ESTUDO DE CINZAS VOLANTES DE ALTA TEMPERATURA E DE LEITO FLUIDIZADO VISANDO A PRODUÇÃO DE MATERIAIS SUSTENTÁVEIS A BASE DE CIMENTO

Abstract

In cement production, replacing cement with fly ash is one way of reducing manufacturing cost and CO2 emissions simultaneously. Different combustion processes generate ashes with different characteristics. The objective of this work was to verify the effects of the partial replacement of high temperature fly ash (HTFA) with low reactivity, by fluidized bed fly ash (FBCA) on cement-based matrices. The performance of these ashes was compared in pastes and mortars by means of four proportions of cementitious material: reference only with Portland cement CPI; bulk replacement of 43% of the cement by HTFA; and mass replacement of 9 and 13% of HTFA by FBCA. Pastes were evaluated for the heat of hydration, rheology and chemical retraction, and mortar, as for mass density and mechanical resistance to axial compression and flexural tensile strength after 2, 7, 21 and 28 days of cure. When comparing the results, it was possible to observe that the retraction increased, and the workability decreased in the folders with FBCA. Likewise, the greatest strengths were presented by mortars with FBCA. Thus, partial replacement of HTFA by FBCA in cementbased matrices is promising.