O uso de polietileno de alta densidade como modificador do cimento asfáltico de petróleo

Abstract

The performance of a road pavement is strongly dependent on the properties of the petroleum asphalt cement (PAC) used. To achieve superior mechanical properties, several studies propose its modification, and recently using plastic waste, as a way to contribute to sustainability. This work aims to evaluate the effect of adding high density polyethylene (HDPE) in pellet format to conventional asphalt binder. The contents of 1, 3 and 5% of HDPE were evaluated in relation to the mass of CAP, incorporated by wet way. Penetration, Softening Point and Elastic Recovery tests were performed, in addition to short-term aging in RTFOT (Rolling Thin Film Oven Test). For rheological characterization, it was verified the Rotational Viscosity using Brookfield viscometer, the high PG and the master curves of Dynamic Modulus and Phase Angle, using the Dynamic Shear Rheometer (DSR). The 2S2P1D modeling was used in data analysis. Damage characterization was performed by MSCR (Multiple Stress Creep Recovery) and LAS (Linear Amplitude Sweep) tests. Finally, the phase separation test was carried out to verify storage stability. The modification of CAP 50/70 produced its stiffening, and the Elastic Recovery test proved to be inadequate for this type of modified binder. A considerable increase in the viscosity found was observed, signaling the need for higher temperatures to obtain the appropriate workability. The application of the time-temperature superposition principle and the 2S2P1D modeling proved to be effective in the data analysis, although some discontinuities were observed in the curves with the highest contents. The analysis of the master curves indicated higher values of dynamic shear modulus and lower values of phase angle, especially in the contents of 3 and 5% of HDPE. There was also an increase of the high PG, expanding the application range of the modified binder. The highest contents of HDPE also showed better results with regard to the permanent deformation test (MSCR). The Binder Fatigue Factor and C versus N criteria indicated that the higher contents of HDPE improve the fatigue behavior, contrary to what the crack opening rate criterion suggested. The mixing protocol caused significant aging and still needs to be optimized. Finally, the analysis of the samples showed excessive phase separation, reinforcing the need for constant agitation of the asphalt tanks. Thus, understanding the interaction of plastic with the asphalt matrix still needs to be studied, but it has shown a proven feasibility for use in paving.