Selection and Evaluation of Performance-Graded Asphalt Binders for Virginia

摘要

This study recommended performance-graded (PG) binders to be used in hot-mix211u001easphalt in Virginia. Ten conventional viscosity-graded asphalt cements, 211u001erepresenting the asphalt typically available in Virginia, were graded under the 211u001ePG system to develop a cross-reference with the new system. Based on the past 211u001eperformance of the viscosity-graded asphalt and the PG binder testing, PG 64-22 211u001ewas selected as the base grade of asphalt for Virginia. Laboratory studies were 211u001eperformed with the Georgia loaded-wheel tester and asphalt pavement analyzer to 211u001eevaluate the practice of increasing the high-temperature binder grade for heavy 211u001eor slow-moving traffic. Based on the success of these studies and field trial 211u001esections, two now mix types, SM-2D and SM-2E, both 50-blow Marshall mixes using 211u001ePG 70-22 and PG 76-22 binders, relatively, were developed. The lower laboratory 211u001ecompaction effort will increase the asphalt content for durability, and the 211u001estiffer binder will prevent rutting. A large database of field rut-depth data was 211u001edeveloped for Virginia Department of Transportation surface mixes with the 211u001easphalt pavement analyzer. The data were used to estimate maximum rut-depth 211u001ecriteria for quality assurance testing and the evaluation of future asphalt 211u001epavement analyzer. The data were used to estimate maximum rut-depth criteria for 211u001equality assurance testing and the evaluation of future asphalt mix designs, 211u001ebinders, and stabilizers.