<p><p><h2>Project Summary/Scope:</h2>Four full–scale test sections were constructed and loaded with a Heavy Vehicle Simulator (HVS) located at the US Army Corp of Engineers facility in Hanover, NH. The four test sections used three geosynthetics, and a control section. The four test sections (including the control section) were constructed in four quadrants of a 19.82- meter by 6.36-meter by 3.18-meter box. Each quadrant was 9.91 meters by 3.18 meters by 3.66 meters deep.</p><p>Subsurface Conditions: The subsurface consisted of two sections. The first section was an existing subgrade from a previous experiment with 1.35-meter deep AASHTO classification A-2-4 material. The second section of subgrade consisted of 1.37-meter deep AASHTO classification A-7-6 material.</p><p>The second section of subgrade was placed in seven lifts, wetted to the target range and compacted with a 9,000-kg steel wheel roller. The geosynthetic was placed directly on the prepared subgrade. The base coarse aggregate was placed in two lifts of 150 mm and compacted with the steel wheel roller in the static mode. The asphalt layer was placed in two layers for a total asphalt thickness of 75 mm. The testing was performed from October 2000 to July 2001.<br><h2>Performance Monitoring:</h2>Nuclear density, sand cone tests, and oven-dried moisture content readings were taken of the subgrade and base course aggregate. Dynamic cone penetrometer readings were taken of the sub-grade. As-constructed asphalt concrete properties (thickness, density, and air voids) were measured.</p><p>The development of permanent deformation on the pavement surface (rutting) due to permanent vertical strain in the underlying materials (asphalt concrete, base aggregate and subgrade) was the predominant failure mode of the test sections. The sections reinforced with geosynthetic saw an increase to the calculated Time-Domain Reflectometry (TBR).There were some unexpected problems in that the direction of the wheel travel path induced differential pore water pressures across the length of the sections. The latter two sections likely saw a higher pore water pressure that increased rutting.<br><h2>Case History Author/Submitter:</h2>Dr. Steven W. Perkins, Associate Professor<br>Department of Civil Engineering<br>Western Transportation Institute<br>Montana State University - Bozeman<br>Bozeman, MT 59717<br>Stevep@ce.montana.edu<br><h2>Project Technical Paper:</h2>Perkins et al. (2004)<br>Perkins (2002)<br><h2>Date Case History Prepared:</h2>November 2012</p></p>