Estudo da viabilidade da inserção do resíduo do cal de carbureto em pavimentação asfáltica

Abstract

This study had the general objective of evaluating the potential of using the carbide lime industrial residue in partial replacement to mineral aggregates conventionally used in asphalt paving. Thus, it was necessary to have a granulometric characterization of the carbide lime residue, which presented an average diameter of 0.0053 mm, which corresponds to a fine particle size. The analysis of the chemical composition of the carbide lime was performed using the x-ray fluorescence technique, in which we obtained the presence of the elements calcium (Ca) 96.038%, 3.195% silicon (Si), 1.126% aluminum (Al) and other elements, for example, Mg and Fe and the x-ray diffraction technique, used in the determination of crystalline phases. The main phase observed was Ca (OH)2, followed by a secondary phase such as CaCO3. The thermogravimetric analysis (TGA / dTG) of the carbide lime identified mass losses in characteristic ranges. In the range of 40.0 °C to 150.0 °C and 146.0 °C, three thermal events were observed, the first at 44.21 °C, the second at 74.16 °C and the third at 146.0 °C. These three thermal events present a loss of mass of 1,798%. In the range of 350, 0 °C to 550.0 °C, a thermal event was observed, with the maximum peak at 463.17 ° C. In this thermal event, a mass loss of 14.82% occurred. In the range of 550, 0 °C to 750.0 ° C, a thermal event was observed, with the maximum peak being 694.30 ° C. In this thermal event, a mass loss of 9.419% occurred. Exploratory calorimetry (DSC) analysis showed four endothermic peaks. The thermal event that showed a maximum peak at 696.71 ° C was due to the transformation of the Ca (OH)2, phase into CaO. The other three thermal events at 77.84 ° C, 149.41 ° C and 466.39 ° C, which are related to the vaporization of adsorbed water and the decomposition of CaCO3 to CaO. Three asphalt mixtures were developed using 3.0%, 4.0% and 5.0% of carbide lime residue, in order to evaluate its mechanical property, through the tensile strength - RT. Asphalt mixtures of 3.0% and 4.0%, showed better results compared to carbide lime (5%) and portland cement (3.0%). Thus, the use of carbide lime in asphalt compositions (3.0% and 4.0%), can be an alternative to the traditional filler type (Portland cement) for the production of asphalt mixtures.