Hot Mix Asphalt (HMA) overlays are frequently used by highway engineers to rehabilitate deteriorated pavements. However, after repeated traffic loading and climatic changes, these overlays become ineffective due to the propagation of cracks from the existing pavement layer. This propagation of cracks from the existing pavement layer onto and through the new overlay is defined as reflective cracking. The main reason for the development of reflective cracks is the increase in tensile stress at the interface of the existing crack and the new hot mix asphalt overlay. Thus by increasing the tensile strength of the overlay, the propagation of reflective cracks can be mitigated. Geosynthetics have good tensile strength which can act as a stress reliever. Thus they can be used for reducing the propagation of reflective cracking in hot mix asphalt overlay. Many types of polymeric geosynthetics are available, which have high tensile strength. However, the overlays need to be replaced frequently due to wear and tear caused by the traffic loading. Some of the natural geosynthetics that can last safely for 5 to 6 years could have potential pavement overlay applications.
Various experimental and numerical studies have been conducted to study the performance of the interlayer system to mitigate reflective cracking. In this study, a methodology is developed to monitor the performance of interlayers over the long run using Finite Element Method. The delamination between the overlay and the old bituminous layer is studied by adopting the Cohesive Zone Model (CZM). The reflective crack growth is modelled with an advanced FEM technique called eXtended Finite Element Method (XFEM).