STRESS AND STRAIN MEASUREMENTS IN PAVEMENTS 1992 - 1993

The Road, Traffic and Geotechnical Laboratory at the Technical Research Centre of Finland (VTT) has been developing pavement instrumentation and carrying out field measurements at an instrumented pavement section since 1980. VTT has built strain gauges and deflection rods for bituminous layers, devices to measure contact stress between the tyre and the pavement and pressure cells for unbound granular layers. In addition, strain gauges and acceleration sensors have been installed onto truck axles. The results are used for comparison of the effect of different tyre and axle configurations on pavement behavior and for development of pavement design and rehabilitation methods. Objectives of this study were to simulate Spring thaw period and to measure stresses, strains and displacements induced by the moving wheel load during the thawing process at different ground water levels. The effect of ground water table level on response in high temperatures was studied. The effect of pavement edge on strains in the bituminous layer was also investigated.