Type of Document Dissertation Author Wang, Dong Author's Email Address wangd@vt.edu URN etd-06212011-152105 Title A micro-scale method to associate the fatigue properties of asphalt binder, mastic and mixture Degree PhD Department Civil Engineering Advisory Committee
Advisor Name Title wang, Linbing Committee Chair Batra, Romesh C. Committee Member Dove, Joseph E. Committee Member Sotelino, Elisa D. Committee Member Keywords
- Asphalt mixture
- Fatigue
- X-ray Tomography
- Finite Element Method
Date of Defense 2011-02-25 Availability restricted Abstract The fatigue damage is one of the most common distresses observed on the asphalt concretepavement. The initiation and propagation of the fatigue damage is a complicated phenomenon
and very difficult to detect. In order to thoroughly understand the fatigue of asphalt concrete, the
behaviors of the key components of asphalt concrete under cyclic loading are investigated
respectively. A new experiment method is developed to test the performances of asphalt binder,
mastic and mixture under cyclic loading, which provides a tool to unify the fatigue test method
for both binding medium and asphalt mixture. Using the new fatigue test method, the effects of
loading magnitude, temperature and loading rate to the performance of the asphalt binder under
cyclic loading are estimated. Mastic and mixture specimens are prepared by adding fillers and
controlled-size aggregates into the asphalt binder. The effects of filler content to the performance
of mastic specimen are discussed. The differences between the test results of mastic and mixture
are compared and analyzed. Incorporated with the new fatigue test, x-ray tomography system is
used in this study to: 1. Analyze the structure change of the mastic specimen before and after the
fatigue test. 2. Compare the void content differences between the mastic and mixture specimens.
3. Reconstruct the 3-D internal structures of mastic and mixture specimens to build up the digital
specimens. The digital specimens are used in the fatigue simulation of the asphalt binder, mastic
and mixture specimens based on the finite element method. The asphalt binder, filler and
aggregate are treated as different materials. Damage parameter is introduced to model the
degradation of elastic modulus of the asphalt binder caused by fatigue damage. Direct cyclic
analysis available in ABAQUS is used to obtain the response of the material after large number
of loading cycles. The basalt fibers are dispersed into the asphalt binder and mastic specimens,
the effects of the basalt fiber to the performances of the binder and mastic at low temperature are
analyzed using both experimental and FEM modeling methods.
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