Arizona, Where the Rubber Meets the Rubber, 14 Years of Success Using Ground Tire Rubber in Pavements

摘要

The Arizona Department of Transportation (ADOT) has used crumb rubber from ground tires since the late 1960s to primarily reduce reflective cracking in pavement overlays, and to provide a smooth riding, durable, and low maintenance surface. In 1988, the ADOT began to incorporate crumb rubber mixed with hot asphalt, commonly referred to as asphalt rubber (AR) as a binder in hot-mix asphalt (HMA) pavements. Typically, these mixes are composed of an open-graded or gap-graded aggregate mixture from 12.5 mm (1/2 in.) to 25 mm (1 in.) or 25 mm (1 in.) to 50 mm (2 in.) in thickness, respectively. Open-graded mixes generally contain 9-10% AR binder, whereas the gap-graded contains generally 7.5-8.5% AR binder. Approximately 30-40 lb of ground tire rubber is used per ton of hot mix. To date, field performance has been very good and over 2500 mi of pavements with AR have been built. As an extra benefit, the ground tire rubber from over 10 million tires in Arizona has been recycled since 1988, which means there are no waste tire piles in the state of Arizona.