Moisture and aging damage evaluation of asphalt mixtures using the repeated direct tensional test method

Abstract

This paper addresses three key objectives: the first objective is to develop a repeated direct tensional method using the dynamic mechanical analyser to evaluate the fatigue crack growth of fine asphalt mixtures affected by water vapour diffusion and aging; the second objective is to formulate a fatigue analysis of the data obtained from this test using a modified Paris' law; the third objective is to demonstrate that this method is comparable with recognised full mixtures test method by conducting two independent sets of tests and comparing the results. Both hot mix and warm mix asphalt mixtures were used in the fine aggregate and full aggregate gradation mixtures. To fulfil these three objectives, a detailed testing development and set-up is discussed. Second, a crack growth evaluation using a modified Paris law was formulated. Moreover, the moisture-conditioned and aged specimens were tested using this newly developed repeated direct tension test method and analysed. Finally, two independent sets of tests were conducted on the mixture with the full aggregate gradation and the results were compared to demonstrate the comparability of the new method. It was found that the newly developed repeated direct tensional test greatly reduced the stress state complexity within the specimens by evenly distributing stress over the cross-sectional area of the cylindrical specimen. Compared to the torsional testing method, the newly proposed test protocol is more efficient in characterising the moisture susceptibility and aging of the asphalt mixtures.

Keywords::

• moisture damage
• water vapour diffusion
• Paris' law
• pseudo-strain
• fatigue

Notes

^1. Email: [email protected]

^2. Email: [email protected]