Viabilidade de misturas asfálticas recicladas com ácido graxo da borra do óleo de soja.

Abstract

The growing demand for raw materials and energy, and the increase in population justify the use of the circular economy, which seeks to reduce environmental impact and economic gains. The use of recycled asphalt pavement (Reclaimed Asphalt Pavement - RAP) in the production of hot asphalt mixes (Hot Asphalt Mixtures - HMA) has been used in paving due to the scarcity of virgin materials. However, the use of high percentages of RAP is conditioned to its susceptibility to failure at low temperatures and to fatigue damage. The addition of rejuvenating agents can partially restore the aged properties of the recovered binder. Hence, researching industrial waste and by-products are necessary to bring solutions that foster the tendency to work from a circular economy perspective, which is based on the economy and the circulation of waste and by-products between different sectors, including road engineering. This work evaluated the use of soybean oil sludge fatty acid (SSFA) as a rejuvenating agent for recycled asphalt mixtures, as well as analyzed the technical, economic and environmental feasibility regarding the circularity of these materials. In the first step, the characterization of the binder was carried out through penetration tests, softening point, rotational viscosity, performance grade (PG); before and after short-term aging (RTFO), and multiple stress creep recovery (MSCR). The second stage corresponded to the mechanical analysis of the mixtures through tests of tensile strength, susceptibility to moisture, resilience modulus, dynamic modulus, fatigue, and permanent deformation; in the third stage an analysis of circularity was carried out and in the fourth stage a comparative study was carried out analyzing the cost of production of these. The results showed a rejuvenating effect of SSFA and it was used as a modifier of recycled asphalt mixtures with 40% RAP in levels of 0, 3 and 5%. The addition of RAP improved the resistance to permanent deformation and the SSFA improved the fatigue performance of the recycled mixtures at the tested grades. The recycled asphalt mixtures presented the highest circularity indexes. The incorporation of accruals increased as accrued SSFA costs did not increase the increase. Therefore, the recycled mixes were more technically, environmentally and economically viable than the traditional asphalt mix, especially the mix with 3% SSFA.