Relationship between Asphalt Binder Fatigue Properties and Mixture Fatigue Performance

Abstract

Fatigue cracking caused by repeated traffic loading is one of the major distresses in asphalt pavement. To control fatigue cracking, the current Superpave binder specification requires a maximum value of 5,000 kPa for the binder loss modulus (G*×sin(δ)) at the intermediate temperature. However, recent research has shown that this criterion may not be a good indicator of the laboratory and field fatigue cracking performance of asphalt mixtures. Therefore, it is desirable to identify another binder property and/or test method that can better predict the fatigue cracking performance of asphalt mixtures. The objective of this study was to investigate the relationship between asphalt binder properties and mix fatigue performance, and to find another binder property and/or test method for evaluating asphalt binder fatigue property.

A laboratory experiment including sixteen asphalt binders representing a wide range of performance grades used in the United States was first conducted. Several binder tests were conducted on each binder. In addition, these binders were used in a 9.5-mm nominal maximum aggregate size mix design for uniaxial and flexural fatigue tests. The binder fatigue/fracture properties were evaluated through the following index parameters: modified linear amplitude sweep fatigue life, loss modulus, delta Tc, loss tangent, crossover frequency, rheological index, and Glover-Rowe value. The mix fatigue properties were investigated through the traditional phenomenological approach, the dissipated energy approach, and the simplified viscoelastic continuum damage approach. The relationship between binder properties and mix fatigue performance was then evaluated.

Results of this study indicated that the modified linear amplitude sweep test could be a promising test to evaluate the binder fatigue property as the results from this test exhibited better correlations with mix fatigue performance, compared to the other binder properties.