Análise da interação entre ligantes de mistura asfáltica com RAP, com e sem uso de agentes rejuvenescedores

Abstract

Recycling asphalt mixtures is a common practice adopted in road paving, aiming to reduce the waste of natural resources and production costs. To this end, Reclaimed Asphalt Pavement (RAP) is used, which is a material obtained from the milling process of old asphalt paving layers. However, the complex interaction between the virgin binder and the aged RAP binder is still a critical challenge to ensure the proper performance of recycled mixtures, which requires continuous research and development in the area. Basic and advanced tests are performed on binders to classify and determine their properties, serving to select the most suitable binder for the design of an asphalt mixture. The present work aims to analyze, through chemical, rheological and adhesive tests, the interaction between the binder extracted from the RAP and the new virgin binder, with and without the use of a rejuvenating agent. The study analyzes the portion of the binder within a mixture which is able to react. The mixtures were prepared with a final binder content containing different percentages of an aged RAP binder: 0, 15, 30 and 100% of the RAP binder (% by mass of the total binder mass). In addition, soybean oil and AESO (synthesized soybean oil product) were used as rejuvenating agents considering two different proportions, 5 and 10%, relative to the total binder mass. Penetration, softening point, rotational viscosity, Fourier Transform Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), SARA Fractionation, Frequency Sweep, Multiple Stress Creep Recovery, Linear Amplitude Sweep and Bitumen Bond Strength tests were performed. The viscoelastic behavior of the different binder combinations investigated was simulated using the 2S2P1D rheological model. The hardening of the RAP, caused by aging, negatively affects the essential properties of the binder. The physical characteristics of samples with an oil content of 10% do not meet the specifications of an asphalt cement 50/70 (classified by penetration). It was observed that the addition of oil and AESO in the binder mixes negatively affected the phenomenon of rutting, especially at high temperatures, even in samples with rejuvenating agent. The results of this study contribute to the advancement of knowledge about the behavior of recycled asphalt binders and may assist in improving the recycling processes and production of more sustainable asphalt mixtures.