Publicação
Production and characterization of diatomaceous earth-based geopolymers and geopolymeric mortars
| Resumo: | Since 1980, the world has faced an increase in the earth's average surface temperature due to the high release of carbon dioxide into the atmosphere. One of the main responsible for this CO2 release is the manufacture of Portland Cement, associated with a carbon dioxide emission of around 7% of the world's total emissions. In this way, there is a need to find alternatives to Portland cement to reduce these emissions. This work aims to contribute to this endeavor, proposing the application of a solid waste used as a wine filtration agent in the wine industry, diatomaceous earth, containing high amounts of silicon, to produce geopolymers and geopolymeric mortars. A geopolymer is an inorganic polymer produced with an aluminosilicate precursor reacted with an alkaline solution that has been studied as an alternative to cement in the composition of mortars and concretes. Diatomaceous earth and alumina were employed in this work as aluminosilicate sources for the geopolymer precursor, while sodium hydroxide and sodium silicate were used as the alkaline solution. The production process involved mixing all these raw materials of the geopolymers to create a fresh geopolymer, which was then combined with sand and water to form a mortar. In some instances, a specific amount of cement was also added to the binder along with the geopolymer. Subsequently, the samples underwent a 28-day curing process, with the initial four days placed in an oven at 40 ºC and then transferred to room temperature. Following production, the geopolymers were characterized using XRD, FTIR, SEM-EDS, and pore property analysis. On the other hand, the mortar samples underwent compressive and flexural strength tests and a flow test. The results revealed that the most favorable mortar sample, sample 2 (S2), utilized the top-performing geopolymer sample, Geopolymer 2 (GP2), as the geopolymeric binder. GP2 featured a NaOH concentration of 10 M, and a Si/Al ratio of 3,5. In the case of the S2 mortar, it consisted of 75% GP and 25% Portland Cement in the binder. This combination resulted in a higher proportion of geopolymer phase, consequently improving mechanical properties. |
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| Autores principais: | Murta, Júlia Ferreira |
| Assunto: | Geopolymers Spent diatomaceous earth Mortar Solid waste |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Since 1980, the world has faced an increase in the earth's average surface temperature due to the high release of carbon dioxide into the atmosphere. One of the main responsible for this CO2 release is the manufacture of Portland Cement, associated with a carbon dioxide emission of around 7% of the world's total emissions. In this way, there is a need to find alternatives to Portland cement to reduce these emissions. This work aims to contribute to this endeavor, proposing the application of a solid waste used as a wine filtration agent in the wine industry, diatomaceous earth, containing high amounts of silicon, to produce geopolymers and geopolymeric mortars. A geopolymer is an inorganic polymer produced with an aluminosilicate precursor reacted with an alkaline solution that has been studied as an alternative to cement in the composition of mortars and concretes. Diatomaceous earth and alumina were employed in this work as aluminosilicate sources for the geopolymer precursor, while sodium hydroxide and sodium silicate were used as the alkaline solution. The production process involved mixing all these raw materials of the geopolymers to create a fresh geopolymer, which was then combined with sand and water to form a mortar. In some instances, a specific amount of cement was also added to the binder along with the geopolymer. Subsequently, the samples underwent a 28-day curing process, with the initial four days placed in an oven at 40 ºC and then transferred to room temperature. Following production, the geopolymers were characterized using XRD, FTIR, SEM-EDS, and pore property analysis. On the other hand, the mortar samples underwent compressive and flexural strength tests and a flow test. The results revealed that the most favorable mortar sample, sample 2 (S2), utilized the top-performing geopolymer sample, Geopolymer 2 (GP2), as the geopolymeric binder. GP2 featured a NaOH concentration of 10 M, and a Si/Al ratio of 3,5. In the case of the S2 mortar, it consisted of 75% GP and 25% Portland Cement in the binder. This combination resulted in a higher proportion of geopolymer phase, consequently improving mechanical properties. |
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