# The Effect of Material Parameters of Rubber Asphalt Mortar on Its Friction Performance Under Negative Temperature

## TL;DR

This study explores how material properties of rubber asphalt mortar affect its friction performance at low temperatures, revealing key factors that influence tire-pavement friction.

## Contribution

The study identifies CRC and F/B as significant predictors of friction properties in rubberized asphalt mortar under negative temperatures.

## Key findings

- Friction properties increase with higher crumb rubber content and filler-to-binder ratio.
- Larger filler particle sizes and aging have no significant effect on friction performance.
- Higher CRC reduces temperature sensitivity of friction performance.

## Abstract

What are the main findings?
Different rubber asphalt mortars present different frictional properties.Friction properties are positively correlated with CRC and F/B.Friction properties are negatively correlated with filler particle sizes and aging conditions.

Different rubber asphalt mortars present different frictional properties.

Friction properties are positively correlated with CRC and F/B.

Friction properties are negatively correlated with filler particle sizes and aging conditions.

What are the implications of the main findings?
Deepen the understanding of the frictional properties of rubberized asphalt mortar.Address the research gap regarding the frictional properties of asphalt mortar.Promote the development of theories and testing methodologies related to tire-pavement friction.

Deepen the understanding of the frictional properties of rubberized asphalt mortar.

Address the research gap regarding the frictional properties of asphalt mortar.

Promote the development of theories and testing methodologies related to tire-pavement friction.

The objective of this study is to investigate the friction performance between tire rubber and rubberized asphalt mortar. The friction force and dynamic friction coefficient (DFC) were selected as the characterization indexes for the friction performance between the tire and the rubberized asphalt mortar, and the tests were carried out using a friction coefficient tester. The variations in material parameters, namely crumb rubber content (CRC), filler-to-binder ratio (F/B), filler particle sizes and aging conditions of rubberized asphalt mortar on friction properties were analyzed, for which significance analysis was carried out. Results show that rubberized asphalt mortar composed of different material parameters exhibit different friction properties. Filler-to-binder ratio and crumb rubber content were identified as significant predictors of the friction properties in rubberized asphalt mortar, and as these factors increase, the friction coefficient between rubber asphalt mortar and tire rubber is increased. Higher crumb rubber content (30%) reduces the temperature sensitivity of friction. In contrast, an increase in F/B exacerbates the temperature-induced variation in DFC, with F/B = 1.2 showing 2.1% DFC increase from −20 °C to −10 °C versus 0.6% for F/B = 0.6. Filler particle sizes, aging degree, and temperature showed no statistically significant effects on DFC (p > 0.1).