# Study on the Low-Temperature Performance Evaluation Indicators of Asphalt Binder Based on the Poker Chip Test

## TL;DR

This study evaluates how well tensile strength and strain from the poker chip test predict low-temperature cracking in asphalt binders compared to traditional methods.

## Contribution

The study introduces tensile strength and ultimate tensile strain as effective and reliable indicators for low-temperature performance of asphalt binders.

## Key findings

- Tensile strength and ultimate tensile strain of SBS-modified asphalt are higher than 70# base asphalt at the same aging level.
- Both indicators show strong linear correlations with stiffness modulus and creep rate, with coefficients over 0.9.
- Tensile strength increases with aging, while ultimate tensile strain decreases for both asphalt types.

## Abstract

Low-temperature cracking is a primary failure mode of asphalt pavement. The poker chip test provides a straightforward and efficient approach to simulating the film state of asphalt binders in asphalt structures. By measuring the tensile strength and ultimate tensile strain of the binder film, this test can effectively evaluate the cracking resistance and ductility of asphalt binders. Accordingly, this study employed the poker chip test to analyze the evolutions of low-temperature cracking resistance under various aging levels. To ensure the reliability of tensile strength and ultimate tensile strain, a Pearson correlation analysis was conducted between the two indicators and the traditional low-temperature performance evaluation indicators: stiffness modulus, creep rate, and the Glover-Rowe (G-R) parameter. The results indicate that the tensile strength and ultimate tensile strain of styrene–butadiene–styrene (SBS)-modified asphalt are higher than those of 70# base asphalt at the same aging level. With increasing aging time, the tensile strength of both SBS-modified asphalt and 70# base asphalt increases, while the ultimate tensile strain decreases. Additionally, the tensile strength and ultimate tensile strain are sensitive to changes in asphalt binder types and aging levels. They have a good linear correlation with stiffness modulus and creep rate, with correlation coefficients exceeding 0.9. Due to the distinct characteristics represented, the correlation between the two indicators and the G-R parameter is relatively weaker, with correlation coefficients exceeding 0.7. The findings of this study demonstrate that tensile strength and ultimate tensile strain are effective indicators for assessing the low-temperature performance of asphalt binders. They can serve as substitute indicators of stiffness modulus and creep rate, respectively.