4 - Rheological performance of soft and rigid waste plastic-modified bitumen and mastics

Abstract

Bitumen is a thermoplastic material that shows viscoelastic properties by changing the operating conditions. It is standard practice to study the viscoelastic properties of an asphalt material at various stress and strain levels, where the behavior of the material is still linear, that is, where the relationship between stress and strain is influenced only by temperature and loading time and not by the magnitude of the stress or strain. To evaluate the performance of the new blends when the waste plastics are added to binder some studies focused on rheological analysis. In this study, the rheological performance of asphalt mastics containing waste plastics as filler (PF) in substitution of traditional limestone filler (LF) was investigated. The main objective of the research was to blend neat bitumen 50/70 and waste plastics in the right proportion to exceed the performance of traditional mastics composed by LF and at the same time meeting the performance of commercial PmB 10/40-70 modified bitumen. This study was focused on the investigation of performance properties of waste PF when it is introduced into asphalt mastics with a double function: first, as a modifier of bitumen and, second, as filler in substitution to traditional limestone. The waste plastics in the exam were of various types, such as Propylene (PP), Polyethylene-terephthalate (PET), High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE).