Abstract Manager

Asphalt pavement lifecycles across Ontario have seen a reduction of more than 60% since the early 1980s. This deterioration of the network is largely due to an increase in the use of binder modifiers, reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS), re-refined engine oil bottoms (REOB), and a range of other lesser known additives. Additional stresses have arisen from increased traffic and climate change giving rise to less predictable weather with more frequent extreme temperatures in both winter and summer. In today's marketplace, where modification of asphalt binders is widespread, it has become critically important to do the best we can at specifying the correct asphalt binder composition and performance-based properties. Research at Queen's University, in collaboration with a large number of Canadian and United States user agencies, has shown that it is possible to turn the tide. Reasonable acceptance criteria for recovered asphalt binder properties that relate, in a mechanistic manner, to the major pavement distresses have been able to double and in some cases triple pavement lifecycles, bringing them back to historical levels that were commonplace in the 1970s and 1980s prior to the rise in binder modification. This presentation will provide an overview on the performance of over 50 pavement trial sections that supported the development of several enhanced binder specification tests. The double-edge-notched tension (DENT) and extended bending beam rheometer (EBBR) tests have now been formalized in AASHTO standards T-405 and T-406 and have been implemented for acceptance of the tank and recovered asphalt binder in hundreds of contracts around Ontario. By further tightening the acceptance criteria, and with a judicious choice of mix modification, it will be discussed how we might be able to achieve performance levels not yet seen before in cold continental climates.