Desenvolvimento de ligantes asfálticos modificado com lignina como aditivo antienvelhecimento

• Ano de defesa: 2017
• Autor(a) principal: Kenia Barros Batista
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia Mecânica; Engenharia mecânica; Intemperismo; Lignina
• Link de acesso: http://hdl.handle.net/1843/BUOS-AVTMCJ

Asphalt aging is an important problem, and research on anti-aging additives has been carried out to mitigate degradation by the effect of solar radiation. Lignin was selected as an anti-aging additive because of its antioxidant power. The properties of the binders and aggregates determine the performance of the asphalt pavement. This work aims to evaluate the effect of solar radiation, rainfall and temperature on the aging of modified asphalt binders with different lignin contents through weathering tests. The tests were performed using a weathering chamber with a xenon radiation cycle, moisture and temperature to simulate the in situ aging of the asphalt binder. To characterize the modified binder, Brookfield viscosity, softening point and penetration tests were performed. The samples were aged in a xenon radiation weathering chamber, and using the Rolling Thin Film Oven Test (RTFOT), and Pressure Aging Vessel (PAV). The techniques of thermal analysis, rheological analysis with dynamic shear rheometer (DSR) and bending beam rheometer (BBR), and the Fourier transform infrared spectroscopy (FTIR) technique were used to evaluate the asphalt degradation. In addition, the Marshall test was used to determine the tensile strength and modulus of resilience of the asphalt mixtures made with the lignin modified binders. Lignin increased the Brookfield viscosity of the binders. The lignin-modified asphaltic binder showed a lower carbonyl content and therefore a higher aging resistance than the conventional binder except for the binder with 4 wt.% lignin content after 200 hours of weathering test. The modified binder sample with 4% lignin content increased its thermal stability after the Rolling Thin Film Oven Test (RTFOT). Rheological analysis using the dynamic shear rheometer (DSR) showed that as the lignin content in the binder increased, the sample became stiffer. Lignin significantly improved the asphalt's resistance to thermal cracking at temperatures up to -12 ° C. For the asphalt mix tests, the results showed that there was practically no change in Marshall's stability and creep as well as in tensile strength, but in the test of the resiliency modulus, the samples modified with lignin, especially with 6 wt.% content, showed greater resistance to plastic deformation.