Abstract
Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 ºC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 ºC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.
Highlights
RESUMEN: Evaluación del comportamiento a la fatiga de másticos bituminosos reforzados con poliolefinas a través de una metodología basada en energía disipada
Most of the studies conducted on fatigue damage in bituminous mastics are based on the so-called dissipated energy approach, which has been applied to other materials like polymers, metals and composites (1)
Strain-controlled tests demonstrated that bitumen modification with 4 wt.% LDPE enhances the mastic fatigue resistance if compared to an unmodified bitumen with equivalent hardness
Summary
RESUMEN: Evaluación del comportamiento a la fatiga de másticos bituminosos reforzados con poliolefinas a través de una metodología basada en energía disipada. Most of the studies conducted on fatigue damage in bituminous mastics are based on the so-called dissipated energy approach, which has been applied to other materials like polymers, metals and composites (1). These studies are frequently carried out in stress-controlled mode (6,7) for mixtures used in thick asphalt concrete layer and strain-controlled mode (8) for materials that are used in thin asphalt concrete layers. Even though not mentioned, most of the published works on this field makes use of Equation [2] even if nonlinear conditions are tested (3) assuming that the first harmonic corresponding to the output signal has a much larger contribution if compared to the remaining odd harmonics (10)
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