Mechanical and Functional Properties of Continuously Paving Functional Asphalt Mixture with Double-Gradation Based on Different Volumetric Ratios

Abstract

This study aims to design a double-gradation functional asphalt mixture considering continuous paving action and to investigate the effect of different gradation volume ratios on the mechanical behavior and functional performance of double-gradation asphalt mixture. The open graded friction course (OGFC) and asphalt concrete (AC) gradations were selected as the upper and lower layers of the double-gradation asphalt mixture. Three double-gradation volume ratios (2∶1, 1∶1, and 1∶2) were considered to compare the high- and low-temperature performance, water stability, permeability, and noise reduction coefficient of asphalt mixture with different gradation combinations. In addition, a discrete element numerical model based on a digital image processing technique was developed to analyze the mesoscale mechanical response and damage behavior of the double-gradation functional asphalt mixture. The research results show that the crack width and initiations of the double-gradation asphalt mixtures reduced significantly with the increasing volume percentage of AC-graded mixtures, while the larger OGFC- graded volume ratios are more conducive to functionality of the double-gradation asphalt mixtures. In addition, the volume ratio of OGFC-AC double-gradation asphalt mixture can be selected in the range between 1∶1 and 1∶2, which can simultaneously satisfy the mechanical properties and functionality of large pore asphalt pavement.