<p><p><strong>References:<br></strong><em>AASHTO M288 (2006)<br>Holtz et al. (2008)</em></p><p><strong>Method Summary</strong></p><p>To maintain the quality in the separation construction, base course and subgrade soil properties shall be verified. Geotextile and its properties shall be confirmed before laying on the prepared subgrade or subbase layer. The Contractor shall provide to the Engineer a record stating the name of the manufacturer, product name, style number, and chemical composition of the fibers. The geotextile labeling, shipment, and storage shall follow ASTM D4873. Engineer may be able to specify class of geotextile based on survivability criteria, aggregate thickness, aggregate size, and construction equipment contact pressure. Geotextile shall be verified using the laboratory tests with the strength requirements such as grab strength, sewn seam strength, puncture strength, apparent opening size etc according to ASSHTO M288 (2006). Permeability and permittivity of geotextile should be greater than those of soil.</p><p><strong>Accuracy and Precision</strong></p><p>Laboratory tests on geosynthetics, subgrade soil, and base coarse material are highly accurate, precise, and are standardized by ASTM and ASSHTO. The geosynthetic properties like most manufactured materials will take fewer tests to maintain accuracy and precision, while tests on subgrade and base course will take more tests to maintain accuracy and precision.</p><p><strong>Adequacy of Coverage</strong></p><p>Since most manufactured geosynthetic materials have small variability in properties, a limited amount of tests are enough to cover the properties of the geosynthetic used. However, for subgrade and base course, their properties are more variable and depend on the frequency of the tests.</p><p><strong>Implementation Requirements </strong></p><p>Implementation of standard ASTM tests is straightforward and easy to incorporate into a QC/QA procedure.</p><p><strong>General Comments</strong></p><p>Laboratory tests are the common and accurate way to maintain quality control and quality assurance of the pavement materials. Verification of material properties is well adapted for the quality control and assurance on geosynthetics used for separation in pavement systems.</p></p>