Selection and Evaluation of Performance-graded Asphalt Binders for Virginia

About the report:

This study recommended and evaluated performance-graded (PG) binders for use in hot-mix asphalt in Virginia. Ten conventional viscosity-graded asphalt cements, representing the asphalt typically available in Virginia, were graded under the PG system to develop a cross-reference with the new system. Based on the past performance of the viscosity-graded asphalt and the PG binder testing, PG 64-22 binder was selected as the base grade of asphalt for Virginia. Laboratory studies were performed with the Georgia loaded-wheel tester and asphalt pavement analyzer to evaluate the use of increasing the high-temperature binder grade for heavy or slow-moving traffic. Based on the success of these studies and field trial sections, two new mix types, SM-2D and SM-2E, both 50-blow Marshall mixes with PG 70-22 and PG 76-22 binder, respectively, were developed. A lower laboratory compaction effort will increase the asphalt content for durability, and the stiffer binder will prevent rutting. A large database of field rut depth data was developed for Virginia Department of Transportation surface mixes with the asphalt pavement analyzer. The data were used to estimate maximum rut depth criteria for quality assurance and evaluation of future asphalt mix designs, binders, and stabilizers.

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