Blocos álcali-ativados de resíduos industriais compactados

Abstract

Among the existing construction techniques, the use of the compacted earth block stands out because it is a product that dispenses the burning phase, besides the benefits as thermal and acoustic performance in accordance with the current norms. The blocks have the capacity to incorporate industrial waste and can be chemically stabilized by alkaline activation. Alkaline activation consists of obtaining a binder from aluminosilicate materials in highly alkaline solutions. Therefore, two residues generated in large volume by industrial processes, ashes produced by thermoelectric from eucalyptus biomass and iron ore tailings, were used to make alkaline activated compacted blocks. As a contribution to the destination of these materials, the objective of this work was to develop blocks using these residues, respecting the normative requirements. The ash and the tailings were characterized by scanning electron microscopy, X-ray fluorescence spectrometry, X-ray diffraction, differential and thermogravimetric analysis, fire loss and laser diffraction granulometry. Three composition ratios were proposed in the activator (SiO2 / Na2O = 1.00, 1.55 and 1.85) and three different ash and tail ratio (30-70, 50-50 and 70-30). These compositions were characterized by compressive strength and water absorption at 7 and 28 days. The trace with the ash/reject ratio 70/30 and SiO2/ Na2O 1.55 presented the best performance and was therefore selected for confection of the blocks. The blocks were submitted to tests of resistance to compression, water absorption, leaching and expansibility and showed higher results than the norms parameters in all the tests performed.