The use of innovative lightweight unbound granular aggregates for road and airfield constructions involves complex challenges related to their mechanical characterization and expected field performance. To analyze the materials resistance to repeated loads the common practice is to perform tests using a large triaxial testing machines. On the other side, as reported in the standards, the resulting ranking of the materials has to be confirmed by means of systems able to provide parameters closer to their real long-term behavior. On these premises a new procedure has been developed for the evaluation of field performance of an innovative recycled lightweight material, the so-called Glass-foam, used for airport embankment applications. The new approach arises from the specifications reported in UNI EN 13286-7 (Cyclic Load Triaxial Test for Unbound Mixtures) and involves the use of Fast Falling Weight Deflectometer (FFWD). This new device has been specifically designed to speed up the testing process (in comparison with the traditional Falling Weight Deflectometer-FWD) allowing the application of a great number of load drops over the same location in a reduced period of time and consequently it could be a feasible device for Accelerated Pavement Testing (APT). The procedure includes the dynamic application at different load levels to measure both the stiffness stress dependency and the relationship between the maximum stress condition and the development of permanent deformations in the material. In this paper are presented the APT field tests which have been performed at Fiumicino Airport (Italy) to validate glass-foam aggregates performance. The new approach has allowed to develop a specific performance criterion based on the accumulation of permanent deformations in the glass-foam layer.

Accelerated Pavement Testing, Light Weight Aggregates, Glass foam, unbound materials, Fast Falling Weight Deflectometer.