Shear Bonding Performance of Reinforced Asphalt Pavements by Using Polyester Grids

The conventional method for rehabilitation of cracked asphalt pavements is the installation of new asphalt layers. This resurfacing is often not an effective solution, as the existing cracks in the old asphalt layers can propagate rapidly to the top of the new overlay. In order to delay the development of reflective cracking, asphalt reinforcement grids have been used all over the world for many years, showing outstanding results. The grid changes the response of the pavement to loading, increasing the resistance of the asphalt overlay to high tensile stresses and distributing them over a larger area. Thereby the peak shear stresses are reduced at the edges of the existing cracks and thus the crack propagation can be retarded. Nevertheless, the performance of reinforced pavements depends strongly on the adhesion between the interlayer and the asphalt courses. The purpose of this paper is to report shear bonding performance verified in laboratory and in the practice by using a high modulus polyester grid as asphalt reinforcement. Shear bonding tests according to Leutner method have been carried out for different core samples, produced in laboratory as well extracted from test sections or from pavements in operation. The results show that a high bond strength between the asphalt layers can be reached when using an asphalt reinforcement grid, inclusive considering the long-term performance. In this way, the condition of repaired roads can be maintained at high levels over extended periods of time.