A method to evaluate the tensile strength and ductility of asphalt binders using a thin confined film

It has become clear over the last few years with an increasing use of asphalt binder modifiers, additives and recycled materials that there is a need to develop methods and concomitant parameters that can evaluate the full tensile behaviour including nonlinearity and damage resistance of asphalt binders. This study presents a simple, repeatable test method to examine the tensile strength and ductility of asphalt binders using a poker-chip geometry. The poker-chip geometry has previously been used to induce a realistic stress state in asphalt binder similar to that exerted on asphalt binder confined between two aggregates. This study develops and presents a new simplified procedure for specimen fabrication and preparation using the poker-chip geometry. A set of nearly 100 asphalt binders including different aging conditions, different levels and types of modification, and recycled asphalt binders and contents were examined using the proposed approach. The results indicate that a ductility parameter obtained using the test is highly repeatable with an average coefficient of variation of 9%. In addition, the test was able to distinguish between different levels of modification and was sensitive to aging, recycled binder ratio and modifier type.v.