Influência da temperatura e de tratamentos alcalinos na remoção dos extrativos da biomassa de madeira e seus efeitos na hidratação de pastas de cimento e de bioconcreto

Detalhes bibliográficos
Ano de defesa: 2019
Autor(a) principal: Pinto, Mônica Cristina
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal do Rio de Janeiro
Brasil
Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia
Programa de Pós-Graduação em Engenharia Civil
UFRJ
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/11422/13566
Resumo: In this work, wood sawdust has undergone different pre-treatments to reduce the amount of extractives. Therefore, the water temperature was varied between 25 and 95°C, the immersion time between 0.5 and 48h, and the sawdust mass:water volume ratio between 1:4 and 1:10, carrying out one washing cycle. Washing in alkaline solutions was also tested. Aiming the reuse of the washing water for the bioconcrete production, nanofiltration and reverse osmosis was tested. Initial and final setting time of pastes were determined by Vicat apparatus in order to evaluate the washing temperature, the immersion time, and the sawdust mass:water volume ratio. Isothermal calorimetry was used to evaluate cement pastes produced with water from the filtration processes. Adiabatic calorimetry and ultrasonic pulse velocity were performed in bioconcretes. The results showed that water heated at 80°C removes a greater amount of extractives. The amount of solubilized extractives with the immersion time of 30 min is sufficient. The use of reverse osmosis was efficient on the treatment of waste water and pastes produced with these waters presented isocalorimetric curves similar of the curve of paste with deionized water. The nanofiltration allowed the passage of the chloride ions and accelerated the hydration of the cement paste. LCA results showed that the best treatment was to wash the wood biomass in solution of 4% CaCl2. Overall, bioconcretes produced with wood biomass washed in solution of 4 % CaCl2 showed the best results.