies have been increasing the strictness of environmental laws, making various traditional methods of disposal unfeasible. Thus, this research can help in the preservation of natural resources and in reducing the environmental impacts caused by such residues. Specifically, we also sought to establish comparative analysis between manufactured and commercially available LWAs, and to evaluate the effects of sintering temperature and raw materials on the properties of sustainable LWAs. All the raw materials were benefited and later analyzed by laser granulometry, scanning electron microscopy (SEM), X-ray fluorescence (FRX), X-ray diffraction (XRD) and simultaneous thermal analysis (STA). Then 50 distinct mixtures were formulated from the substitution of clay for up to 100% of residues. The samples were dried and then sintered at 1100, 1150, 1200 and 1250 ° C. The manufactured aggregates were then characterized by analysis of swelling index (BI), mass loss (LOI), particle density (ρd), water absorption (WA24H), crush strength (S), mineralogical composition, thermogravimetric behavior and microstructure. Finally, the feasibility of using manufactured LWAs was evaluated by comparative analysis with commercial LWAs. The resulting aggregates showed a maximum (BI) of 77.44%, (LOI) of up to 43.6%, (ρd) ranging from 0.63 to 2.01 g / cm³, (WA24H) of a minimum of 0.7%. and (S) up to 17.3 MPa. In all, 102 specimens have demonstrated properties at least similar to those found in commercial LWAs, showing the possibility of use in at least 1 major application of this product in engineering works and services. The results obtained in this experimental program reveal that it is technically feasible to use RPS, SS and RHA to produce lightweight aggregates with properties suitable for major commercial LWA applications. In addition, it was found that sintering temperature and raw material proportions exert a strong influence on the main properties of LWAs, and that the prediction of swelling based on the chemical composition of the mixtures proved to be unreliable when applied to elaborated LWAs. with RPS, SS and RHA.