Cause analysis on permanent deformation for asphalt pavements using field cores

• Field core samples were used to evaluate the rutting resistance for different asphalt pavement structures.
• The correlation between two types of repeated load permanent deformation tests was proposed.
• Rutting causes and main factors for different pavement sections were respectively investigated.

Mechanical tests for asphalt mixtures generally use laboratory-produced specimens, which cannot truly represent material properties and construction conditions as they exist in the field. Therefore, field core samples have been increasingly selected for pavement performance testing. In this study, the field sampling and performance survey were firstly conducted on a highway with different pavement structures. Then, a three-dimensional finite element method (FEM) simulation was performed to compare the critical pavement responses related to permanent deformation (shear stress and pavement surface deflection) for different pavement structures. The advanced repeated load permanent deformation (ARLPD) and conventional repeated load permanent deformation (RLPD) tests were respectively employed to evaluate the rutting resistance on selected field cores. After mechanical tests, these specimens were further checked by the extraction and sieving tests. It is found from theoretical analysis that the maximum shear stress occurs at different locations (sublayers) for asphalt layers with different thicknesses. Consistent conclusions can be made from the ARLPD and RLPD tests results. Flow number index Fi shows the best ability to identify the field rutting resistance of asphalt pavements. A fair relationship is found between Fi measured from the ARLPD and RLPD tests. Compared with the control section with dense graded mixtures, heavy-duty long lasting pavement, porous permeable asphalt pavement, and asphalt rubber concrete pavement show superior rutting resistance while thin layer asphalt concrete pavement shows very poor anti-rutting performance at high temperatures. Finally, rutting causes and main factors for different pavement sections were respectively investigated. All these findings in this study are beneficial to accordingly improve the anti-rutting design for various pavement structures in future. The optimized pavement materials, structures, and techniques also have promising applicability prospects.