Evaluation of cracking resistance potential of geosynthetic reinforced asphalt overlays using direct tensile strength test

Abstract

The study aims at evaluation of cracking resistance potential of geosynthetic reinforced two-layered asphalt specimens under direct tensile strength test (DTT), conditioned at different temperatures (20 °C, 30 °C and 40 °C). Apart from determining the tensile stiffness of the asphalt specimens, the DTT is also capable of evaluating the cracking resistance potential through estimating the energy dissipated during cracking. The potential to resist reflection cracking may be improved with the inclusion of geosynthetic-interlayer. To understand the crack propagation patterns and to quantify the resulting strain fields, digital image correlation (DIC) technique was employed. The geosynthetic-interlayers used in the current study consist of a glass-grid composite (GGC), a bi-axial polyester grid coated with polymer modified binder (PE), a biaxial polypropylene grid (PP) and a woven geo-jute mat (GJ).Results indicate that all the specimens conditioned at a temperature of 20 °C have shown better resistance to the cracking than the specimens conditioned at 40 °C. The specimens with GGC interlayer were effective in controlling the cracks as they could mobilize high tensile strength at a low strain value. The digital image analysis was instrumental in quantifying the tensile strains developed in the pavement layers. It was noticed that the control specimens have developed a tensile (vertical) strain of 6.85% at 20 °C against 2–4% in the specimens with geosynthetic-interlayers.