Rutting and strain characteristics of rubberized asphalt pavement based on accelerated pavement tester

Abstract

This study aimed to investigate the rutting and strain characteristics of rubberized asphalt rejuvenated reclaimed asphalt pavement (RARR). Accelerated pavement tester (APT) was employed to apply wheel load and tire pressure on the instrumented test field. Seven embedded fiber grating sensors were placed at the bottom of the RARR surface layer to collect strain data. In total, 700,000 wheel passes were applied on RARR pavement in 25 loading cycles. Data on rutting deformation was collected after each loading cycle while strain data was collected throughout the test. Results revealed that RARR pavement presented rapid rutting depth and rutting area increase in the first 100,000 wheel passes. After 450,000 wheel passes, the rut area directly contacted with the wheel load presented an almost constant increasing rate with additional wheel passes, while the influence rut area remained unchanged. As regard to strain at the bottom of the RARR surface layer, it was found that the maximum strain after 100,000 wheel passes reached more than 70% of the maximum strain occurred during the final loading cycle. Large strain differences were found after 300,000 wheel passes and the worst case scenario occurred after 700,000 wheel passes. For strain right under the wheel tracks, results revealed that horizontal strain recovery ability was better than that of vertical strain. Moreover, it was found that wheel loadings actually enhance the strain recovery ability of RARR pavement. This was believed to be caused by the further densification of RARR while loading, which enhanced the elastic recovery ability of RARR asphalt mixture as a whole.