Investigating the creep response of asphalt mixtures under waveform loading

The objective of this study was to examine the effect of waveform loading, truck speed levels and varying load pulse duration on the permanent deformation of asphalt mixture. The effect of vehicle speed and axle configuration was converted to pulse period using the length of total space influence domain divided by speed of the vehicle. Same effect was reproduced in uniaxial repeated load permanent deformation test by computing the pulse width and pulse period to evaluate the response of asphalt mixtures. Test was conducted at a single stress level and two temperature levels. Open-graded and dense-graded asphalt mixtures were prepared using two crushing mechanisms (single-stage and two-stage crushed aggregates). The study revealed that pulse duration and axle type related to any waveform have a significant influence on the permanent deformation of the asphalt mixtures as pulse duration depends on the speed of a vehicle and its axle configuration. The two-stage crushed material performed better in the laboratory as compared to the single-stage crushed material, which is in line with the previous study. Statistical analysis revealed that artificial neural network (ANN) can better predict the permanent deformation in asphalt mixtures than other techniques. However, as the data become more complex, ANN’s ability to predict with more accuracy reduces.