<p><p><h2>QC/QA Guidelines</h2>Verification of geosynthetic quality is a critical part of QC/QA process. Test samples of the geosynthetic are taken to conduct laboratory experiments to ensure that they pass the strength requirements of the specification.</p><p>Falling Weight Defelectometer FWD tests are used to determine resilient moduli of the flexible pavement layers. The data is analyzed using a computer program to back-calculate subgrade layer modulus from the test data. The modulus can indicate stiffness of each layer. Design values of the resilient modulus can be compared with data from the back calculation. Static plate load and dynamic cone penetrometer tests are also applied to ensure the stiffness of subgrade after construction as QA methods.</p><p>Various types of strain gages can be selected for measuring the vertical strains throughout the cross section. Design methods have a requirement for the rut depth during construction. Laboratory experiments can be performed in order to develop a correction factor for strain measured in the field. Strain gages need to be carefully installed to protect them from moisture and physical damage. The survivability and performance of the instruments should be considered. Additional instruments, such as temperature/moisture sensors, are used to measure soil moisture and temperature changes. These data are used for the calibration of strain gage measurements.</p></p>