Performance-based characterization of recycled polymer modified asphalt mixture

Abstract

Due to the introduction of secondary materials, the asphalt mixtures to be designed and tested in our laboratories are constantly becoming much more complex than traditional asphalt mixtures making difficult to use conventional laboratory procedure and/or predict expected results. This study proposes a comprehensive characterization of asphalt mixture modified with recycled polymer compound by using both wet and dry process proposing adjustments to laboratory mixing and sample compaction procedure. Accordingly, three AC20 Hot Asphalt Mixture (HMA) were designed and their conventional and performance related properties were assessed by looking at a) Indirect Tensile test (ITS) a) moisture damage by Indirect Tensile strength Ratio (ITSR) test; b) cracking by fatigue and Semi-Circular Bending tests and c) rutting both considering Stiffness Modulus (ITSM) and susceptibility to deform by Wheel Tracker. The results demonstrate that the addition of recycled polymer compounds using dry process might lead to the need to adaptation of the laboratory mixing procedure and the proposed mixing and compaction procedures allowed to engineer a superior recycled polymer modified asphalt mixture manufactured through the dry process, since an increment of mechanical related properties, than traditional asphalt solutions, was exhibited by these modified asphalt mixtures in terms of ITS (+32%), ITSM (11% at 10 degrees C, +18% at 20 degrees C, and +34% at 40 degrees C), rutting resistance (rut depth of 1.86 mm vs 1.92 mm) and fatigue life.