Influence of Hydrodynamic Pore Pressure Damage on the Performance of Hot-Mixed Renewable Asphalt Mixture

Abstract

For evaluating the water stability of hot-mixed renewable asphalt mixture (HRM), the traditional methods are all tested under still water conditions. Except for damage in still water conditions, the hydrodynamic pore pressure generated by the tire driving on the surface water has a great impact. Thus, the RAP contents of the HRMs were designed at 0%, 30%, 45% and 60% with AC-25 gradation. Then, the self-designed evaluation methods of water stability and dynamic modulus were studied. Finally, the mechanism of the influence of hydrodynamic pore pressure damage on HRMs was studied. The results show that the water stability of HRM containing 30% RAP is equivalent to that of 45% RAP, and the water stability of HRM containing 60% RAP decreases significantly. The Contabro test after MIST treatment can be used as an evaluation method for hydrodynamic pore pressure damage on HRM. Low-speed, heavy-load traffic and larger RAP content have greater damage to the mixture after hydrodynamic pore pressure damage. The performance differences between the aged bitumen and pure bitumen, as well as the aged minerals and new minerals, are continuing to be enlarged in hydrodynamic pore pressure conditions, finally affecting the water stability and dynamic modulus of the HRMs.