Navegando por Autor "CARDOSO, Dilson Nazareno Pereira"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Determinação do ponto de carga zero da bauxita da região nordeste do Pará
(2012-12) PINTO, Rayssa Luana da Silva; SILVA, Kelly Cristina Sarmento da; CARDOSO, Dilson Nazareno Pereira; MACÊDO, Emanuel Negrão; FELIPE, Augusta Maria Paulain Ferreira
In the northeast of Pará, Brazil, the transport of bauxite pulp is through pipeline, being the viscosity a parameter which can interfere in the pumping. This study illustrates the influence of pH on pulp rheology through of determination of the zero point of charge. Were done particle size analysis, SEM, EDS, potentiometric tests testing ammonia chloride as indifferent electrolyte and rheological tests at different pH values. The results revealed that ammonia chloride can be used as indifferent electrolyte and showed a decrease in viscosity when there is far of the zero point of charge.
Acesso aberto (Open Access)
Influência do teor de cinza volante na reologia de argamassa de assentamento: fabricado com reciclagem de resíduos
(Universidade Federal do Pará, 2014-02-05) CARDOSO, Dilson Nazareno Pereira; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; FELIPE, Augusta Maria Paulain Ferreira; http://lattes.cnpq.br/8871741271063047
The mortars may be considered as a set of solid suspended particles (aggregate), water and binders (cement slurry). Thus, rheological behavior during cure can be influenced by factors such as particle size, composition and content of corporate water. This study investigated the rheological properties of six mortars, depending on the content of fly ash as a pozzolanic activity material, partial replacement of cement. This type of cement used as an aggregate base construction of the residue (RCC) which was characterized by diffraction and fluorescence X- rays. Were formulated for the mortars with addition of rheological tests residue construction (RCC) in proportions of 95, 90, 85, 80, 75 and 70% fly ash (CV) 0, 5, 10, 15, 20 and 25 % to 5 % of ordinary Portland Cement (PC - II and 32), and in each sample was incorporated 35 % water. We used the model VT 550 viscometer with sensor type coaxial cylinders SV1 - Haake temperature of 28 ºC. To evaluate the curing time of the material has scheduled a constant shear rate 53.4 s-1 for 1h and 45 min, with rated torque at intervals of 15min. For the development of flow curves and hysteresis curves, we used the shear rate between 0 and 600 s-1 in the time interval of 120 s. The results showed that the incorporation of fly ash is the main factor for increased torque on the curing time of mortar and behavior change reópetico for thixotropic, the traits analyzed. The experimental data of the proposed formulations are adjusted to the rheological model of Herschel - Bulkley.
Acesso aberto (Open Access)
Influência do uso de resíduos industriais nas propriedades mecânicas e reológicas de argamassas utilizadas na indústria da construção civil
(Universidade Federal do Pará, 2019-03-21) CARDOSO, Dilson Nazareno Pereira; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/1711061955509303
The general objective of this work was to develop alternative and usable materials within the construction industry, addressing a logic of recovery and reuse of solid waste, generated from construction and demolition construction sites, as well as the reuse of waste generated from the construction industry mining industry and mineral processing. Were used in the work the residue of construction (RCC), residue of sulfide copper ore (RMCS) and the waste of circulating fluidized bed boilers from the combustion of coal to fly ash (CV). The samples of these materials showed appropriate characteristics, such as recycled fine aggregate within the NBR 7211 standard. The materials were subjected to physical and chemical characterization through laser particle size analysis, x-ray fluorescence (FRX), diffraction and x-ray (DRX).). The mortars produced were studied in the free state, that is, without additives and also within the insertion of polymeric organic additive polyvinyl acetate (PVA) and Styrene Butadiene (SBR). The obtained mortars were physically characterized through the analysis of apparent porosity, water absorption, apparent specific mass and resistance to axial compression. Thermal analyzes of (TG and DTG) and scanning electron microscopy - SEM were also performed. In the fluid state rheological tests were performed to evaluate its behavior according to time (thixotropy), workability and the most representative rheological model for its flow. The developed materials presented technical properties approved by the ABNT standards, making them suitable for certain types of applications, in terms of laying and covering of walls, floors and ceramic tiles, respecting the technical characteristics of these materials.