Optimizing Asphalt Pavement Performance for Climate Zones Within Washington State

Abstract

Asphalt pavement performance in Washington State varies greatly across the different climatic zones found within the state. The average surface life of pavements west of the Cascades is 16.7 years, compared to 10.9 years for pavements east of the Cascades and as low as 5 years in mountain pass areas. Currently, Washington State Department of Transportation (WSDOT) standards specify only two standard PG binders with the standard one or two grade bump to account for the climate conditions. This study evaluates potential material and construction practices to improve the longevity of pavements in the harsh climates of Eastern Washington and mountain pass areas. Promising strategies for improving pavement performance are determined from a literature review, survey of state agencies, and interviews of industry professionals. Performance history within the Washington State Pavement Management System (WSPMS) is analyzed to determine the causes of pavement failure within these climatic zones and verify the promising methods/technologies from the literature review, survey of state agencies, and interviews of industry professionals to determine if these methods/technologies have been tried in the state. Performance tests are conducted on field cores and extracted binders from some in-service pavements in Washington to quantify the effects of some of the methods/technologies. Recommendations for strategies to improve pavement performance are made for project-specific factors of traffic volume and historical failure modes.