Sustainable Solution for Reflective Crack Mitigation: Case Study of Texas State Highway 21

Abstract: Reflective cracking has been regarded as the major mode of distress in asphalt overlays that involves the propagation of pre-existing cracks that may be triggered by bending and shear stresses induced by repeated traffic loads, as well as by tensile stresses caused by thermal variations. There are numerous techniques available to mitigate the reflective cracking in asphalt overlays. Among them, the incorporation of geosynthetic interlayers during the rehabilitation of asphalt overlays have proven to be successful in mitigating reflective cracking. Additionally, geosynthetic interlayers that provide reinforcement function have also demonstrated to improve the structural capacity of the asphalt overlays. Such additional benefits from geosynthetic interlayers that provide reinforcement function not only mitigate reflective cracking, but also reduce the construction cost by reducing the asphalt overlay thickness. Reductions in asphalt overlay thicknesses would also reduce the carbon footprint associated with roadway rehabilitation, thus providing a sustainable solution. This study presents a comprehensive case history on the use of geosynthetic interlayers that provide reinforcement function to mitigate reflective cracks along the Texas State Highway (SH) 21 in Austin, TX. Specifically, case history involves the rehabilitation of an in-service roadway (SH21) built on an expansive subgrade soil that is subjected to heavy traffic conditions. The rehabilitation program involved repairing the pre-existing pavement, placing tack coat, installation of a polymeric based geosynthetic interlayer, and finally constructing 3-inch-thick asphalt overlay. The rehabilitated roadway was monitored frequently for over a period of 5 years. The field monitoring program demonstrated that the use of geosynthetic interlayer that provide reinforcement function could significantly help in mitigating reflective cracks, and reducing the associated roadway construction and maintenance costs, thereby providing a sustainable solution to mitigate reflective cracking in asphalt overlays.