The role of mechanically stabilized base on the performance of top asphalt layer

The paper describes a laboratory study aimed at the influence of a granular layer mechanically stabilized by a multiaxial geogrid as the base on the performance of the top asphalt layer. Full-scale models with standard and composite bases were assembled in the laboratory facility of the Czech Technical University in Prague. Comparative models were dynamically loaded with the same amount of 100,000 loading cycles and equipped with few types of gauges. The settlement of a concrete circular loading plate placed on the top surface of the asphalt layer was a key parameter. Furthermore, observations included a precise deformation of geogrid, deformation of the contact between the asphalt layer and aggregate base, and horizontal pressures on the experimental box side wall as well. Comparison of the performance of the models showed a very positive influence of the mechanically stabilized layer leading even to the possibility of some reduction of asphalt and base thickness. It has economic sense, of course, but it also could solve a lack of proper natural aggregate which is already observed in some regions.