Avaliação de misturas asfálticas com Pavimento Asfáltico Recuperado (RAP)

Abstract

The incorporation of Reclaimed Asphalt Pavement (RAP) into hot-mix asphalt mixtures constitutes a technical, economic, and environmental alternative of growing interest in the road infrastructure sector. This research uniquely compared the mechanical behavior of asphalt mixtures produced in a plant with different RAP contents (0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 40%), from which laboratory specimens were molded and an experimental field section was constructed. One year after construction, pavement samples were collected at proportions of 5%, 10%, 15%, 20%, 25%, 30%, and 35% RAP, and Resilient Modulus (RM) and Indirect Tensile Strength (ITS) tests were performed, aiming to compare the performance of laboratory-molded specimens with that of samples extracted after one year of traffic and climatic exposure. Material characterization was carried out through granulometric analyses, Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), and Fourier Transform Infrared Spectroscopy (FTIR) of the binder recovered from the RAP. The mixtures were produced in a continuous-flow plant, with gradation conforming to Grading Range C-12.5 according to DNIT ES 031/2006 and were designed using the Marshall method. Laboratory results showed an increasing trend in RM (5,703.6 to 8,467.5 MPa) and ITS (1.635 to 2.042 MPa) with increasing RAP content, attributed to the stiffening effect promoted by the residual aged binder from the milled material. In the field-extracted specimens, RM values ranged from 4,743.3 MPa to 5,515.0 MPa, and ITS values ranged from 1.105 MPa to 1.575 MPa, with average reductions of approximately 24% and 22% compared to laboratory samples, respectively. All ITS values met the minimum limit of 0.65 MPa established by DNIT ES 031/2006. It is concluded that the incorporation of RAP into hot recycled asphalt mixtures is technically and environmentally feasible, providing increases in RM and ITS values without compromising the mechanical performance of the compositions.