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This study deals with the trends of fatigue life between asphalt binders and mixtures using the rate of dissipated energy change (RDEC) approach. To this end, the time sweep and four-point beam fatigue tests were utilized to assess the fatigue life of bituminous materials under different strain amplitudes. The results indicated that the RDEC approach can be utilized as asphalt mix fatigue estimation in terms of asphalt binder fatigue life. A separate unique relationship exists between the fatigue life of asphalt materials and their plateau value (PV) covering different types of materials and strain levels. Furthermore, a fatigue model was developed based solely on the PV values of asphalt binders and mixtures including all the materials and the strain levels used in this study. Results revealed conformity between time sweep and four-point beam fatigue tests in terms of RDEC methodology, and a strong correlation exists between these two fatigue tests. [ABSTRACT FROM AUTHOR]

This paper aims to develop asphalt binder fatigue models by time sweep tests under constant strain. By investigating the fatigue life in neat and modified asphalts under linear and nonlinear viscoelastic responses, results were analyzed in terms of strain levels, asphalt type, and additive content. The dissipated energy and dissipated energy ratio concepts were utilized to develop the phenomenological models for estimating fatigue lives of asphalt binders. Results showed that the dissipated energy ratio-based equations give relatively identical fatigue models irrespective of the strain level or asphalt binder type. Moreover, statistical analyses were performed to investigate the contribution of each parameter in the fatigue model prediction. A comparison was made between fatigue life predictions by means of traditional and energy-based methods. Results proved that the fatigue life prediction models based on the concept of dissipated energy ratio follow a similar trend. [ABSTRACT FROM AUTHOR]

Asphalt mixtures are time, temperature and stress dependent and categorized as viscoelastic materials. A wide range of models have been proposed to characterize the fatigue behavior of asphalt mixtures. In this study continuum damage theory is used to characterize fatigue properties of asphalt binders and their effects on mixture’s fatigue resistance. Neat, polymer modified and nanoclay modified bitumens were tested using linear amplitude sweep test. Four point bending beam fatigue tests were conducted on mixtures made with these binders at different loading rates namely 400, 600, 800 and 1000 micro-strain. Results showed that a strong correlation exists between the viscoelastic parameter of binder’s integrity and the fatigue resistance of asphalt mixtures. Furthermore, a phenomenological fatigue relationship was introduced which is a function of the strain loading of the mixture as well as the viscoelastic continuum damage properties of the binder phase in the mixture. The proposed model can be used as a surrogate to time consuming beam fatigue tests. [ABSTRACT FROM AUTHOR]

In this paper dissipated energy (DE) versus loading cycles is plotted, at the same time fatigue life of asphalt binders were investigated using of dissipated energy (DE) approach and based on linear and nonlinear strain levels. It was found that based on results obtained of time sweep test; there is a fair correlation between dissipated energy at the 50th loading cycle and fatigue life of asphalt binders in all strain levels. As a result, initial dissipated energy (IDE) is a parameter obtained from time sweep test, so the amount of initial dissipated energy (IDE) at the 50th loading cycle can be predicted the fatigue of asphalt binders without performing millions of loading cycles. [ABSTRACT FROM AUTHOR]