<p><p><h2>Project Summary/Scope:</h2>One section at the Virginia Smart Road was instrumented and constructed to quantify its effectiveness as a moisture barrier. In Section J, a geocomposite membrane was installed underneath an asphalt-treated drainage layer to test the membrane’s effectiveness as a moisture barrier.</p><p>Prior to the installation of the geocomposite membrane, a 75-mm 21-B granular subbase was installed in Section J. This is a common environment for the placement of a moisture barrier. At this location, the interlayer should protect the granular layers (subbase and subgrade) from the intrusion of rainwater coming from the top layers. Sandbags held the geocomposite membrane in place and the sand was used later to prevent the membrane from being picked up by truck tires during paving. The upper surface of the geocomposite membrane was primed using PG 64-22 asphalt binder at an application rate of 1.5 kg/m² after one week. Seventy-five millimeters of asphalt-treated drainage layer were then placed on top of the geocomposite membrane. Sand was placed over the geocomposite membrane along the truck wheel paths. After the placement of the asphalt-treated drainage layer, three lifts of 75 mm of BM-25.0 were installed, followed by a 38-mm surface mix (SM-9.5D).<br><h2>Performance Monitoring:</h2>In general, the installation of the instruments was very successful with a total loss of less than 5% of the instruments during construction and less than 14% after one year of service. All layers were instrumented for stress and strain measurements as well as for environmental effects (temperature, frost, and moisture). The moisture variation in the subbase aggregate layer during different precipitation events was continuously monitored using Time-Domain Reflectometry (TDR). The effectiveness of the geocomposite membrane as a moisture barrier is evaluated by two methods: Ground Penetrating Radar (GPR) and TDR.</p><p>The long-term effectiveness of the geocomposite membrane as a moisture barrier was investigated and monitored from January 2000 to August 2001. Over the entire 20-month monitoring period, the measured volumetric moisture content was relatively constant (from 8 to 10%) when the geocomposite membrane was used. This confirms the long-term effectiveness of the geocomposite membrane to act as a moisture barrier.<br><h2>Date Case History Prepared:</h2>November 2012</p></p>