Banca de DEFESA: VANESSA RODRIGUES CAMPOS
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.STUDENT : VANESSA RODRIGUES CAMPOS
DATE: 14/07/2023
TIME: 08:30
LOCAL: Ambiente virtual
TITLE:
The application of functionally graded concept on the development of high-performance gypsum plaster
KEY WORDS:
High-performance gypsum plaster. Functionally Graded Materials. Mechanical properties. Water Resistance.
PAGES: 253
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:
The present work shows the feasibility of using the concept of functional graded materials (FGM) in the development of plaster components with high mechanical performance and resistant to the action of water. Variation in the composition and / or structure of the material, in a controlled manner, can contribute to the improvement of plaster properties, and to obtain a high-performance material. In this way, this work uses the technique of minimal wetting and the compaction of the wet plaster powder as a method of molding the plaster specimens, applying the FGM concept, to improve the performance of the plaster against the mechanical behavior and the action of Water. The molding of plaster by pressing pressure requires a mastery of the relationships between pressing pressure (P), mixture mass (M) and water / plaster ratio (a / g) for better control of properties in the application of functional gradation. The first stage of the experimental investigation involved the factorial design (2k) composed of three control parameters (P, M and a/g) in the evaluation of the properties of the plaster. The responses to be obtained were thickness (e), compressive strength (Rc); flexural tensile strength (Rt); hardness (D); modulus of elasticity (MOE), porosity (η) and resistance to water action. The second stage involved the use of the statistical design of mixture (screening strategy) in the evaluation of the effects of different additions (silica fume, industrial talc, fine granite rock and waterproofing) on the mechanical properties and resistance to the action of plaster water. The partial results obtained from the first stage showed an increasing linear correlation between pressing pressure and the analyzed responses, with the exception of porosity, which showed a decreasing linear correlation. The best combination obtained for plaster, molded under pressure, considering the analyzed parameters (P, M and a / g) were, respectively (15 MPa, 550 g and 0.18), which reached the values for Rc, Rt, MOE and η, respectively, of 53.5 MPa; 13.8 MPa and 20.0 Gpa and 20.1%. These results were superior to those achieved by plaster cast by the conventional method with Rc, Rt, MOE and η, respectively, equal to 17.2 MPa; 4.57 MPa and 8.32 Gpa and 46.8%, which showed an increase of about 64.38%. In the second stage, the partial results showed that there was a reduction of the mechanical resistance with the increase of the active silica content in the plaster. The analysis of the response surface identified talc and waterproofing as additions with the potential to be used in the analysis of functional gradation in plaster. It was concluded that the use of the complete factorial design and the statistical design of mixture allowed an optimization in the analysis of the answers, reduction of the number of experiments and repetitions, besides a simultaneous analysis of the factors and evaluation of the experimental error. For the final conclusion of this work, it will be necessary to carry out analyzes related to water resistance and functional gradation.
COMMITTEE MEMBERS:
Presidente - 2137887 - CLEBER MARCOS RIBEIRO DIAS
Interno - ***.925.915-** - PAULO ROBERTO LOPES LIMA - UEFS
Interno - 2178571 - RICARDO FERNANDES CARVALHO
Externo à Instituição - SERGIO FRANCISCO DOS SANTOS
Externa à Instituição - GLADIS CAMARINI
Externo à Instituição - NORMANDO PERAZZO BARBOSA