Evaluation of reclaimed polyethylene modified asphalt concrete mixtures

The present work is concerned with the use of reclaimed polyethylene (PE) obtained from low-density polyethylene (LDPE) carry bags, a locally available low-cost waste material collected from garbage, for modification of (80/100)-grade asphalt. Test samples were compacted using gyratory testing machine at various asphalt contents. Based on tensile strength ratio and retained stability test results, it was observed that PE-modified asphalt mixtures showed improved resistance to moisture induced damage. Beam fatigue tests were carried out on asphalt mixtures to evaluate engineering properties like fatigue life, stiffness modulus, dissipated energy and phase angle at 20, 30 and 40°C under constant strain-mode condition. At all tested temperatures, the flexural stiffness of the PE-modified mixtures were found to be comparatively higher than the conventional mixtures, whereas the dissipated energy and phase angle of the PE-modified asphalt mixtures were found to be comparatively lower than conventional mixtures. Fatigue life of the PE-modified mixtures increased by 2.5 times when compared to conventional mixtures. Charts have been developed for the design of flexible pavements using PE-modified asphalt mixtures. It was found that the thickness of the PE-modified asphalt mixture for a given traffic is substantially lower than the conventional mixture for a given practical thickness of granular bases. Copyright @ Chinese Society of Pavement Engineering.