Reologia e calor de hidratação de pastas de cimento classe G contendo sílica ativa recoberta de nanoestruturas de carbono obtidas a partir de embalagens pet pós-consumo

Abstract

During the drilling stages of an oil well, cementing operations are carried out. The quality of this cementation is very important, since it directly affects the service life of the oil well, promoting not only hydraulic insulation as well as ensuring its mechanical stability. Carbon nanomaterials, such as graphene, have attracted scientific interest due to their remarkable electrical, mechanical, and thermal properties. Graphene is a material with high potential for applications in different areas of knowledge: for example in reinforcing cementitious matrices. The knowledge about the changes that the incorporation of these nanomaterials can imply in the properties of cementitious pastes has great scientific relevance, especially about the impacts on the rheological properties of the paste after mixing and the temperature variation generated by the heat of hydration. In this work, the behavior of Class G cement pastes produced with silica fume covered with carbon nanostructures was analyzed. The nanostructured silica fume had PET as a carbon precursor for graphene. The carbon material contents adopted were 0.025%, 0.05% and 0.1% of the total mass of the cementitious materials. Rheology in the fresh state, using a Kantro mini-slump and a rotational rheometry, as well as the heat of hydration, were evaluated. Rheological data were adjusted by the Bingham model. Regarding the tests on the paste in the fresh state, the presence of nanostructured silica fume did not alter the rheological behavior of the cement pastes, nor did it significantly change their heat of hydration.