Characterization of interlayer mechanical performance of double-layer porous asphalt compacted by three methods: Simulations and observations

Abstract

The compaction method directly governs the interlayer patterns, which significantly influence the performance of asphalt pavement. The objective of this research aimed to investigate the interlayer mechanical performance of double-layer porous asphalt (DLPA) samples compacted by three methods: hot-on-cold (HoC), hot-on-warm (HoW), and hot-on-hot (HoH). The interlayer patterns at the upper-lower layer interface of DLPA samples were measured by the thin aluminum sheet and oil-saturated paper and characterized by the modified Weierstrass-Mandelbrot (W-M) function with two fractal parameters. The virtual direct shear test and pull-off test were conducted on the simulated DLPA samples incorporating interlayer patterns. The interlayer mechanical strengths from simulation were verified by laboratory experiments. The results showed that the fractal dimension and scale parameter in the modified W-M function characterized the interlayer patterns. The DLPA samples using HoH compaction exhibited the highest shear and tensile strengths that were inversely proportional to the fractal dimension, owing to the interlocking interlayer pattern generated. The HoH method was recommended to compact the DLPA pavement if the double-layer asphalt paver was available. The findings are useful to improve construction quality of the DLPA pavement.