Navegando por Assunto "Silica fume"

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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)
Influência da substituição parcial do cimento por sílica ativa nas propriedades de argamassas com agregado reciclado de concreto.
(Universidade Federal do Pará, 2023-04-13) CRUZ, Welington de Sousa; CORDEIRO, Luciana de Nazaré Pinheiro; http://lattes.cnpq.br/9126233381230999; https://orcid.org/0000-0001-7931-4042
The main objective of this dissertation is to evaluate the effect of partial replacement of cement by silica fume on the physical-mechanical behavior of coating mortars with recycled concrete aggregate (RCC) and to analyze its environmental impacts, considering CO2 emissions and energy consumption. generated in the production of mortar raw materials. We tried to evaluate the influence of recycled aggregates in proportions of 1:3 and 1:4 (in mass) by partially replacing the natural aggregate with 0%, 30% and 50% RCC, and each of these groups was subdivided with substitutions partial cement by silica fume in the contents of 0%, 5%, 10% and 15%. The results allow concluding that the increase in the recycled aggregate content in the mortars impacts on its rheology and reduces its mechanical properties compared to the reference one, being softened with the incorporation of silica fume. Regarding environmental impacts, cement was the main cause of impacts. Samples R0S15 present the highest cement consumption in both the 1:3 and 1:4 mixes and, therefore, generate greater impacts. However, the impacts generated per unit of resistance show an inverse situation. Therefore, despite generating higher CO2 emissions and energy consumption, their contribution to resistance reflects greater sustainability.