A simplified test and analysis procedure for fatigue characterization of asphalt mixtures

Title: A simplified test and analysis procedure for fatigue characterization of asphalt mixtures
Author(s): J. S. Daniel, Y. R. Kim
Paper category : conference
Book title: Fifth International RILEM Conference on Reflective Cracking in Pavements
Editor(s): C. Petit, I.L. Al-Qadi and A. Millien
Print-ISBN: 2-912143-47-0
e-ISBN: 2912143764
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 131 - 138
Total Pages: 8
Nb references: 12
Language: English

Abstract: Fatigue cracking is one of the major distresses affecting the performance and life of an asphalt concrete pavement. Fatigue cracking can be initiated at the bottom of the asphalt layer due to tensile flexural stresses, or at the surface of the asphalt layer due to tensile stressed developed from the interaction between truck tires and the pavement surface. The tensile stress-strain behavior of asphalt mixtures must be understood to address both bottom-up and top-down fatigue cracking. Due to the viscoelastic nature of asphalt materials, the fatigue performance of a particular mixture will change depending upon the temperature, frequency and magnitude of loading. To test these various conditions in the laboratory would require an extensive amount of time and materials. This paper presents a methodology by which the material response under various uniaxial tensile testing conditions (type of loading and temperature) can be predicted from the material response obtained from a single testing condition. The methodology is developed from a uniaxial constitutive model for asphalt concrete and simplified for more practical applications. The advantage of a simplified model over a simple model is that a simplified model can account for many different conditions due to its theoretical foundation. The constitutive model is based upon Schapery's elastic-viscoelastic correspondence principle and work potential theory, a continuum damage theory based on the thermodynamics of irreversible processes. This theory has been successfully applied to asphalt concrete materials by several researchers. Uniaxial tensile testing of cylindrical specimens is performed under a controlled crosshead mode for both cyclic and constant rate to failure tests. The cylindrical test specimens are fabricated using a Superpave gyratory compactor in the laboratory. Continuous cyclic fatigue testing is performed at various strain amplitudes and frequencies at several test temperatures. Constant rate (monotonic) tests are performed at several rates and temperatures. A single characteristic curve can be found that describes the reduction in material integrity as damage grows in the specimen, regardless of the applied loading conditions (cyclic versus monotonic, amplitude/rate, frequency). The characteristic curve at any temperature where viscoelastic material behavior dominates (i.e., insignificant viscoplastic behavior) can be found by utilizing the time-temperature superposition principle and the concept of reduced time. In this study, eight WesTrack mixtures were tested and the methodology was applied to successfully predict the fatigue damage at different testing conditions from a single condition. The proposed test and analysis procedure for the fatigue characterization of asphalt mixtures based on this methodology can greatly reduce the amount of testing that must be performed and the corresponding time and materials required. The test and analysis procedure can be advantageous for any application in which the fatigue behavior under a variety of testing and environmental conditions needs to be determined. This process may be applied to both practical situations that agencies deal with on a daily basis, and any potential research that requires such information.

Online publication: 2004-04-15
Publication type : full_text
Public price (Euros): 0.00