The application of geosynthetics (ie geogrids) for the stabilisation of basecourses prepared with a River Run rounded gravel aggregate was investigated.
Reductions in the rate of rut formation by over 50% were observed when geogrids were included either at the basecourse/sub-base interface or at half-height of the basecourse.
The rate of rut formation was reduced further if a square type geogrid was used in place of a triaxial type geogrid. It was found that the basecourse rutted rapidly if the surface was not confined, due to the lack of particle interlock and surface confining stress.
If the surface was confined with a thin (ie < 40mm) asphalt layer to bind together the particles in the surface, then the aggregate provided significant support and reduced rutting by over 90%, even without the addition of geosynthetic stabilisation.
Additional investigation is needed to determine the stress/strain relationships, lifetimes and loads that may be expected to be obtained and supported with different combinations of surface binding and geogrid basecourse stabilisation.
Errata (7 December 2015)
This report was originally published in September 2015.
The report has been significantly revised by the authors, with changes to the text and graphics to correct inaccuracies in the original report.
This second edition of the report, published in December 2015, supersedes the previous edition.
basecourse, discrete element, finite element (FE), geocell, geogrid, geosynthetic, gravel, pavement, repeated load triaxial (RLT), stabilisation