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Geogrid stabilized and reinforced base layers with bound superstructure over soft subsoil with high swelling capacity To quantify the stabilization and reinforcement effect of geogrids over soft, expansive clay subgrade, a full‐scale pavement field trial was established in 2018 in a rural residential area, south of Brisbane, Australia. Sections with variable geogrid arrangements were constructed to allow the quantitative assessment of geogrid benefit; both in terms of their initial contribution to composite in‐situ stiffness parameters and their benefit to the long‐term performance of the pavement. On site testing was completed within all trial sections during the project's construction phase, such that the initial state of performance the subgrade and each pavement layer was adequately characterized. The article describes the soil investigations, the construction of the test sections as well as performance monitoring results, three years after the road was opened to traffic. [ABSTRACT FROM AUTHOR]

Experimental studies on the influence of geogrids in unbound base layers In railroad construction, base layers of unbound coarse‐grained material are usually installed between the existing subsoil and the rail track. Geosynthetics, in particular geogrids, are used to improve the system behaviour. The reduction of the base layer thickness by the geogrid is based on empirical approaches. The influence of the geogrid on the load‐bearing behavior of a base course is to be quantified by experimental investigations. The investigation is performed using a downscaled base course material and geogrid. For this purpose, monotonic and cyclic triaxial tests were performed to demonstrate the failure and the cyclic loading behaviour. In the monotonic triaxial tests the specimens were sheared to failure. The positive influence of the geogrids compared to the unreinforced specimens could be quantified. Since the in‐situ stresses are mainly in the service load range and thus the failure state is not reached, but the stress follows a high number of load cycles, cyclic triaxial tests were performed. The test specimens were loaded cyclically in order to investigate the influence of the geogrid on the deformation accumulation. The cyclically loaded specimens thus show the influence of the geogrid on deformation accumulation. As a result, a reduction in deformation accumulation due to the geogrid could be demonstrated. [ABSTRACT FROM AUTHOR]