Banca de DEFESA: JOSÉ VINICIUS FIRMINO DANTAS LEITE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOSÉ VINICIUS FIRMINO DANTAS LEITE
DATE: 24/04/2026
TIME: 14:00
LOCAL: SALA 406 PGTEC
TITLE:

THERMAL AND ELECTROMAGNETIC IMPACT OF EXPANDED VERMICULITE IN COATING MORTARS WITH DIFFERENT THICKNESSES

KEY WORDS:

Electrical permittivity; electromagnetic shielding; thermal conductivity; expanded vermiculite; porosity.

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

The growing demand for energy efficiency and the emergence of smart buildings have imposed a necessity for construction materials with enhanced thermal performance and electromagnetic shielding. In this scenario, the incorporation of lightweight and porous aggregates into cementitious mortars has emerged as a promising solution. Expanded vermiculite, a lightweight and highly porous silicate, is a prominent material recognized for conferring electromagnetic polarization and superior insulating properties. This study presents an experimental investigation aimed at quantifying the impact of increased void ratios on the thermal and electromagnetic properties of mortars through the partial and total replacement of conventional aggregate with expanded vermiculite, as well as evaluating the effects stemming from varying coating thicknesses. Specimens with different thicknesses were molded using volumetric ratios of 1:3 and 1:4, with vermiculite replacement rates of 25%, 50%, 75%, and 100%. The samples underwent physical, thermal, and electromagnetic characterization, with thermal conductivity and electrical permittivity serving as the primary parameters for evaluating thermal performance and electromagnetic shielding, respectively. The results revealed a significant reduction in thermal conductivity—reaching 80% in composites with total replacement—and a gradual increase in electromagnetic shielding as the expanded vermiculite content in the mortar increased. This improvement proved to be directly proportional to the increase in the void ratio and the hygroscopic characteristics induced by the vermiculite. Variations in cement consumption between the mixes and the different thicknesses did not produce significant changes in the evaluated properties, indicating that the porosity of the cementitious matrix is the dominant factor. Microstructural analysis evidenced poor adhesion between the cement paste and the vermiculite lamellae. Finally, the study establishes a strong correlation between the results of thermal conductivity, electrical permittivity, and void ratios, validating the use of low-cost electromagnetic sensors for measuring thermal properties and demonstrating their effectiveness in determining the void ratio of cementitious composites.

COMMITTEE MEMBERS:
Presidente - ***.403.354-** - KLEBER CAVALCANTI CABRAL - UFERSA
Externa à Instituição - JANAINA SALUSTIO DA SILVA - UFERSA
Externa à Instituição - RÍSIA AMARAL ARAÚJO - IFRN