Interlayer Shear Performance of Geocomposites Applied Under WMA Layers

Nowadays, the use of geocomposites at the interface of asphalt layers is extensively adopted to improve overall pavement performance (i.e. rutting, fatigue and reflective cracking) as well as to ensure waterproofing properties. However, the presence of an interlayer reinforcement causes de-bonding effects that can penalize the pavement integrity and serviceability. Given this background, this study focuses on the effectiveness of pavement rehabilitation with reinforcement systems by evaluating the interlayer shear performance of different geocomposites, applied under warm mix asphalt (WMA) layers. To this end, shear tests by means of Leutner and Ancona Shear Testing Research and Analysis (ASTRA) equipment were carried out on double-layered reinforced samples prepared in the laboratory. Experimental results showed that a proper geocomposite optimization in terms of inner reinforcement type, geomembrane compound and underside finish can significantly enhance the interlayer shear strength (ISS) of asphalt systems produced with reduced temperature (i.e. WMA). All the ISS results were also compared with the Italian technical specification requirements to verify the applicability of geocomposites in real scale.