Relationship between the Void and Sound Absorption Characteristics of Epoxy Porous Asphalt Mixture Based on CT

Abstract

This study investigates the relationship between the void characteristics and sound absorption characteristics of an epoxy porous asphalt mixture. The specimens are scanned and reconstructed under different void fractions using X-ray computed tomography (CT) technology and digital image processing, and the sound absorption coefficients at different frequencies are obtained using an acoustic impedance tube. The relationship between void characteristics and sound absorption characteristics is analyzed using gray correlation. The test results exhibited a good correlation between the void characteristics of the epoxy porous asphalt mixture obtained by CT scanning (mesoscale) and the measured values (macroscale). The difference between the void fraction and connected void fraction gradually decreased with an increase in the void fraction. The relationship curve between the sound absorption coefficient and frequency exhibited a bimodal trend, and the peak value of the sound absorption coefficient increased with an increase in the void fraction. The order of the gray correlation degree between the peak and average values of the sound absorption coefficient and the void characteristic parameters is as follows: connected void fraction > void fraction > equivalent diameter of connected void > surface area of connected void > curvature.