Applicability of determination indexes for fatigue failure of modified asphalt

Document Type

Article

Publication Date

2020

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

The malvern dynamic shear rheometer was used to conduct the time sweep fatigue tests on the 90# original binder, SBS modified asphalt, rock asphalt modified asphalt, crumb rubber modified asphalt, rock asphalt/SBS composite modified asphalt and rock asphalt/crumb rubber composite modified asphalt (RA/CRCMA) under the stress-controlled and strain-controlled modes. The corresponding fatigue life of modified asphalt was determined according to five fatigue failure definitions. The suitability of fatigue failure determination indexes of modified asphalt was evaluated by using the statistical analysis method. The fatigue performances of modified asphalts were compared and analyzed by using the recommended indexes. Research result shows that the index determined based on the normalized dynamic modulus is not affected by the load control mode and asphalt type. The indexes determined based on the phase angle and cumulative dissipative energy ratio are significantly affected by the asphalt type and load-controlled mode, and are not universal. The index determined based on the dissipated energy change rate is only suitable for the fatigue life judgment of stress-controlled mode. The index determined based on the reduced dissipated energy change rate is less affected by the asphalt type. It exhibits a preferable fatigue life evaluation effect on all asphalts in this study. The correlation coefficients of the indexes determined by the normalized dynamic modulus and the reduced dissipated energy change rate under the stress-controlled and strain-controlled modes are up to 0.94, and the mean absolute error is less than 20%, showing a good correlation and equivalent fatigue life ranking results. Due to the simple calculation and distinct definition, they are recommended to be used as the determination standard for testing the asphalt fatigue failure in time sweep fatigue test. According to the sequence of fatigue life of asphalts tested by the recommended indexes in this study, the RA/CRCMA with 18% crumb rubber and 5% rock asphalt shows the optimal fatigue resistance under the stress-controlled and strain-controlled modes.

Publisher's Statement

© 2020, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved. Publisher’s version of record: https://doi.org/10.19818/j.cnki.1671-1637.2020.04.007

Publication Title

Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering

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