# Regulation Mechanisms and Evaluation System for the Damping Performance of Crumb Rubber-Modified Asphalt over the Wide Temperature Range

## TL;DR

This study evaluates how crumb rubber modifies asphalt to improve damping and noise reduction in pavements across different temperatures.

## Contribution

The study introduces new indices for quantifying damping performance and identifies optimal crumb rubber content for different temperature conditions.

## Key findings

- Damping performance is mainly influenced by temperature and crumb rubber content, with particle size having a secondary effect.
- Optimal damping at high temperatures is achieved with 20% crumb rubber content, while 25% is best for low temperatures.
- Microscopic analysis shows crumb rubber increases interfacial friction and energy dissipation, aligning with macroscopic damping behavior.

## Abstract

Utilizing waste tire crumb rubber to modify asphalt enhances the damping and noise reduction performance of pavements. This study systematically evaluated the damping performance of crumb rubber–modified asphalt over a wide temperature range. A high-temperature damping index based on the loss factor and a low-temperature energy dissipation ratio derived from the Burgers model were proposed for quantitative characterization. The results show that damping performance is primarily controlled by temperature and crumb rubber content, while particle size plays a secondary role. Increasing crumb rubber content markedly improves damping performance. When the crumb rubber content exceeds 20%, the damping temperature stability, peak loss factor, and its retention tend to level off, whereas the low-temperature enhancement diminishes when the content exceeds 25%. Accordingly, the robust combinations are 80-mesh (≈180 μm) with 20% content for high-temperature conditions and 80-mesh with 25% content for low-temperature conditions. Multivariate nonlinear regression models achieved high predictive accuracy (R2 = 0.927 and 0.985). Microscopic analyses indicate that crumb rubber increases constrained interfacial phases and system viscosity, and partial particle exposure at 20–25% further enhances interfacial friction and energy dissipation, consistent with the observed macroscopic damping behavior. These findings provide a theoretical basis for robust, noise-reducing pavements.