Study on accelerated aging rate of asphalt binder under multi-factors coupling conditions

Abstract

The aging behavior of asphalt binder in service is complex. The accelerated aging methods commonly used in the laboratory are difficult to reproduce the aging behavior of asphalt binder in service. The purpose of this study is to develop a method for predicting the properties of asphalt binder in service. First, a multi-factor accelerating (MFA) aging method was developed to accelerate the aging of asphalt binder. Multi-scale characterization and correlation analysis were conducted on the MFA-aged asphalt binder. Then, the evaluation index of MFA aging was defined, which was used to establish the prediction equation for asphalt binder aging. Finally, the time correlation between field aging, pressure aging vessel (PAV) aging and MFA aging was constructed separately. The results show that accelerated aging of asphalt binder at atmospheric pressure and service temperature can be achieved by the coupled effect of temperature, ultraviolet light and rain. After 5-day MFA aging, the Glover-Rowe (G-R) parameter, an index for evaluating the cracking resistance of asphalt binder, was increased by 308%. The carbonyl index, an index for evaluating the content of chemical functional groups of asphalt binder, was increased by 67%. The correlation between the G-R parameter and the carbonyl index was linear, and the goodness-of-fit was greater than 0.9. The carbonyl index as a key chemical index may reflect the macroscopic properties of asphalt binder. The prediction equation for aging was established based on the carbonyl index of field-aged asphalt binder in Beijing, with reliability greater than 0.98. PAV aging for 20 h was equivalent to 1.35 years of asphalt binder service in Beijing. MFA aging method can better predict the aging time in the field. The prediction accuracy was 97.2%, which was 4.9% higher compared to that of PAV aging. MFA aging for 5 days was equivalent to about 2 years of asphalt binder service in Beijing.