<p><p><figure id='attachment_3455' style='max-width:477px' class='caption aligncenter'><img class="wp-image-3455 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph showing the prime coat application on top of geocomposite membrane." width="477" height="353" /><figcaption class='caption-text'> Prime coat application on top of geocomposite membrane (Elsiefi et al. 2001).</figcaption></figure></p><p><div><h2>Project Summary/Scope:</h2>The Virginia Smart Road, located in Southwest Virginia, is a full-scale research facility for pavement research and evaluation of Intelligent Transportation System (ITS) concepts, technologies, and products. The flexible pavement part of the Virginia Smart Road test facility consisted of 12 heavily instrumented sections. Seven of the 12 sections were located on a fill, and the remaining 5 sections were located in a cut. Pavement section length varied between 76 and 117 meters with an average length of approximately 100 meters. The Virginia Smart Road will be a 9.6-km connector highway between Blacksburg and I-81 in Southwest Virginia after completion.</p><p>Subsurface Conditions: SM-9.5A, SM-9.5A with high laboratory compaction, SM-9.5D, SM-9.5E, SM-12.5D, SMA-12.5, and Open Graded Friction Course (OGFC) were the HMA wearing surfaces used in the construction. The OGFC wearing surface was 19 mm thick and the remaining all were 38 mm thick. A BM-25.0 layer, 225-mm thick, was used as an HMA base layer. Three sections were built without OGDL; seven sections were treated with asphaltic cement and two with Portland cement whose thicknesses were kept 75 mm throughout the project. A 21-B aggregate layer, 150‑mm thick, was placed over the subgrade with and without a geosynthetic as a subbase layer.</p><p>The geocomposite membrane was installed underneath an asphalt treated drainage layer to test its effectiveness as a moisture barrier, in Section J at the Virginia Smart Road. Moisture in the pavement sections were measured by using Time-Domain Reflectometry (TDR) and Ground-Penetrating Radar (GPR).</p><p>The area to be covered with geocomposite membrane was cleaned of any loose aggregate before installation. For Section J, five rolls of 37-meter long and 2-meter wide geosynthetics were installed over the complete width of the road and 2.15 meters into the shoulder. Staggered transverse joints were used with an overlap of 85 mm. The longitudinal joints were connected by welding a 55-mm length at the edge of each roll with the application of hot air, which melted the uncovered PVC end. The welding was then carefully checked. The upper surface of the geocomposite membrane was primed by using PG 64-22 asphalt binder at an application rate of 1.5 kg/m2. An asphalt-treated drainage layer 75 mm thick was then placed on top of the geocomposite membrane.<br><h2>Performance Monitoring:</h2>Temperature and moisture sensors were placed on both sides of the geocomposite membrane to obtain information regarding moisture content in the pavement section.</p><p>The geocomposite membranes were effective in maintaining for long-term constant volumetric moisture content over different precipitation periods and increasing the service life of the pavement whereas moisture content in the section without geocomposite membranes varied with the amount of precipitation and service life of pavement reduced.<br><h2>Project Technical Paper:</h2>Elseifi, M.A., Al-Qadi, I.L., Loulizi, A., and Wilkes, J. (2001). “Performance of geocomposite membrane as pavement moisture barrier.” <em>Transportation Research Record 1772,</em> TRB, 168-173.<br><h2>Date Case History Prepared:</h2><strong> </strong>November 2012</p><p></div></p></p>