Reproduction of Geogrid In Situ Damage Used in Asphalt Concrete Pavement with Indentation Tests

Geogrids are used for the rehabilitation of cracked pavements. To ensure an efficient reinforcement, it is required to know the residual mechanical properties of the geogrid after its implementation and compaction of the above asphalt concrete layer and the level of damage of the grid. This article presents the results of the national French project SolDuGri dealing with pavement reinforcement by geogrids and more precisely the reproduction in laboratory of the in situ damage. In this project, full-scale tests have been performed to evaluate the in situ damage of four different types of geogrids in asphalt concrete pavements. Then, after construction, the geogrids have been recovered from different locations on the field sections, where they had been subjected to compaction. These grids have been subjected to direct tension tests in the laboratory. Laboratory analyses like scanned asphalt concrete and greogrid surfaces have been performed to evaluate indenter shapes. Different sets of indenters have been made, and a laboratory complete study of greogrid indentation tests has been performed with different sets of temperature, indenter shapes, and indentation forces. The first conclusions are that the indenter geometry and the temperature have the main influence on the strength resistance and elastic modulus of the grid. Results obtained after indentation performed in laboratory can be compared to those measured on in situ recovered grids.