Tensile creep of asphalt concrete in repeated loading tests and its effect on energy dissipation

ABSTRACT

Failure of asphalt concrete in repeated loading tests could be due to fatigue or due to creep of the material. In this study, the effect of creep on the damage of asphalt concrete in these tests was investigated. Stress-controlled repeated loading tests were conducted in uniaxial tension at different frequencies. A different stress amplitude was chosen for each frequency so that the initial average stored energy in a cycle remains constant. Results indicate that the tensile creep of asphalt concrete can have a considerable effect on the damage and failure of specimens. The variations of the apparent dynamic modulus and phase angle, and the total dissipation per cycle with time, when appropriately normalised, were found to be nearly independent of the frequency of the test. In addition, the dissipation of energy in these tests that is related to the damage of the material was further evaluated. Several techniques have been suggested in the literature for the calculation of damage-related dissipation. The suitability of these techniques was analysed using the results of the study. The dissipated creep strain energy (DCSE) was found to provide the most accurate characterisation of damage-related dissipation.

KEYWORDS:

• Fatigue
• viscoelasticity
• viscous dissipation
• fatigue dissipation
• asphalt

Acknowledgments

The authors also acknowledge the technical assistance provided by M/s IPC Controls, Australia, during the study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors thank the Department of Science and Technology (Grant No. DST/TSG/STS/2011/46) for funding this study.