Effects of Tire Pressures and Test Temperatures on Permanent Deformation of Direct Coal Liquefaction Residue Mixture

Suo Zhi,Ji Jie,Zhang Ran,Wang Zhe,Yao Hui,Jin Dongzhao

doi:10.3389/fmats.2020.00246

Abstract

This main objective of this research is to investigate the permanent deformation of the asphalt mixtures added direct coal liquefaction residue (DCLR) under various tire pressures and temperatures. Three types of asphalt mixtures, including control/DCLR /composite-DCLR modified asphalt mixture, were prepared by the Marshall design procedure. The rutting test was conducted under various tire pressures changing from 0.7 MPa to 1.0 MPa with a 0.1 MPa interval and at temperatures varying from 55oC to 70oC with a 5 oC interval. Moreover, the dynamic stability and rutting depths were obtained to evaluate the resistance of permanent deformation withthree types mixtures. It was found that the rutting resistance of three mixtures declines with the increased tire pressures and temperatures at various rates. The mixture containing DCLR present has a lower rutting depth and higher dynamic stability compared to the control group asphalt mixture under the conditions. Furthermore, the rutting resistance of composite-DCLR added asphalt mixture is better than that of DCLR modified asphalt mixture. It indicates that the DCLR is favorable for the improvement of rutting resistance. Moreover, the ANOVA was applied, in which analysis results showed that the parameter of the temperature is more sensitive than the tire pressure. Based on the least square procedure, the relationship between dynamic stability and rutting depths is obtained, and the accuracy of the prediction is acceptable.

Highlights

Direct coal liquefaction residue (DCLR), the main by-product from the direct liquefaction process of coal, contains 30% by weight raw coal
The results illustrated that the addition of DCLR into virgin asphalt binder could be a powerful approach to enhance the rutting resistance of asphalt mixture
The main purpose of this research is to evaluate the permanent deformation of DCLR and composite-DCLR modified asphalt mixtures under various tire pressures and temperatures

Summary

Introduction

Direct coal liquefaction residue (DCLR), the main by-product from the direct liquefaction process of coal, contains 30% by weight raw coal. Based on its performance characteristics, such as high softening point and asphaltene percentage, DCLR has been utilized to modify virgin asphalt binder to improve its high-temperature performance and has the potential to apply as an asphalt modifier (Shu, 2003; Gu, 2012). Ji et al (2014), Ji J. et al (2015) studied the properties of asphalt binders containing DCLR and found that the DCLR additives improve the high-temperature properties but lower the low-temperature properties of asphalt binders. The performance of DCLR modified asphalt mixture was studied. The results illustrated that the addition of DCLR into virgin asphalt binder could be a powerful approach to enhance the rutting resistance of asphalt mixture. The rutting resistance and moisture susceptibility of DCLR and composite-DCLR modified asphalt mixture are even better than those of asphalt mixture modified by styrene–butadiene–styrene (SBS) (Moghaddam et al, 2011; Zhao and Ji, 2014)

Objectives

Methods

Results