Use of accelerated pavement testing to validate Ride Quality Index Data

Abstract

Ride Quality Index (RQI) is the measure used by many state agencies to characterize pavement roughness for construction quality control or in their pavement management systems.The Minnesota Department of Transportation (MnDOT) uses RQI as a basis for determining what the driving public considers acceptable ride quality. To validate this concept, RQI measurements were analyzed for the 22 original asphalt test sections at MnROAD. These pavement test sections were built on the Mainline and Low Volume Road to study their performance under accelerated loading conditions. RQI data was collected twice per year on each section with a Pathways video inspection vehicle, similar to the data collected every year on 12,000 miles of the state highway network in Minnesota. Preventive maintenance treatments were applied at various times to various test sections to repair minor distresses and restore ride quality. This paper discusses the time required for each test section to reach a terminal serviceability level and compares it to the original three, five, or ten-year design life. The paper also considers the ride quality when microsurfacing was applied and the extension in life realized by the maintenance treatment. Finally, the paper examines the distress history within each cell to determine which surface distresses are most responsible for the deterioration in ride quality. The research shows how accelerated pavement testing can be used to validate ride quality concepts used in state pavement management programs. Although no statewide network data is presented in this paper, the MnDOT pavement management program does track the condition of highways over time and is able to quantify the benefits of extended life and reduced costs by applying preventive maintenance treatments.