Navegando por Assunto "Mechanical Properties"

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Acesso aberto (Open Access)
Comportamento mecânico dos efeitos da substituição parcial do cimento por sílica ativa em eco concretos
(Universidade Federal do Pará, 2016-05-27) PIRES, Gabriela de Oliveira; PICANÇO, Marcelo de Souza; http://lattes.cnpq.br/4535052395600357
The exploitation of natural resources for construction purposes generates millions of tons of waste, thus being developed several studies to recycle this waste and the use of construction waste (CW) in the produced concrete. The pig silicon-iron production industry also produces tons of waste, silica fume, which can also be used in concretes and mortars in replacement / addition relative to cement. The main focus of this research is the study of the interaction of concrete produced with natural aggregates and aggregate coarse recycled concrete (CRCA) with partial replacement of silica fume relative to cement. The main objective of this dissertation is to analyze the influence of different levels of silica fume on the mechanical behavior of concrete produced with natural and concrete aggregates produced with different levels of ACRC. The experimental program was divided into three stages, it was first made the characterization of the material and processing of ACRC. The second phase consisted of the elaboration of the traits for different types of concrete by IPT/EPUSP method, and the same divided into three groups with 0%, 25% and 50% use of AGRC in partial replacement of coarse aggregate, each subdivided group levels with 0%, 5% and 10% replacement of cement with the silica fume. After curing the concrete were tested at the ages of 28 and 91 days with the following assays: compressive strength, splitting tensile strength and static modulus of elasticity. With the results can be concluded that mechanical performance of concrete with recycled concrete aggregates increased significantly in relation to the concrete reference (without silica) with respect to compressive strength and tensile and modulus of elasticity.
Acesso aberto (Open Access)
Resíduo do lodo da estação de tratamento de água da Região Metropolitana de Belém em substituição parcial ao cimento Portland em argamassa
(Universidade Federal do Pará, 2019-04-25) CUNHA, Bruna Baia da; PICANÇO, Marcelo de Souza
As a result of the growth of cities and the greater demand for quality of life, the demand for drinking water has increased in recent decades. Like any industrial process, the production of water for human use generates large quantities of by-products, being the main designated residue of waste, sludge or sludge of Water Treatment Station (WTPS). So far, the most common destination for the WTPS is the watercourse, although it is considered a solid waste. These factors motivate research aimed at alleviating the problems caused by incorrect waste disposal in the environment. In this sense, the present paper presents an alternative proposal for the disposal of WTPS in mortar, partially replacing cement, whose extraction and employment also cause environmental impact. The WTPS was used in the mortar with the least possible alteration of the residue, that is, its in natura use to avoid energy expenditure and to enable its use. The characterization of the materials used, as well as the physical, chemical, mineralogical and thermal characterization of the sludge extracted from WTP Bolonha, located in the metropolitan area of Belém, was carried out. The analyzes provided data that were the basis for investigations of viable applications for the residue. The first investigation studied its use as pozzolan in Portland cement, for which the tests that analyzed its potential reactivity with lime and cement were carried out. The investigation of the pozzolanic activity, both with lime and cement CP II-F-32, showed that mortars with replacement contents obtained lower results than required by the respective standards, discarding their use for this purpose. The second research analyzed the effects of the use of the residue as a filler in Portland cement, the reference mortar (without addition of sludge) and traces with additions of 6, 8 and 10% were used. In the compressive strength the 6% replacement content of the cement Portland CP I-25 by WTPS produced a resistance increase of 8,93% at 7 days and 3,24% at 28 days of age, in relation to the reference mortar, besides absorbing 7,81% water less than conventional mortar. Although the use of sludge occurs in small quantities, its use is feasible, since its incorporation will reduce the consumption of the raw material required for the production of mortar.