Impact of Construction Variability on Rutting Resistance of Hot-Mix Asphalt Mixtures (05-1772)
Gabriel Bazi, Lebanese American University
Peter E. Sebaaly, University of Nevada, Reno
Dean Weitzel, AMEC Environment and Infrastructure, Inc.
Mark Elicegui, Nevada Department of Transportation

The long term performance of hot mixed asphalt (HMA) pavements is significantly impacted by the properties of the HMA mixture. Regardless of how well the mix design and structural design have been prepared, the properties of the materials delivered to the job site, such as gradation, binder content, and the in-place compaction will ultimately control the behavior of the pavement under the combined action of traffic and environment. The job mix formula allows for certain tolerances in the HMA construction. This research evaluated the impact of these tolerances on the rutting resistance of the HMA mixture. The construction variability was studied for two Nevada aggregate sources along with two unmodified asphalt binders. Forty two mixes were prepared for each aggregate source and were tested for general strength using the resilient modulus (Mr) and for rutting resistance using the Asphalt Pavement Analyzer (APA). The construction variables included the gradation, the binder content, and the air-voids. All mixes were compared to the mix design mixture (MM22). Many HMA mixtures had significantly worse rutting resistance than the MM22 concluding that the contractor has to deliver a finished product meeting all specification limits.