Fatigue Resistance Evaluation of Modified Asphalt Using a Multiple Stress Creep and Recovery (MSCR) Test

Weiguang Zhang,Gang Xu,Meng Ling,Xiaoming Huang,Jiayue Xue,Tao Ma,Xiao Chen

doi:10.3390/app8030417

Abstract

Fatigue resistance quantification of modified asphalt is typically time consuming and may not correlate well with mixture fatigue test results. In this paper, the applicability of a multiple stress creep and recovery (MSCR) test on asphalt binder’s fatigue resistance was evaluated. Six binder types with a variety of modifiers and different modifier contents were characterized. The MSCR test was conducted and its sensitivity to binder type and additive content under different aging durations was evaluated. Mixture fatigue tests including a semi-circular bending- Illinois flexibility index test and indirect tensile strength were conducted using control base asphalt and SBS modified asphalt. A ranking between the binder MSCR and mixture fracture test results was conducted to check if the MSCR result was representative of the mixture’s fatigue resistance. Results indicate that the MSCR test at intermediate temperatures (20 °C, 25 °C, and 30 °C) can be performed with good repetitions. It was also found that the MSCR test was sensitive enough to differentiate the fatigue resistance among different binder types and additive contents. The ranking analysis shows that the binder MSCR test at intermediate temperatures showed a similar ranking to the mixture’s fatigue tests, indicating that the binder MSCR test could be potentially utilized to represent a mixture’s fatigue resistance where binder selection is a major concern. It was also found that the SBS modified binder showed the best crack resistance and was less affected by aging.

Highlights

G*sin δ was developed as a fatigue cracking parameter during the Strategic Highway ResearchProgram (SHRP) for asphalt pavement
It was found that the multiple stress creep and recovery (MSCR) test was sensitive enough to differentiate the fatigue resistance among different binder types and additive contents
Complex shear modulus (G*) is defined as the absolute value of peak shear stress divided by the absolute value of peak shear strain, whereas phase angel (δ) is defined as the lag between strain and stress peak values due to the viscoelastic property of asphalt

Summary

Introduction

G*sin δ was developed as a fatigue cracking parameter during the Strategic Highway ResearchProgram (SHRP) for asphalt pavement. G*sin δ was developed as a fatigue cracking parameter during the Strategic Highway Research. Complex shear modulus (G*) is defined as the absolute value of peak shear stress divided by the absolute value of peak shear strain, whereas phase angel (δ) is defined as the lag between strain and stress peak values due to the viscoelastic property of asphalt. The G*sin δ was proposed to limit the magnitude of G* and δ to select relative soft asphalt with a high elasticity, and to improve the fatigue resistance of asphalt binder. Anderson et al [1] found that the G*sin δ was able to differentiate various asphalt types and contents in resisting fatigue damage in a linear viscoelastic range.

Objectives

Methods

Results