Weigh-In-Motion/Pavement Instrumentation Along Rt. 15 in Guilford

The Department's Pavement Design methods are based on AASHTO empirical information. Our practice has remained virtually unchanged for many years. The values for hot mix asphalt pavement and base/subbase material (structural layer coefficients) used are based on empirical information from at least 25 years ago. Values for subgrade resilient modulus are based on a best guess. State of the practice pavement designs are including a mechanistic-empirical approach (AASHTO 2002) that takes into consideration the measured material properties and traffic & climate effects. The AASHTO 2002 pavement design guide is based on information gathered from the Strategic Highway Research Program Long Term Pavement Performance program and other national studies. The potential benefits to adopting the 2002 guide include more cost effective designs, ability to more accurately predict pavement performance, and ability to "calibrate" to local conditions. Through a National Science Foundation (NSF) grant and partnership with Worcester Polytechnic Institute and University of Maine, the Department will be constructing a weigh-in-motion pavement instrumentation (WIMPI) site along Rt. 16 in Guilford. The site will allow us to measure the actual distresses in the pavement layers due to traffic loads and climatic changes. This information will be used to modify the current AASHTO design and calibrate the upcoming AASHTO 2002 guide. Phase 1, installation of instruments and short term monitoring, was funded in the FY 04/05 SPR program. Phase 2 will add longer term monitoring of the test site and extensive laboratory and field material testing.