Multi-axial creep testing of multi-axial geogrids Available to Purchase

Geogrids have been used in a variety of applications for stabilisation of the unbound aggregate layer and limiting surface deformations. Their radial stiffness at low strain is critically important for effective stabilisation. Traditionally, radial stiffness of geogrids has been determined through in-air uniaxial tensile tests conducted in various in-plane orientations. However, such tests do not adequately represent the stiffness under multi-axial in-plane loading conditions. To address this limitation, a novel multi-axial creep testing device has been developed. This advanced testing apparatus allows for comprehensive in-plane and in-air uniaxial, biaxial, and multi-axial radial creep tests, providing a more accurate characterisation of geogrid response to long-term loading. Experiments conducted with the new system enabled creep strains and comparison of creep rates under various load orientations. Results indicate that multi-directional loading significantly influences creep behaviour, with noticeable variations in creep strain and deformation rates depending on load orientation. This research highlights the importance of employing multi-axial testing to capture time-dependent response of geogrids under multi-axial loading.