Characterization of permanent deformation of asphalt pavement with rigid base

To better characterize the permanent deformation (PD)of asphalt pavement with rigid base, visco-elastic-plastic damage constitutive model was derived for asphalt mixtures. Dynamic modulus, multi-level interval loading and constant rate compression tests were carried out on typical asphalt mixture (AC-13) to calibrate the proposed constitutive model. A three-dimensional finite element model of rigid base asphalt pavement was created in ABAQUS and validated with flow number tests. The UMAT subroutine characterized the visco-elastic-plastic properties of the asphalt mixture, and the DLOAD subprogram simulated real traffic loads to assess the permanent deformation (PD) under repetitive loading. Results show that the accumulative deformation of the asphalt layer increases continuously with repeated loads, but the increasing rate gradually slows down. Compared to flexible base pavements, asphalt pavements with rigid bases exhibit significantly less total rutting; however, the PD in the asphalt layer increases by 21 %. This highlights the need for anti-deformation design and rutting maintenance for asphalt layers with rigid bases. The PD of the asphalt layer with rigid base was influenced by the trade-off between the stress level and layer thickness. Overall, it follows a pattern of "firstly decreases and then increases" with the thickness of asphalt layer. The appropriate thickness of asphalt layer with rigid base is recommended to be 10-14 cm. Given the uniqueness of PD for asphalt layer with rigid base, the MEPDG rutting model was modified to more accurately predict the PD of asphalt pavement with rigid base. The findings can provide reference for the performance prediction, structural design and material selection of asphalt pavement with rigid base.