Avaliação da influência de adições minerais no comportamento reológico de pastas cimentícias utilizando o mini cone

Abstract

The construction industry has been looking for the use of sustainable solutions, one of which is the incorporation of waste as building materials. For this, studies have been developed to analyze the feasibility of incorporating these residues into pastes and concrete, as these insertions change the properties of materials both in hardened and fresh state. The analysis of materials such as pastes or concretes in their fresh state is directly linked to the study of a simulation of the demands that these may suffer during mixing, transport and application. The constituent materials and the water/binder ratio play a fundamental role in the properties of the pulps. Characteristics such as binder fineness, particle shape and mineralogical origin can directly affect its workability. To understand the rheological behavior of cementitious pastes in the fresh state, several techniques can be used such as flux and oscillation rheometry, the minicone scattering method, flow through the Marsh funnel, the Squeeze flow method and the Vane test. In this research, the rheological behavior of different cementitious pastes prepared with Portland cement CP V-ARI and addition of metakaolin (MK) and addition of ground ceramic brick waste (GBW) was studied. The pastes were analyzed for different water/binder ratios. Various combinations of pastes containing Portland cement with MK or GCW were studied with replacement of 0, 10 and 20% of these additions in relation to the total mass of materials and a water-binder ratio of 0.5 and 0.6. The pastes were analyzed both manually and mechanically mixed. The results showed that the mixtures containing the additions had a lower spread than the pastes containing only Portland cement and water. Pastes containing GCW had greater spread and caused a decrease in the initial yield stress when compared to the use of MK, which can contribute to a mixture that is easier to handle, that is, less viscous, and it was also found that in all mechanical mixing process was more efficient than the manual process.