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Neste trabalho apresenta-se um estudo laboratorial com base em pesquisas anteriormente desenvolvidas sobre ligantes geopoliméricos. O estudo desenvolvido visa perceber o efeito de adjuvantes na trabalhabilidade deste tipo de ligantes.
Foram preparadas pastas através da mistura de lamas da mina da Panasqueira com uma solução alcalina e com adição de alguns adjuvantes comerciais usados na industria do cimento Portland, como por exemplo policarboxilatos (de ultima geração) e naftalenos. As caracteristicas reologicas das pastas foram determinadas pelas medições num reómetro e também pelo uso do teste da flow table.
Os resultados indicam que os adjuvantes usados não funcionam nos sistemas activados alcalinamente da mesma maneira que funcionam no cimento Portland, embora tenha havido ligeiras melhorias na trabalhabilidade das pastas.
De maneira a melhorar a trabalhabilidade neste tipo de pastas foi também testado o efeito da temperatura no processo da mistura. O aumento da temperatura fez diminuir a viscosidade da solução alcalina, mas não melhorou a trabalhabilidade das misturas.
This work presents a laboratorial study based on previous researches about geopolymeric binders. The study is aimed at the knowledge of the effect of admixtures in the workability of this type of binders. In this study, an investigation related to the rheological behavior of alkali-activated pastes is described. Those pastes were prepared by mixing land mining waste from Panasqueira with an alkaline solution and adding some commercial chemical admixtures used in the Portland cement concrete fabrication, like polycarboxylates (latest generation) and naphthalene based. The paste rheological data were determined by rotational viscometer measurements as well as by the use of the flow table test. Results indicate that chemicals admixtures used do not work the same in the Portland cement systems than alkali-activated systems although there were slight improvements in the workability of the pastes. In order to improve the workability of this type of pastes was also tested the effect of temperature in the mixing process. Increasing temperature decreased the viscosity of alkaline solution but didn’t improve the workability of the paste.
This work presents a laboratorial study based on previous researches about geopolymeric binders. The study is aimed at the knowledge of the effect of admixtures in the workability of this type of binders. In this study, an investigation related to the rheological behavior of alkali-activated pastes is described. Those pastes were prepared by mixing land mining waste from Panasqueira with an alkaline solution and adding some commercial chemical admixtures used in the Portland cement concrete fabrication, like polycarboxylates (latest generation) and naphthalene based. The paste rheological data were determined by rotational viscometer measurements as well as by the use of the flow table test. Results indicate that chemicals admixtures used do not work the same in the Portland cement systems than alkali-activated systems although there were slight improvements in the workability of the pastes. In order to improve the workability of this type of pastes was also tested the effect of temperature in the mixing process. Increasing temperature decreased the viscosity of alkaline solution but didn’t improve the workability of the paste.
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Keywords
Ligantes geopoliméricos Ligantes geopoliméricos - Adjuvantes Cimento Portland - Geopolimerização Cimento Portland - Hidratação Geopolímeros - Resíduos de minas - Adjuvantes