Assessment of the effect of temperature variations in falling weight deflectometer deflections for full-depth asphalt pavements

Pavement surface deflections collected from falling weight deflectometer (FWD) tests are widely used to estimate in-service pavement structural conditions and aid in pavement management systems. However, asphalt pavement deflections are affected by variations in temperature due to the viscoelastic nature of asphalt. This study evaluated the temperature effects on field FWD deflections performed at two different temperatures on the same day on three Indiana full-depth asphalt pavement sections. A parametric study was performed using a finite element (FE) model validated by field FWD data. Three different subgrade conditions and seven temperature gradients were simulated using the FE model. Field- and model-based FWD deflections were used to evaluate the accuracy of the AASTHO 1993 temperature correction method. It was found that the AASHTO 1993 method may be insufficient to fully consider the temperature effects on FWD deflections. In addition to temperature changes, the deflection level was found to be a major parameter in the variation of FWD deflections. Higher deflection levels showed higher deflection variation and lower AASHTO 1993 correction method accuracy. • Higher FWD deflection levels increase deflection variations due to temperature. • Higher FWD deflection levels increase the effective distance influenced by temperature. • The AASHTO 1993 temperature correction method loses accuracy as deflection levels rise. • FWD deflection levels should be considered when applying temperature corrections. • Correcting only D 0 may lead to a misinterpretation of deflection basin parameters.