Influence of recycled asphalt shingles on fatigue properties of asphalt pavements

As the use of Recycled Asphalt Shingles (RAS) in asphalt pavements gains wider acceptance, questions remain about the effects of RAS on the fatigue performance of asphalt pavements. To compare the fatigue performance of RAS pavements to non-RAS pavements, pavement mixtures may be evaluated with accelerated laboratory fatigue tests. For this paper, repeated flexural beam performance testing was conducted to study the load-associated fatigue characteristics of several types of RAS mixtures. The RAS mixtures were field produced samples of pavements from several states designed with different RAS sources, percentages, specifications, and mix types. Repeated flexural loading on the four-point bending beam apparatus was conducted on samples to compare how the different RAS variables affect fatigue cracking. The test results indicate that low percentages of RAS can enhance the fatigue characteristics of asphalt pavements with some construction specifications being more beneficial than others.