Field Validation on the Use of Poker-Chip Test to Predict Cracking in Flexible Pavements

Cracking in flexible pavements is one of the most prevalent forms of distress. Two types of cracking ubiquitous to most regions are fatigue or alligator cracking, and thermal or low-temperature cracking. Cracking characteristics of a flexible pavement depend on a combination of factors that include the structural design of the pavement, asphalt mixture properties, component material properties, and construction quality. The cracking resistance of asphalt mixtures used in flexible pavements may be improved by use of asphalt binders with properties that are suitable to the application. Asphalt binder relies on its stiffness, tensile strength, ductility, and ability to relax to resist cracking due to repeated loading or changes in temperature. In current performance grade specifications of asphalt binders, cracking resistance is primarily characterized by asphalt rheology. Over the years, several researchers have considered this to be a gap. Several studies have been conducted to close this gap by considering various properties including strength and ductility. This study focuses on ductility of asphalt binders as measured by the poker-chip test to resist cracking. Field performance data measured on several pavement sections in Texas were compared with ductility of asphalt binders recovered from field cores. This study finds the poker-chip test to be a promising means of measuring ductility as well as characterizing ability of asphalt binders to resist fatigue and thermal cracking.