<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. Manufacturer should be able to provide evidences regarding quality of the geotextiles. All the seams and overlaps should be approved by the site engineer. The geotextile should be covered with minimum of 300 mm of loose aggregate prior to compaction. The aggregate should be compacted with vibratory equipment to a minimum of 95% standard AASHTO density. Geotextile labeling, shipment, and storage should follow ASTM D 4873. The contractor should submit the seam assembly description including seam type, stitch type, sewing thread, and stitch density. The geotextiles should be measured in square meters excluding seam overlaps. Geotextiles must have sufficient grab tensile strength, tear strength, puncture strength, sewn seam strength, apparent opening size, permittivity, and UV radiation stability. Geocomposite must have sufficient transmissivity or drainage capacity.</p><p>Transmissivity values of prefabricated vertical drains and a geonet were determined and compared using the ASTM constant head transmissivity test apparatus and the National University of Singapore (NSU) test apparatus (Chew et al., 2000). Performance of corrugated polyethylene toe drains with a knitted geotextile sock backfilled with a sand envelope material was justified by conducting pipe box test in the laboratory (Swihart, 2000). Christopher et al. (2006, 2010) and Holtz et al. (2008) have a comprehensive list of laboratory tests that ensure quality control for the subgrade, base course, and geosynthetics used in pavement drainage. AASHTO M288-06 is a material specification for geosynthetics used in road construction.</p><p><strong>Accuracy and Precision</strong></p><p>Material properties of geosynthetics and in-situ soil were verified by conducting laboratory tests standardized by ASTM and/or AASHTO. The geosynthetic properties will take fewer tests to maintain accuracy and precision, while tests on in-situ soil will take more tests to maintain accuracy and precision.</p><p><strong> </strong><strong>Adequacy of Coverage</strong></p><p>High-quality geosynthetic products require few samples and tests to obtain representative material properties. Properties of subgrade are often highly variable and thus require a large number of tests. Most base and drainage materials are provided by quarries or suppliers; therefore, their properties are more consistent and require few tests.</p><p><strong>Implementation Requirements </strong></p><p>Cost, personnel, training, equipment, and time required to perform the tests to verify most of the material properties are not excessive, hence implementation requirements are reasonable. However, some special equipment and personnel may be required to conduct specific tests.</p><p><strong>General Comments</strong></p><p>This QC/QA method is mainly used for quality control and applicable to method specification, but can be used for quality assurance if exhumed samples can be obtained. Most of the tests in this method have AASHTO and/or ASTM standards; therefore, they have high accuracy and precision, adequacy of coverage, and are easy for implementation.</p></p>