Reflective cracking in asphalt overlays reinforced with geotextiles

Abstract

The use of overlays in pavement rehabilitation is one of the most common techniques in pavement management systems. It can be used when a pavement structure is still in adequate structural condition and the observable distresses can be corrected, ensuring that pavement condition can be maintained for an additional service period. The main issue related to the performance of this technique is the reflection of existing cracks. In order to delay the propagation process, interlayer systems can be used (e.g. geosynthetics). Although research on this area has been conducted previously, it is still necessary to better understand the mechanical behavior of the hybrid system to improve the efficiency of its performance. The following paper shows the results obtained from the measurements and modeling based on core samples extracted from an experimental test section built using geotextiles as an interlayer system prior to overlaying. The samples were evaluated in the laboratory by means of the Overlay Tester. The fracture mechanics and viscoelasticity properties were determined from Indirect Traction Tests, in order to define the Cohesive Zone Model (damage), and Dynamic Modulus Tests (viscoelastic Prony Series parameters). The results helped describe the mechanical behavior associated with the reduction in the reflective cracking process when geotextile materials are used as interlayer system: (i) increase in fatigue life (up to 260 %, due to the energy dissipation capabilities of the material), and (ii) crack propagation trend (which generally follows geotextile-asphalt layer interface, and depends on the amount of binder content, testing conditions and existing material).