Banca de DEFESA: NATHALIA SOUZA TEIXEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NATHALIA SOUZA TEIXEIRA
DATE: 09/07/2026
TIME: 09:00
LOCAL: Videoconferência Google Meet
TITLE:

Synthesis and Characterization of Geopolymers from Natural Materials and Industrial Waste for Sustainable Cementitious Materials

KEY WORDS:

Geopolymers; Cementitious materials; Amorphization; Resistance; Waste; (CO2); GEO-RS; GEO-CC-4-15 and GEO-PE-CC.

 

PAGES: 136
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The increasing production of cementitious materials in the construction industry has significantly contributed to the rise in carbon dioxide (CO₂) emissions into the atmosphere. Among these materials, Portland cement stands out due to the high energy consumption associated with its production. In this context, geopolymers have emerged as a promising alternative to conventional cementitious materials. They exhibit relevant properties, such as high compressive strength, thermal insulation, and the possibility of being synthesized from natural materials and industrial wastes. In this study, geopolymers were synthesized from different aluminosilicate sources, including various kaolins, industrial wastes (kaolin waste, coal ash, glass powder, and aluminum silicate), and natural minerals such as diatomite and expanded perlite. The materials were characterized by X-ray Fluorescence (XRF), which was used to determine the chemical composition and the availability of the main oxides involved in the geopolymerization process. X-ray Diffraction (XRD) analyses were important for identifying the amorphous phase characteristic of the geopolymeric matrix. Complementarily, Fourier Transform Infrared Spectroscopy (FTIR) identified Si–O–Si bonds, hydroxyl groups (O–H), and a low occurrence of carbonates associated with efflorescence. Furthermore, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the internal and external morphology of the geopolymers, showing the presence of pores and partially reacted particles. Textural analysis by gas adsorption demonstrated that the specific surface areas of the aluminosilicate sources directly influenced the pore distribution within the geopolymeric matrices. In addition, ²⁷Al and ²⁹Si Nuclear Magnetic Resonance (NMR) spectroscopy enabled the identification of Q⁴(nAl) structural units and the coordination environments of aluminum, confirming the formation of the three-dimensional geopolymeric network. Finally, compressive strength tests performed on geopolymers produced from kaolin waste (GEO-RC), cover kaolin (GEO-CC-4-15), and expanded perlite combined with cover metakaolin (GEO-PE-CC) demonstrated their potential for application as non-structural construction materials, such as masonry bricks and thermal insulation products. These results demonstrate the technical feasibility of utilizing wastes as sustainable raw materials for the production of geopolymers with lower environmental impact and reduced CO₂ emissions.

COMMITTEE MEMBERS:
Externo à Instituição - ANA PAULA DE CARVALHO TEIXEIRA - UFMG
Presidente - 349770 - DULCE MARIA DE ARAUJO MELO
Interno - 1350249 - RUBENS MARIBONDO DO NASCIMENTO
Interna - 1308577 - SIBELE BERENICE CASTELLA PERGHER