LONG-TERM PAVEMENT PERFORMANCE SEASONAL MONITORING PROGRAM: INSTRUMENTATION SELECTION AND INSTALLATION

The operational theory of and the installation procedures for the instrumentation selected to monitor changes in internal pavement moisture and thermal regimes and external climate at test sections in the Long-Term Pavement Performance seasonal monitoring study are described. The instrumentation includes time-domain reflectometry probes to measure the moisture contents of unbound materials, thermistor sensors to measure pavement temperature gradients and air temperature, electrical resistivity probes to measure frost locations, a piezometer to measure the depth to the groundwater table, and a tipping bucket rain gauge to measure precipitation. These measurements of the external climate and the resulting changes in the pavement material will be coupled with monthly or more frequent deflection measurements, bimonthly roughness measurements, elevation profiles, and distress surveys to study the causes and effects of seasonal changes in the structural response of pavement. Preliminary results from the instrumentation pilot studies illustrating these types of seasonal effects are presented.