Light Weight Deflectometer Evaluation of Low-Volume Road Structural Deterioration under Rapidly Increased Traffic Patterns
Margarita Ordaz, Jesse D. Doyle, Isaac L. Howard
Abstract
When evaluating low-volume road (LVR) condition, there is not a tremendous emphasis on structural capacity, since deterioration is typically caused by environmental factors. However, in cases where LVRs experience rapidly increased traffic loading, structural condition becomes important. The research objective was to determine whether the light weight deflectometer (LWD) can be used as a structural evaluation tool for LVRs. This study explored three major factors that affect measurement of flexible pavement structural capacity: load-induced deterioration (e.g., rutting and cracking), soil moisture, and asphalt temperature. Four full-scale flexible pavement test items were constructed with varying base-course materials and layer thickness typical of LVR. Instrumentation was installed during construction to monitor moisture content, temperature, and ambient weather conditions. Accelerated traffic was applied with a 4-axle military truck. A total of 10,000 cumulative vehicle passes were completed. Falling weight deflectometer (FWD) and LWD testing equipment were utilized to measure pavement structural condition at selected traffic intervals. The LWD was shown applicable for LVRs experiencing accelerated traffic. The LWD is portable and is more efficient for LVRs when high rut depths are permitted. The LWD tracked trends of the FWD; therefore, the LWD, based on these experiments, can be recommended for use in lieu of FWD to assess structural condition in some LVR conditions.