Banca de DEFESA: Raquel Pereira Batista

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : Raquel Pereira Batista
DATA : 01/02/2018
HORA: 09:30
LOCAL: Centro Federal de Educação Tecnológica de Minas Gerais
TÍTULO:

INTERFERÊNCIA DA COMPOSIÇÃO DA MATRIZ NO DESEMPENHO MECÂNICO DE COMPÓSITOS ÁLCALI-ATIVADOS REFORÇADOS COM FIBRAS CURTAS DE PVA

PALAVRAS-CHAVES:

Geopolymers, alkali-activated materials, PVA fibers, metakaolin, silica fume.

PÁGINAS: 95
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Civil
SUBÁREA: Construção Civil
ESPECIALIDADE: Materiais e Componentes de Construção
RESUMO:

Alkali-activated materials (AAM), similarly to Portland cement based mortars and concrete, are brittle materials that may have their mechanical behavior improved using fibers. They are currently the subject of increasing interest and research as they present superior performance in many aspects when compared to traditional products. Several types of fibers have already been employed in the production of alkali-activated composites. Poly vinyl alcohol (PVA) seems to be a good choice due to its excellent interaction with the matrix and high stability in alkaline environments. This research investigates the effects of the amount of soluble silica present in the activator on the mechanical and durability-related performance of PVA-reinforced alkali-activated mortars. The composites studied were obtained from the alkaline activation of metakaolin (MK) and in each formulation this precursor material was partially replaced by silica fume (SF), with the purpose of adjusting the SiO2/Al2O3 molar ratio of the matrix. The activator solution used consists of sodium silicate (Na2SiO3), sodium hydroxide (NaOH) and the dissolved SF. Two SiO2/Al2O3 molar ratios were employed: 3.0 and 3.8. The other activating parameter, i.e. Na2O/SiO2, Na2O/Al2O3 and H2O/Na2O molar ratios were held constant, as well as the amount of aggregates used in each formulation. All formulations were reinforced with 2% vol. of PVA fibers. The mechanical properties investigated were compressive and flexural strength. The Young's Module of the mortars was also determined. Apparent porosity tests were used to give an estimation of the durability of the AAM. Preliminary results indicate that the mechanical performance of PVA-reinforced AAM is influenced by the SiO2/Al2O3 molar ratio of the matrix. In addition, the toughness of the composites may be influenced mainly by the source of soluble silica in the activator and by the apparent porosity of the matrices. 

MEMBROS DA BANCA:
Externo à Instituição - FERNANDO SOARES LAMEIRAS - UFMG
Interno - FLAVIA SPITALE JACQUES POGGIALI
Externo à Instituição - FLAVIO DE ANDRADE SILVA - PUC - RJ
Presidente - PAULO HENRIQUE RIBEIRO BORGES