A non-destructive approach for the predictive master curve of ASPHALT pavements using ultrasonic and deflection methods

The elastic modulus of an asphalt mixture varies with temperature and frequency of load due to its visco-elastic nature, and this behaviour is represented by a master curve constructed by either laboratory tests or predictive models based on known material properties. The predictive approach is based on the material specifications and enables to estimate the modulus over a range of frequency without any laboratory tests. However, this estimated curve should be corrected with respect to a measured reference value, which can be obtained from non-destructive methods. In this study, ultrasonic surface waves (USW) and light weight deflectometer (LWD) tests are conducted on two laboratory slab specimens and an as built pavement, and the experimental results are compared with the predictive master curves. The measured dynamic moduli are found consistently higher than the predictive master curves indicating that the model underestimates the modulus of asphalt mix. Finally, the method is verified by shifting the moduli measured at different frequencies to the 25-Hz-design modulus, of which those obtained by the USW tests from the laboratory and field match very well, whereas those by the USW and the LWD tests from the as built pavement are also found highly consistent with each other.