Evaluation of Susceptibility of Asphalt Binders to Rutting through MSCR Test

Rong Chang,Cong Qi,Songchang Huang,Pinxue Zhao,Aimin Sha,Meng Guo

doi:10.1155/2021/1532994

Abstract

Using modified asphalt binder is one of the most effective methods to solve the rutting problem of asphalt pavement, but the traditional G ∗ / sin δ parameter is not enough to characterize the rutting resistance of modified asphalt in field use. In order to accurately evaluate the high temperature performance of asphalt and establish the relationship between the rutting resistance of binder and mixture, two kinds of matrix asphalt and three kinds of modified asphalt were selected for DSR and MSCR tests. G ∗ / sin δ , nonrecoverable creep compliance Jnr, recovery rate R, and other parameters were used to characterize the permanent deformation resistance of the binder, and the correlation between these parameters and the results of rutting test was analyzed. The results show that Jnr3.2 can accurately characterize the permanent deformation resistance of asphalt, while the stress sensitivity index Jnrdiff is not applicable to all types of modified asphalt. In contrast, Jnrslope can better reflect the stress sensitivity of asphalt, and Jnrslope is significantly correlated with the results of rutting test.

Highlights

Rutting is one of the main forms of pavement damage
Relevant research shows that these indicators have no good correlation with the field performance of asphalt pavement [6]. e asphalt performance grading system of SUPERPAVE measures the rheological properties of asphalt binders at specific temperature and loading frequency through dynamic shear rheometer (DSR) test, and the rutting factor G∗/sin δ derived based on dissipative energy theory is used as the high temperature performance evaluation index for original asphalt and residual asphalt aged by rolling thin film oven (RTFO) test [7]
Temperature Sweep Test. e complex modulus G∗ and phase angle δ were obtained by DSR test, and the rutting factor G∗/sin δ was calculated to evaluate the rutting potential of asphalt. e calculated results are shown in Figure 3. e rutting factor G∗/sin δ decreases with the increase of temperature, indicating that the higher the temperature, the worse the antirutting ability of asphalt

Summary

Introduction

Rutting is one of the main forms of pavement damage. For semirigid base pavement, the cumulative plastic deformation under repeated load is the main reason for rutting of asphalt mixture [1, 2]. e cohesive force of asphalt and the extrusion force between aggregate constitute the rutting resistance of asphalt mixture, of which the contribution of cohesive force of asphalt accounts for about 40% [3,4,5]. The unrecoverable creep compliance obtained by multiple stress creep recovery (MSCR) test is considered to be able to evaluate the rutting resistance potential of asphalt [11,12,13,14]. MSCR test is developed from repeated creep and recovery (RCR) test It evaluates the high temperature rutting resistance of asphalt binder with unrecoverable creep compliance Jnr and recovery rate R and takes Jnrdiff as the stress sensitivity index of asphalt binder. MSCR test leaves a recovery time for the viscoelastic strain generated by the creep part of asphalt after unloading, providing a method to separate the permanent strain from the total strain, which is better correlated with the field rutting [16]. Compared with DSR test, the parameters obtained by MSCR test can better evaluate the rutting resistance of modified asphalt [17, 18]. The asphalt mixture with the same mineral gradation was prepared for rutting test, and the test results of asphalt binder and mixture were compared

Materials and Asphalt Mixture Design

Experimental Program

Results and Discussion

Conclusion