Comparison of Traffic Speed Deflectometer and Heavy Weight Deflectometer Data from Airport Runway Pavement

A study has been carried out using traffic speed deflectometer (TSD) on a runway pavement and it was a pioneering test involving TSD and heavy weight deflectometer (HWD) in Australia. The research studied the characteristics of the velocity slopes of the deflected runway pavement generated from the TSD device. The main objective is to examine the deflection trends generated by TSD and heavy weight deflectometer (HWD) and to establish a correlation between the two devices. TSD was carried out with a 10-tonnes axle load and tyre contact pressure of 760 kPa. The HWD was carried out at an impact test load of 150 kN and the deflections were normalized to impact load of 103 kN at contact stress of 1,450 kPa. Consistent trend lines and pattern of variability of the TSD and HWD deflections were observed along the runway. The TSD and HWD clearly identified the peak and low deflection points at the various sections of the runway. However, the TSD deflections are observed to be lower than the HWD deflection. The key finding from the study indicates that the deflection measurements of the TSD would have to be adjusted by factor of about 3.6 for it to be consistent with the HWD deflection.