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- Avaliação do desempenho de argamassas com areias do leito fluidizado de centrais de queima de biomassaPublication . Gonilho Pereira, Cristiana; Deloroso, Júlia; Betioli, AndreaOs impactes associados ao fornecimento de recursos naturais para a atividade industrial são cada vez maiores, quer a nível ambiental quer a nível económico. A utilização e transformação destes recursos gera impactes no meio ambiente, nomeadamente, através da produção de resíduos. Torna-se imprescindível promover a utilização de resíduos como matérias-primas alternativas, implementando estudos que perspetivem soluções concretas de valorização. No setor da Construção Civil são vários os estudos sobre o potencial da utilização de resíduos de diferentes naturezas. À data, despertam particular interesse os resíduos provenientes das centrais de queima de biomassa - cinzas volantes e as areias do leito fluidizado -, à semelhança do ocorrido com os materiais homólogos provenientes das centrais de queima de carvão. O objetivo tem sido a avaliação do potencial de substituição parcial de cimento e/ou de agregado fino na produção de argamassas e betão. Com o objetivo de contribuir para o estado dos conhecimentos sobre o potencial de utilização das areias do leito fluidizado de caldeiras de queima de biomassa, o trabalho apresenta um estudo comparativo entre argamassas de cimento produzidas com agregado natural e argamassas de cimento produzidas com resíduo, em substituição parcial do agregado natural. Mais, e com o objetivo de aferir a viabilidade de utilização do resíduo nas condições de fornecimento, o trabalho apresenta também um estudo comparativo entre argamassas de cimento produzidas com resíduo conforme fornecimento e argamassas de cimento produzidas com resíduo com granulometria e baridade manipuladas. Os três tipos de argamassas foram caracterizados, aos 7 e aos 28 dias, através de ensaios de caracterização mecânica e física. O estudo permitiu concluir que há melhorias do desempenho das argamassas com substituição parcial do agregado natural pelo resíduo, que são mais evidentes quando este apresenta granulometria e baridade manipulada.
- Produção e caracterização de argamassas com RCD reforçadas com fibra de sisalPublication . Soares, Edilson; Bravo, Miguel; Gonilho Pereira, Cristiana; Jasper, Catarina MarchiSustainable development is a crucial political and social project for humanity, encouraging the search for sustainable solutions. In materials engineering, the use of low-cost and low-energy materials is essential. This research addresses environmental and sustainable development issues, focusing on the use of Construction and Demolition Waste (CDW). The use of CDW prevents its irregular disposal in landfills, increasing recycling in Portugal. In addition, the Agave Sisalana plant, abundant in Brazil, especially in Bahia, offers usable fibers and pulp. Mortar with CDW and sisal fibers is sustainable, composed of recycled and abundant materials. Nine types of mortars were produced: cement with fine natural aggregate (reference), replacing 50% and 100% of the fine natural aggregate with fine recycled aggregate, with the addition of 1% and 2% of 30 mm sisal fiber. Tests were performed on spreading, density, air content, mechanical strength, thermal conductivity, brick pullout, open porosity and capillary water absorption. The results showed that the recycled aggregate increased compressive strength, capillarity and porosity. The presence of fibers allowed large deformations before rupture, significantly improving mechanical strength and thermal conductivity.
- Substituição de agregados naturais por areias de leito fluidizado na produção de argamassas: uma abordagem para sustentabilidade na construção civilPublication . Khairallah, Larissa; Gonilho Pereira, Cristiana; Jasper, Catarina Marchi; Mello, AmandaThis study evaluates the viability of substituting natural aggregates with fluidized bed sands (FBS) in mortar production, aiming for sustainability in construction. The research evaluates the influence of partial and total substitution of natural fine aggregates with FBS through the characterization of the produced mortars and the aggregates composing them. Considering the scarcity and non-renewability of natural resources used in construction, this research emerges as a response to the need to rethink the use of these materials, seeking to minimize environmental impacts. The research methods involved characterization tests of FBS and the production of mortars with different compositions, including a reference mortar and three variations with partial and total substitution of natural aggregates with FBS. The results indicate that FBS has suitable physical characteristics to replace natural aggregates, although its addition affects the workability and mechanical properties of mortars. The analysis of the results suggests that the substitution of natural aggregates with FBS may lead to a decrease in mechanical strengths and an increase in open porosity and water absorption by capillarity. However, the results also show that the total substitution of natural aggregates with FBS may be viable, depending on the applications of the mortars.It is concluded that the use of FBS in mortar production represents a promising strategy to promote sustainability in construction, but further studies are needed to evaluate other parameters and confirm the conclusions of this initial study.
- Avaliação da substituição parcial de cimento Portland por cinza de queima de biomassa no desempenho de argamassasPublication . Jasper, Catarina Marchi; Gonilho Pereira, Cristiana; Betioli, Andrea Murillo; Waltrick, LarissaThe present work aims to evaluate the feasibility of using ashes from biomass combustion as a partial substitute for Portland cement in mortar compositions, assessing the changes in the fresh and hardened states. The study involves a comparison between a reference mortar made of Portland cement (CEM I 42.5) with a mix ratio of 1:3 and a water/binder (W/B) ratio of 0.6, and mortars with partial substitution of cement mass by ashes at substitution rates of 5, 10, 15, 20, and 25%, maintaining the W/B ratio constant. In the fresh state, the workability of the mortars was evaluated through the flow table test, density, and air content. In the hardened state, compressive and flexural tensile strengths, density and open porosity were assessed. It was found that the variation in properties, both in the fresh and hardened states, tends to be inversely proportional to the increase in the percentage of ash incorporation.
- Performance assessment of mortars produced with sand from fluidized bed of biomass burning plantsPublication . Gonilho Pereira, Cristiana; Deloroso, Júlia; Betioli, Andrea