Banca de QUALIFICAÇÃO: THIAGO MARQUES VIANA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : THIAGO MARQUES VIANA
DATA : 15/06/2018
HORA: 16:30
LOCAL: Centro Federal de Educação Tecnológica de Minas Gerais
TÍTULO:

High temperature behavior of ultra-high performance concretes reinforced with carbon nanotubes

PALAVRAS-CHAVES:

Ultra High Performance Concretes, Thermal Behavior, Multi-walled Carbon Nanotubes, High Temperatures

PÁGINAS: 75
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Civil
SUBÁREA: Construção Civil
ESPECIALIDADE: Materiais e Componentes de Construção
RESUMO:

Ultra high performance concretes (UHPC) are those whose blend leads to compressive strength greater than 150 MPa and considerably superior properties compared to high performance concrete and conventional concretes. In order to achieve such performance, the UHPC mixtures often rely on the presence of nanomaterials acting on the pore structure of the concrete, among which are carbon nanotubes (CNTs). The CNTs, due to their superior mechanical properties, are indicated for nano-reinforcement in the matrix of ultra-high performance cement composites. It is observed that few researchs involving mixtures of UHPC with incorporation of CNTs have been developed, although some recent studies indicate that its incorporation as reinforcements of the matrix can result in a significant improvement of the microstructure of the concrete. One of the greatest gaps in the knowledge about UHPC is its behavior when exposed to high temperatures, and the subject is an aspect of concern, since the phenomenon of spalling (explosive chipping at high temperatures) is characteristic of materials with very dense microstructure. In this sense, carbon nanotubes are good thermal conductors and can influence this behavior. In this context, the present research aims to study the behavior of UHPC reinforced with different percentages of CNTs (0.05 and 0.1% multi-walled carbon nanotubes), evaluating their properties comparing with a reference recipe without incorporation. In this sense, a recipe of UHPC was developed through the Modified Particle Packing Model of Andreassen. The recipe has carefully selected materials, such as cement, microsilica, rice husk ash, nanosilica, sand and superplasticizer (in the sense of obtaining workability even with a very low water cement factor of 0.28). The specimens of the material will be submitted to heating cycles and their effects will be evaluated through their mechanical behavior, occurrence of the spalling phenomenon, loss of mass and evaluation of the microstructure. To support the understanding of the results, properties of conductivity and thermal expansion will also be evaluated.

MEMBROS DA BANCA:
Interno - JUNIA NUNES DE PAULA
Externo à Instituição - MANUEL HOUMARD - UFMG
Presidente - PETER LUDVIG