A laboratory-scale pavement testing facility with a moving vehicle load can be used to simulate reliably the stresses caused by traffic in the road structure and is therefore well suited to the testing of materials and structures. The measuring system developed here can be used to determine reliably both elastic and permanent deformations within the structure, which, in turn, can be used to determine relative strains.

The mechanical properties of the unbound base course and their significance for the performance of the whole road structure depend on the thickness of the bound layer and the quality of the material. When the asphalt concrete (AC) layer is thin, it would be good to have grading with Fuller's "n" value equal to 0.4 or 0.5 in the unbound base course. When the bound layer consists of very soft asphalt, in turn, it would be good to aim at a grading curve with "n" = 0.5. A large maximum grain size in the base course minimizes both permanent and elastic strains.

Compaction of the unbound layers also has a distinct effect on the mechanical properties of the layer. A high degree of compaction minimizes permanent strains. Effective compaction, however, results in grinding of the materials. The compaction of unbound rough materials and their grinding during compaction can be evaluated with the Intensive Compaction Tester gyratory compactor both quickly and inexpensively.