Argamassas produzidas com resíduo de scheelita: propriedades mecânicas, durabilidade e microestrutura.

Abstract

The generation of waste in the industrial sector is a problem that has been followed by the economic growth of the sector. Presenting solutions and alternatives that minimize the environmental impact caused by the incorrect way of disposal of these wastes has been increasingly a concern of the producers. Through research on non-conventional materials, the construction industry has been able to absorb this demand for sustainable alternatives. This research had as objective to analyze the mechanical properties and durability of coating mortar produced with the incorporation of residues from the Scheelite beneficiation industry. In order to identify the potentials for the use of alternative raw materials, this residue was characterized by the following techniques: granulometry, specific and unit mass, X-ray diffraction, thermogravimetry, X-ray fluorescence chemical analysis and spectrometry by absorption. After the characterization tests, compositions were defined and, with the best results of mechanical performance of these compositions, were determined the following properties: water absorption, traction adhesion potential, durability by wet and dry cycles method. The alkali-aggregate reaction was investigated by the bar expansion test by the accelerated method and through analysis of images obtained by scanning electron microscopy (SEM) and by dispersive energy spectroscopy (EDS). In the results of the bar expansion test, expansions were identified that indicated residue reactivity. The images obtained by MEV and EDS did not reveal the presence of formation of any deleterious gel, but they showed the occurrence of cracks that corroborate with the results obtained in the expansion test. The absence of the gel suggests an alkali-carbonate reaction due to the strong presence of calcite in the samples. Thus, it was possible to conclude that the residue can presents reactivity with the cement components and can be used as a substitute for normal sand in the production of coating mortar, provided that the cement used in the mortar can inhibit these reactions.