Aplicação de óleo de motor residual como agente rejuvenescedor em misturas asfálticas com RAP

Abstract

The reuse of reclaimed asphalt pavement (RAP) in recycled mixtures is constrained by the aging of the binder it carries, a condition that has motivated the use of rejuvenating agents. Among them, waste engine oil (WEO) combines wide availability, low cost and a circular-economy appeal, yet most available investigations were carried out abroad and with high RAP contents. This exploratory study assessed the influence of WEO dosage on the volumetric parameters and the mechanical behavior of recycled asphalt mixtures with a moderate RAP content, set at 10%, using materials of regional origin. Four mixes were defined, one reference without rejuvenator and three with WEO at 1%, 2% and 3% relative to the total binder, keeping the total binder content constant in order to isolate the effect of the rejuvenator. The constituent materials, the 50/70 penetration-grade asphalt cement, the RAP and the aggregates, were characterized according to the applicable standards, and the aggregate blend was fitted to band C-12.5 of DNIT 031/2024. Specimens were molded by the Marshall method, with 75 blows per face, and subjected to Marshall stability and flow tests and to the indirect tensile strength test by diametral compression, complemented by volumetric analysis. The research adopts DNIT 031/2024 and DNIT 033/2021 as normative references. All mixes met the mechanical requirements, with stability between 1191.82 kgf and 728.09 kgf and indirect tensile strength between 1.524 MPa and 0.845 MPa, above the normative minima; the volumetric criteria, however, were met only by the reference mix, since the addition of WEO raised the air voids above 5% and reduced the voids filled with asphalt below 65%. It is concluded that, at the moderate RAP content adopted, WEO acted predominantly as a binder diluent, and the methodology provides a basis for future investigations at higher RAP contents.