Workability and Performance of Polymer-modified Asphalt Aggregate Mixtures in Cold Regions

Abstract

Polymer-modified asphalts have been used in cold regions for about 15 years to address problems with rutting, cracking and premature aging. However, due to the cold climate and remote locations construction problems are sometimes encountered. This paper deals with workability of polymer-modified mixes while assuring that the desired pavement performance is achieved.

The construction problems arise with possible poor compatibility of the base asphalt and the polymer, the storage stability of the asphalt–polymer mixture and cold construction temperatures. These properties were tested for several polymer-modified asphalt combinations. A set of products that were compatible, storage stable and had improved temperature susceptibility were selected and further tested in asphalt-aggregate mixtures. A Georgia Wheel rutting test and the Thermal Stress Restrained Specimen Test were performed. A questionnaire study was also conducted to collect experiences and specifications in cold regions.

Tests indicate that polymer-modified asphalts should always be the end result of an extensive product development program. The polymer modification improved the performance of all base asphalts in certain polymer–asphalt combinations. However, some otherwise acceptable binders smoked excessively when the temperature was elevated to the recommended mixing temperature. This issue warrants further investigation.

Keywords:

• Low-temperature cracking
• Rutting
• Cold region
• Polymers
• Specifications

Acknowledgements

The authors are grateful to the U.S. Department of Transportation Federal Highway Administration for providing funding and technical support for the project. The authors would also like to thank the following persons who contributed their valuable time for this project: Scott Gartin, David Sterley, Aaron Weston, Billy Connor, Denny Wohlgemuth, Maureen Lee, Lynn Aleshire, Matt Mann and Sean Bakinsky.

Notes

^†[email protected]

^‡[email protected]

^¶[email protected]

^§[email protected]