Instrumentation of Field-Testing Sites for Dynamic Characterization of the Temperature-Dependent Stiffness of Pavements and Their Layers

Falling weight deflectometer (FWD) tests are performed worldwide for assessing the health of pavement structures. Interpretation FWD-measured surface deflections turns out to be challenging because behavior structures is temperature-dependent. In order investigate influence temperature on overall performance and stiffness individual layers, sensors, asphalt strain gauges, accelerometers were installed into one rigid (concrete) two flexible (asphalt) structures, mostly at layer interfaces. Three different methods installation gauges compared. From correspondingly gained experience, it recommended install a steel dummy as place-holder hot immediately after their construction right before compaction, replace with actual sensor next layer. Concerning first data obtained from dynamic testing field-testing sites, FWD temperatures deliver, expected, deflections. As pavement, sledgehammer strokes onto metal plate, transmitted via rubber pad, yield accelerometer readings that allow detection curling (=temperature-gradient-induced partial loss contact concrete slab lower layers). absence curling, here-proposed quantification runtime longitudinal waves through asphalt, cement-stabilized, unbound such can quantified using theory elastic wave propagation isotropic media.