Viscous properties and microstructure of recycled eva modified bitumen

This paper deals with the viscous properties of recycled-polymer modified bitumens (PMBs) in a wide range of temperatures. With this aim, two different penetration grade bitumens (60/70 and 150/200) and recycled EVA copolymer (EVAR) from agriculture films were processed in an open reactor using a four blade propeller. Polymer concentration ranged from 0 to 9 wt%. Viscous flow and DSC measurements, from 5 to 165 °C, and optical microscopy, at room temperature, were performed on the samples. From the experimental results obtained, we may conclude that the viscous properties of bitumen, at high temperature, are improved by adding recycled EVA copolymer in amounts that depend on bitumen penetration grade. Moreover, significant microstructural changes, related to the development of a polymer-rich phase, tend to occur in the bitumen as polymer concentration increased. These changes in microstructure have a significant influence on the flow behaviour of the binder and on its in-service performance. As a consequence, the use of recycled EVA in PMBs can be considered a suitable alternative from both environmental and economical points of view.