<p><p><strong>References:<br></strong><em>Al-Qadi and Appea (2003)<br>Guram et al. (1994)<br>Loulizi et al. (1999)</em></p><p><strong>Method Summary</strong></p><p>Rutting indicates the deformation and wear of the materials in the pavement. The deformation in the pavement may be due to the reduction of the resilient modulus of the base layer. The reduction of the resilient modulus can be occurred due to the migration of the fines from the subgrade into the base material. Hence, rut measurements can be considered as a QC/QA method for the geotextile separation. The measurement can be taken on the pavement sections using a straight edge. The average rut depth for the measurement locations is calculated. A terminal rut depth is specified and the service life of the pavement sections is computed by developing a linear or nonlinear curve to describe the relationship between the development of rutting and cumulative ESALs over time for the sections.</p><p><strong>Accuracy and Precision</strong></p><p>The rut measurement is taken directly on the field and an average rut depth is calculated. A linear or nonlinear correlation curve is used to describe the relationship between the development of rutting and cumulative ESALS to predict the service life. This method indirectly evaluates the benefit of a geosynthetic separator, especially when a control section is available.</p><p><strong>Adequacy of Coverage</strong></p><p>Rut development on the surface of the pavement can be estimated. Adequacy of coverage depends on the frequency of tests and the consistency of field conditions.</p><p><strong>Implementation Requirements </strong></p><p>Measurement of the rut is a straightforward method and can be implemented easily.</p><p><strong>General Comments</strong></p><p>Rut measurement is an important tool to indirectly check the performance of geosynthetics as a separator in a pavement system. The serviceability ratings are useful to determine the effectiveness, or accuracy of a design.</p></p>