Contribuição ao estudo reológico de pastas cimentícias com adição de resíduo do beneficiamento de rochas ornamentais

• Autor(a) principal: Sato, Vanessa Yumi
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4002
• topic: solid wastes; slurry; ornamental rocks; cementitious paste; consistency; workability; rheology; resíduos sólidos; lama; rochas ornamentais; pasta de cimento; consistência, trabalhabilidade; reologia; Engenharia Civil; Resíduos sólidos; Reaproveitamento (Sobras, refugos, etc.).; Rochas ornamentais; Cimento; Reologia; 624

Brazil is one of the major producers and exporters in the ornamental stone sector. In contrast, the production and processing of ornamental stones result in large volumes of waste material in a form of slurry, generally disposed in settling ponds or landfills inappropriatedly. Many researches are being conducted aiming the reuse of this waste material in cementitious matrices. In the rheology field, there are still few national studies that use rheological parameters to determine the behavior of Portland cement based cementitous matrices. Thus, the goal of the present work is to characterize rheologically the behavior of cement pastes with and without addition of ornamental stone waste in its natural condition. Cement pastes were produced with three water-to-cement ratio (0.45; 0.55; 0.65) and four percentages of residue (0%, 5%, 10%, 15%) and subjected to flow and oscillatory (strain sweep) tests. The testing results for the waste material characterization, RBRO presented with a fineness and material density close to the cement, having low reactive activity, indicating that the residue can be used as an inert mineral addition in cement matrix. In the rheological characterization of the studied cement pastes, it was observed that the samples behaved as a non-Newtonian fluid, pseudoplastic and thixotropic. With respect to the oscillatory testing results, the cementitious pastes without residue addition and with the addition of 5% RBRO had similar critical deformation regardless the analyzed w/c ratio, showing a tendency to support greater deformation. It is also realized that there is a negative correlation between the trend obtained in both compression resistance and elastic modulus G 'and between the consistency and yield strength of the samples. This confirms that the residue behaved like a filler, making the cement paste more viscous and decreasing its workability, since it fills the inter-granular voids in the matrix. Therefore, it can be concluded that there is a potential to the use of the ornamental stone waste material in cement matrices, giving a better destination to this waste.