Cyclic plate testing of geosynthetic-reinforced airfield pavements

Numerous cyclic plate load tests have been performed over the past several years to investigate the potential performance benefits of including geosynthetics in paved and unpaved applications. A majority of these studies have focused on relatively thin pavement structures subjected to highway loads. Airfield pavements can be substantially thicker and include multiple aggregate layers, and data are needed to quantify geosynthetic contributions under high contact pressures (CPs). Eleven representative airfield pavement structures (four unreinforced sections, four containing geosynthetics at the subbase−subgrade interface and three containing geosynthetics at the base−subbase interface) were constructed in a laboratory containment facility and subjected to cyclic loading under 1750 kPa simulated aircraft CP. Permanent surface deformation and vertical pressure response data were collected to determine relative improvement when compared with an unreinforced pavement structure and to evaluate the influence of geosynthetics. Some geosynthetics increased the number of cycles to failure, and it was found that some level of permanent deformation (e.g. 25 mm) may be required to engage reinforcing benefits when placement occurs at the subgrade−subbase interface. Changing subbase material from a California bearing ratio of 15–18 to 55 resulted in 1·5 orders of magnitude more cycles to 25 mm of permanent deformation than any of the geosynthetic-reinforced sections evaluated.