Microconcreto de alto desempenho com fibras de polipropileno
Nenhuma Miniatura disponível
Data
2018-08-31
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
The microconcrete can be defined as a specific type of concrete in which the presence of small aggregates is
predominant and can be used in light prefabrication, that is, in thin section structural elements. Thus, this
work aims to evaluate the behavior, in the fresh and hardened states, of the high performance microconcrete
with the use of polypropylene fibers. To do so, two fiber dimensions were used: a short 12 mm long, usually
used to reduce cracking by plastic retraction, and another fiber of 54 mm, which has a structural function,
contributing to improve the tensile strength of material. The fiber contents, in relation to the microconcrete
volume, were 0.1%, 0.2%, 0.3% and 0.4% for the microfiber, 0.3%, 0.4% and 0, 5% for the macrofiber and
for the hybrids, these being composed of 30% microfiber and 70% macrofiber. Part of the cement was
replaced by active silica (SA) and fly ash (CV), in proportions of 7.5% for each one. The tests in the fresh
state showed that the fibers reduced the workability, being this more accentuated in the microconcretes with
addition of microfibres. Fibers contributed to increase fracture energy; this fact has shown that the
application of the fibers in cementitious elements is promising in order to inhibit the brittle rupture and to
provide ductile behavior to the element. The contents of 0.3% and 0.4% of microfibers presented a marked
increase in porosity and, consequently, an increase in carbonation depth. The tests demonstrated that one
must advance in researches with the use of hybrid mixtures and composites with contents of up to 0,12% of
microfibres. The addition of the PP fibers provided positive mechanical results for additions of up to 0.1%
of microfibers and for additions of up to 0.12% of microfibers in the hybrid composites. In terms of
durability presented similar results, except for the additions from 0.2% of microfibers that reasonably
elevated the carbonation depth. The high performance of the microconcrete was demonstrated by the results
of axial compressive strength around 50 MPa, and by the increase of the tenacity provided by the addition
of the PP fibers.
Descrição
Palavras-chave
Citação
SILVA, R. V. Microconcreto de alto desempenho com fibras de polipropileno. 2018. 118 f. Dissertação (Mestrado em Geotecnia, Estruturas e Construção Civil) - Universidade Federal de Goiás, Goiânia, 2018.