Banca de DEFESA: LUANNA CARLA MATIAS PAIVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : LUANNA CARLA MATIAS PAIVA
DATA : 21/12/2018
HORA: 08:30
LOCAL: Auditório do Laboratório de Cimentos da UFRN
TÍTULO:

Effect of the addition of basalt fibers on the fracture strength of oilwell cements

PALAVRAS-CHAVES:

Basalt fiber; Oil well cement; Portland cement; Silica flour

PÁGINAS: 107
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
RESUMO:

The dispersion of short fibers to oil well Portland slurries may improve the compressive strength and fracture energy of the hardened cementing material. A study was carried out to investigate the effect of the addition of ball-milled basalt fibers to Portland slurries. Initially, samples were prepared with and without silica flour (40% BWOC) and milled basalt fibers (5% BWOC) in the composition, and cured for 7 days under different Bottom Hole Static Temperatures (BHST): 80 °C (176 °F) and 300 °C (572 °F). Subsequently, samples were prepared with silica flour (30%, 35% and 40% BWOC) and milled basalt fibers (5% BWOC), in addition to silica blend (30% silica flour and 15% metacaulim) and a higher content of milled basalt fibers (10% BWOC) in the composition, and cured for 7 days under 80 °C.The mechanical properties and the microstructure of the hardened pastes were evaluated by compressive strength tests, X-ray diffraction and scanning electron microscopy. The results showed that milling basalt fibers was a cost efficient method to adjust the length of the basalt wool fibers assuring slurry mixing and, therefore, adequate pumpability. The roughness of the fiber obtained after milling may be responsible for a higher fiber-matrix adhesion. The combined addition of silica flour and basalt fibers improved the fracture energy of samples cured at 80 °C, therefore below the strength retrogression temperature. The effect of the silica flour content (30%, 35% and 40% BWOC) combined with milled basalt fibers (5% BWOC) resulted in a better fracture energy increase of ~36 J to 45 J for addition with 30% silica. However, The effect of the milled basalt fibers content (0%, 5% and 10% BWOC) combined with silica flour (30% BWOC) resulted in fracture energy increases of ~ 36 J - 45 J - 52 J, to the measure that fiber content added was increased. Curing at 300 ºC resulted in significant fiber consumption by pozzolanic reactions that could not be prevented by the addition of silica flour. Therefore, ball-milled basalt fibers can be a cost-efficient and environmental-friendly solution to improve the mechanical properties of oil well cement slurries used below the retrogression temperature.

MEMBROS DA BANCA:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Externo à Instituição - ERICA NATASCHE DE MEDEIROS GURGEL PINTO - UFERSA
Interno - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Externo à Instituição - KLEBER CAVALCANTI CABRAL - UFERSA
Externo à Instituição - ZODINIO LAURISA MONTEIRO SAMPAIO - UNIFACEX