This report documents the performance of highway edge drains in Kentucky. Approximately eighteen high edge drain installations were inspected. The report also documents the laboratory testing, construction, short-term and long-term performance of these systems. Construction inspection and maintenance are addressed.
It is apparent that the panels are distressed more under the old method of installation using excavated trench material and dynamic type compaction. It is apparent that using the sand slurry reduces the chances of installation damage. Proper density needs to be achieved during installation of the sand backfill or damage will occur due to trench settlement. In most cases, increasing the density of the sand increased the performance of the panel drain.
It is apparent through the field analysis that the maintenance and construction of the edge drain systems need to be improved. Field inspections of the headwalls and outlets indicates that approximately 25 percent of the outlets are not properly installed, and that the headwalls are not properly maintained. Inspection data indicate approximately 45 percent of the outlets are partially covered to completely plugged. The center of mass is also located in the rear of the headwall causing the headwall to fill backwards over time.
Soil moisture and thermography data indicate that edge drains help move water laterally across the pavement structure, and that the shoulder acts as a restraining dam for pavements without edge drains.
The gradation analysis performed on the sand backfill from the current edge drain installation specification showed that the sand backfill effectively filters out some of the minus 200 material. Blinding of the sand at this time does not appear to be a problem. Although further testing is needed, preliminary data indicates the sand acts as a filter by not allowing the lines from the broken concrete to flush into the filter fabric immediately after construction.
FWD data indicate that edge drains significantly increase the strength of the subgrade by removing water.
Preliminary analyses of Ride index data indicates that the edge drains may add significant life to the pavement structure. These conclusions are based on data from edge drain systems that are not fully functional.
Digital Object Identifier
Fleckenstein, L. John; Allen, David L.; and Harison, Jack A., "Evaluation of Pavement Edge Drains and the Effect on Pavement Performance" (1994). Kentucky Transportation Center Research Report. 438.