Dynamic testing methods for the stiffness of compacted pavements

The load supporting capacity of compacted soils during road construction is generally estimated by static plate load tests. Despite the wide diffusion of this method, its precision and accuracy has not been yet determined. In this work we evaluated the stiffness of stabilised soils during the construction of a road in Northern Italy through the application of two non-destructive methodologies based on acoustic wave propagation. First, Spectral Analysis Surface Waves were used in situ, monitoring the surface vibration induced by a load impact on the ground. Secondly, the propagation of shear acoustic waves was analysed in laboratory, using piezoelectric transducers specially arranged on representative cylindrical samples of soil, tested in triaxial cell. Preliminary results show that these procedures can be successfully applied to control the homogeneity and bearing capacity of bases, sub-bases and wearing surfaces of road paving structures, also as concerns their durability over time.