P.I.: Dr. Feng Wang
Institute for Multimodal Transportation
Jackson State University
Pavement warranty is an innovative contracting procedure increasingly adopted by state transportation agencies. Many states view implementing warranties as a way to protect their investment in pavement construction. The major benefit of pavement warranty is enhanced pavement performance. However, establishing warranty criteria and associated distress thresholds to monitor the performance of warranty pavements (maintained projects) is a very important issue that must be carefully studied. Currently MDOT uses converted deduct points to monitor/ evaluate the distresses and the distress thresholds are in the form of deduct points, while many other states use distress indicators and thresholds directly from measurements of pavement distresses or densities of distresses. A recent survey study on pavement warranty programs in the US and Canada revealed that: (1) Although composite indexes are still used for condition evaluation of warranty pavements, the individual distress thresholds are the major criteria used by state DOT’s to manage their warranty projects; and (2) Unlike the practice in Mississippi that uses deduct point based distress thresholds, all the other states that responded with existing warranty programs set their threshold limits based on the maximum allowed quantity of the distress measurement for the distress type.
This research will analytically develop new distress thresholds based on direct measurements of pavement distresses or distress densities for MDOT’s pavement warranty program. Through reviewing the literatures, the state of the practice methodologies of developing pavement distress assessment methods, and pavement performance indicators and associated thresholds are understood. The possibility of including ride quality (roughness) into the current MDOT’s pavement warranty program and issuing an appropriate distress threshold will be investigated. The new performance thresholds will be determined using statistical models and data mining for appropriate ranges of acceptable pavement performance, and with a special consideration for smooth transition from the old deduct point based system to the new system. The development of the new performance thresholds will be conducted by statistically analyzing the pavement data saved in MDOT’s pavement management system (PMS) and especially the distress survey data collected annually for the warranty projects. Analytical capabilities such as statistical distributions and histograms of distress measurements and densities, correlation analyses between distress quantities, distress densities, and deduct points, and regression modeling over the PMS performance and cumulative traffic (time) will be developed for each distress type to establish the new warranty specification on distress thresholds. Case studies will be conducted to check the validity and applicability of the new specification of distress thresholds. In the case studies, the previous cases in which the old thresholds were exceeded will be revisited and rechecked with the newly developed distress thresholds and necessary adjustments are made to have consistency.
The proposed research entails joint efforts that pool expertise from MDOT’s research, maintenance, construction and other related Divisions, and the Institute for Multimodal Transportation (IMTrans), and the Department of Civil and Environmental Engineering at Jackson State University. The successful completion of the proposed study will enhance the MDOT PMS functionalities by providing a more efficient evaluation system for the warranty projects in Mississippi.