Evaluation of the influence of water and temperature on the rheological behavior and resistance to fatigue of asphalt mixtures

- Complex modulus and fatigue tests with and without immersion in water.
- Degradation of asphalt mixtures during cycles of immersion and drying.
- The effect of water and temperature on the rheological-mechanical performance of asphalt mixtures.
- Introduction of the damage factor (D) into the Huet-Sayegh model.

Damage caused to asphalt layers by the action of traffic load, along with water and temperature, is the main factor responsible for the progressive deterioration of pavement structures. Although many studies have been carried out and the effect of water on asphalt mixtures has been reported, this phenomenon is not yet taken into consideration in models for dimensioning the thickness of asphalt layers. This paper reports the results of a study on the effect of water and temperature on the rheological behavior, complex modulus and fatigue resistance of an asphalt mixture formulated with a conventional asphalt binder with a penetration grade of 30/45. This evaluation was carried out through 2-point bending (2PB) tests, where trapezoidal specimens were submitted to wetting-drying cycles at 60 °C and then tested with immersion in water at different temperatures. On comparing the results with those obtained from specimens tested without conditioning and immersion and employing Huet-Sayegh's rheological model with the introduction of the damage factor (D), it was possible to evaluate the effect of the action of water and temperature on the graphical representation of the complex modulus and on the reduction in the fatigue life of the asphalt mixture. The results obtained highlight the need to take into account the action of water and temperature on the dimensioning of the thickness of the asphalt layers as well as on the prediction of the lifespan of these coatings, mainly in regions with a tropical climate.