Banca de DEFESA: PABLO BORBA DE BARROS GOES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : PABLO BORBA DE BARROS GOES
DATE: 29/09/2023
TIME: 08:00
LOCAL: Pós-Graduação Engenharia Civil
TITLE:

Study of Cement Pastes Using Fines from Recycled Aggregates

KEY WORDS:

Fine particles, Construction and demolition waste, Microstructure, Compressive strength, Elastic modulus

PAGES: 190
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The construction industry is one of the largest generators of solid waste in the country. One way to recycle this material is through the production of recycled aggregates. However, this process generates a significant amount of fine particles, and the utilization of these particles is the focus of this study. The physical, chemical, and microstructural characteristics of these materials were analyzed at various degrees of fineness, as well as their use as fines in pastes with different replacement percentages. The predominant chemical element is SiO2, and X-ray diffraction (XRD) analysis indicates that the material is highly crystalline and devoid of amorphous halos. These particles possess irregular shapes and sharp edges that form cracks and notches resembling a V shape. The analyses of the fresh state of the pastes revealed that the partial substitution of cement with these fine particles influenced the cohesion of the mixtures. Mixtures with finer particles exhibited greater cohesion. Their hydration and setting time showed results similar to reference pastes containing only cement. In the hardened state, X-ray diffraction (XRD) analyses unveiled the presence of crystalline phases like alite, calcite, ettringite, portlandite, and quartz in the pastes. Thermogravimetry (TG) indicated a mass loss similar to that of cement. Compressive strength decreased with the substitution of these fine particles, while dynamic modulus of elasticity and porosity generally increased at substitution rates of 10%, possibly due to the microfiller effect. The pastes with RHP showed lower CO2 emissions than the reference paste. Based on the results, it can be concluded that a 10% substitution of cement with these fine particles may be a viable option, considering sustainability and strength.

COMMITTEE MEMBERS:
Presidente - 1152919 - ARNALDO MANOEL PEREIRA CARNEIRO
Externo à Instituição - EUDES DE ARIMATÉA ROCHA - UPE
Externa à Instituição - KAROLINE ALVES DE MELO MORAES - UFAL
Externo à Instituição - MARCIO SANTOS BARATA - UFPA
Externa à Instituição - MARYLINDA SANTOS DE FRANCA - TUM
Externa ao Programa - 3100969 - NATHALIA BEZERRA DE LIMA - null