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Autor(a/res): Ana Beatriz De Carvalho Gonzaga e Silva, Henrique Conde Carvalho de Andrade, Eduardo de Moraes Rego Fairbairn, Jose Claudio F. Telles
Resumo: This work presents a numerical modeling procedure to simulate the refractory concrete lining in fluid catalytic cracking units of oil refineries. The model includes the simulation of the anchors that reinforce the contact between the refractory concrete and the steel casing. For this purpose, the constitutive relations of an interface finite element are set to values that represent the homogenized behavior of the anchored interface. The parameters of this constitutive relation can be obtained by experimental tests. The model includes also multi-surface plasticity, in order to represent the behavior of the refractory concrete lining. Since the complexity of real case applications leads to high computational costs, the models presented here were implemented in a high-performance parallelized finite element platform. A case study representing a riser similar to the ones used by the refinery industry demonstrates the potential of the model.
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Autor(a/res): Amanda Pereira Vieira, Romildo Dias Toledo Filho, Luís Marcelo Tavares e Guilherme Chagas Cordeiro.
Resumo: Compressive strength evolution of high strength concrete with rice husk ash (RHA) was evaluated as a function of RHA particle size, porous structure and replacement content. RHA porous structure was investigated by N2 absorption isotherm and its effect on hydration evaluated using isothermal calorimetry and thermogravimetry. Results indicated that RHA particle size influenced compressive strength until 28 days, whereas at 91 days replacement content became the significant factor. Preserved porous structure of RHA particles besides improving hydration kinetics enabled its action as internal curing agent improving compressive strength at late age.
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