<p><p><h2>Commentary</h2>Typical contract pay items and units of measurement used for geosynthetic in pavement drainage include:<br><ul> <li>Underdrain by the linear foot (LF) – inclusive of appropriate geosynthetic, underdrain conduit, labor, and equipment</li> <li>Pre-fabricated composite drain by the square yard (SY)</li></ul>Granular material may or may not be used in conjunction with geosynthetics in pavement drainage; additional payment for granular material when used is typical.

<p><p><figure id='attachment_1468' style='max-width:1014px' class='caption alignnone'><img class="wp-image-1468 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph showing an edge drain being placed along side a highway.

<p><p><strong>References:<br></strong><em>Al-Qadi et al. (2004)<br>Christopher et al. (2010)<br>Elseifi et al. (2001)<br>Maser (1996)</em></p><p><strong>Method Summary</strong></p><p>Ground penetrating radar (GPR) is used to estimate the moisture content of granular base layers in pavement sections, preferably one with and one without an open-graded base drainage layer with geotextile filter or a geocomposite drainage system.

<p><p><strong>References:<br></strong><em>AASHTO M288 (2006)<br>ASTM D6707 (2006)<br>Chew et al. (2000)<br>Christopher et al. (2010)<br>Holtz et al. (2008)<br>Swihart (2000)</em></p><p><strong>Method Summary</strong></p><p>Contractor should provide to the engineer a record stating the name of the manufacturer, product name, style number, chemical composition of the fibers and other important information for geotextiles.

<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