Analysis of Dynamic Response for Semi-rigid Base Asphalt Pavement Using Accelerated Pavement Test

A test section of asphalt pavement with typical semi-rigid base was constructed to analyze its dynamic response under accelerated pavement tester. The strain behavior inside asphalt layers was measured by installed pavement sensors. A tension-compression process was observed in vertical strain time history curves over one cycle, while longitudinal time history strain curves exhibited an alternating compression-tension-compression course. The characterization of strain responses under different speeds was studied in this paper and it was found that strain amplitude and the duration of high-strain zone increased at both vertical and longitudinal direction of asphalt layers when loading velocity reduced. Moreover, based on test results, the predicted fatigue life of Sup-25 course suggested that lower loading speed resulted in shorter fatigue life. All in all, the increase of vertical and longitudinal strain in circumstances of low velocity more easily caused pavement distresses, e.g., rutting and fatigue cracking.