Damping properties of rubberized asphalt rubber using ultrasonic pulse velocity test

Authors: Krishna Prapoorna Biligiri, Jorge B. Sousa, George B. Way



The objective of this study was to investigate the acoustical damping properties, namely, impedance and effective flow resistivity of several rubberized asphalt rubber mixes using ultrasonic pulse velocity (UPV) test. The dataset used in the study constituted of two reference mixes: a dense and one SMA with fibers compared to an SMA; GAP Graded, and OPEN Graded and a new THINGAP gradation with reacted and activated rubber; and a GAP and OPEN Graded with asphalt rubber. The mixes have crumb rubber ranging from 0 to 2.5% by weight of the mixes. Recently, a new and unique parameter referred to as damping acoustical measurement parameter (DAMP) was conceptualized and developed to characterize noise-damping properties of the different road materials used across the USA and Europe. In this study, DAMP was established for the different RAR mixes. The analyses constituted relating many viscoelastic properties extracted from mechanical tests such as fatigue tests. Relationships were developed between acoustical damping properties and mixture volumetrics such as air voids (porosity), asphalt binder content, and stiffness. This study is envisioned to advance the knowledge pertinent to the acoustical capacity of RAR mixes, which are believed to be noise damping but at the same time have structurally performed very well in the field.

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