Banca de DEFESA: SÂMARA FRANÇA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : SÂMARA FRANÇA
DATE: 25/05/2023
TIME: 08:00
LOCAL: https://conferenciaweb.rnp.br/sala/augusto-cesar-da-silva-bezerra
TITLE:

Alkali-activated materials from sugarcane bagasse ash

KEY WORDS:

Alkali activated materials, sugarcane bagasse ash, sustainability.

PAGES: 136
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

The production of Portland cement shows significant importance for social and economic development of a country; however, it also generates environmental impacts from the extraction of raw materials to the production of clinker. Despite the effects, the demand for Portland cement is still growing in developing countries such as India, China, and Brazil. Faced with this impasse, research for developing alternative materials to Portland cement is growing worldwide. Among these researches, those related to alkali-activated materials (AAMs) stand out. AAMs are considered more sustainable than Portland cement because they emit less CO₂ during production. In addition, the raw materials used in its development are generally residues or rejects from other industrial processes. Sugarcane bagasse ash (SCBA) is an example of residue generated on a large scale in Brazil and with great potential for use in producing AAMs. Therefore, the present work sought to develop AAMs using SCBA as an exclusive precursor. For this, the reactivity of the ash was evaluated through chemical tests. Subsequently, the material's viability was verified through physical, mechanical, and durability tests. As a result, it was found that alkali-activated pastes produced from SCBA as an exclusive precursor have a structural constitution similar to pastes made from traditional precursors. In addition, it was concluded that SCBA is a viable exclusive precursor since the pastes achieved significant mechanical strength (21.39 MPa), low bulk density (1.74 g/cm³), and low porosity (3.54%) at 28 days of cure. Regarding durability, it was concluded that the matrices produced from SCBA as an exclusive precursor have excellent resistance to acid attack since they present an increase in resistance to compression after seven days of immersion in sulfuric acid. However, regarding the alkali-silica reaction, it is concluded that the methodologies of the Brazilian and US standards are not adequate for AAMs produced exclusively from SCBA, since the immersion of the test specimens in the tanks occurs before the consolidation of the matrix or which results in excessive expansion of the material. Furthermore, it is concluded that the porosity of the produced pastes is directly proportional to the susceptibility to aggressive agents of the tested mortars.

COMMITTEE MEMBERS:
Presidente - AUGUSTO CESAR DA SILVA BEZERRA
Interno - PAULO HENRIQUE RIBEIRO BORGES
Externa à Instituição - MARIA TERESA PAULINO AGUILAR - UFMG
Externo à Instituição - JOSÉ MARIA FRANCO DE CARVALHO - UFV