Experimental study of the performance of porous ultra-thin asphalt overlay

Porous ultra-thin asphalt overlay (PUAO) is widely used in maintenance and new road surface layers. Since the paving thickness of PUAO is only about 20 mm, it is necessary to study its own performance and the overall performance of the double-layer material formed by the ultra-thin overlay and the under-layer mixture. PUAO and PUAO/asphalt concrete double-layer specimens with different air voids were prepared and the performance of the specimens were studied. The results showed that as the air voids increased from 15.8% to 24.4%, the PUAO's high-temperature rutting dynamic stability decreased, the tensile strength ratio first decreased and then increased and the acoustic absorption coefficient peak value increased gradually, but the peak value of frequency moved from 400 Hz to 1250 Hz. The dynamic stability and low-temperature bending strength of the PUAO/AC-13 double-layer specimens were higher than those of the PUAO single-layer specimens. However, the double-layer specimen had a smaller permeability coefficient than the single-layer specimen. The International Friction Index showed that after 600,000 abrasion cycles, the F60 values of the five PUAOs were higher than those of the DUAO, indicating that the PUAO material had excellent skid resistance performance.