Banca de DEFESA: RICARDO AUGUSTO DOS SANTOS HORTA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RICARDO AUGUSTO DOS SANTOS HORTA
DATE: 14/12/2020
TIME: 14:00
LOCAL: https://conferenciaweb.rnp.br/webconf/junia-nunes-de-paula
TITLE:

Rheological behaviour and mechanical properties of cement paste with addition of graphene oxide.

KEY WORDS:

Graphene oxide. Nanomaterials. Rheological behavior. Mechanical properties. Cement composites.

PAGES: 117
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

The addition of graphene oxide (GO) in cementitious materials allows to obtain more resistant and durable composites, with less pollutant load associated with their production. Previous research has shown that the addition of nanomaterials to the cement paste can cause an increase in rheological parameters such as plastic viscosity and yield stress. This study aimed to investigate the rheological behavior, thermal profile in hydration and mechanical properties of cement pastes with the addition of GO. In order to fulfill this objective, tests were carried out with GO produced and patented at CTNano / UFMG (Technology Center for Nanomaterials and Graphene at the Federal University of Minas Gerais) in the contents of 0.03% and 0.05%, on cement pastes classe CP-III-40-RS. Two methods of analysis of rheological behavior were used, the mini-slump and the rotational flow rheometry. In the mini-slump test, reductions in the spreading radius of 20.88% (0.03% GO) and 42.94% (0.05% GO) were obtained. In the rotational flow rheometry, increases in plastic viscosity of 60.78% (0.03% GO) and 125.49% (0.05% GO) were obtained, and in the yield stress of 49.77% (0.03% GO) and 82.24% (0.05% GO). In the calorimetry test, increases were observed in the maximum temperature and in the initial hydration heat of the cement pastes due to the addition of GO, which indicates that this nanomaterial alters the kinetics of the cement hydration reaction. In the three-point flexion test, the Digital Image Correlation (DIC) method was used to correlate the deformation stages of the specimens, obtaining the load versus vertical displacement curves. The addition content of 0.05% GO produced the best results in three of the four mechanical properties and fracture parameters analyzed. For this content, at 28 days, increases in modulus of elasticity, tensile strength in flexion and fracture toughness of 19.40%, 16.86%, 27.37%, respectively, were obtained. For the addition content of 0.03% GO, an increase in fracture energy of 397.37% was obtained at 28 days. Given these results, it can be inferred that GO has the potential to be applied in civil construction, aiming at improving the mechanical properties and fracture parameters of cement pastes.

BANKING MEMBERS:
Presidente - JUNIA NUNES DE PAULA
Interno - CONRADO DE SOUZA RODRIGUES
Externo à Instituição - MANUEL HOUMARD - UFMG
Externo à Instituição - JOSÉ MÁRCIO FONSECA CALIXTO - UFMG