A Comprehensive Study of Crack Growth in Asphalt Concrete Using Fracture Mechanics
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Date
2003-10-29
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Abstract
This research presents findings from a comprehensive experimental/analytical study of crack growth in asphalt concrete using the theory of fracture mechanics. The primary objective of this study is to provide critical information that is complementary to the use of viscoelastoplastic continuum damage model (Chehab et al., 2002) in simulating crack growth by means of finite element analysis.
To simulate opening mode fracture, uniaxial-monotonic and cyclic-tension tests were conducted on prismatic specimens with symmetric double notches. The full post-peak behavior with strain localization is well described by softening function and fracture energy using the cohesive crack model. Digital image correlation method (DIC), a non-contact, full-field, surface displacement/strain measurement technique, was utilized to investigate the characteristics of the fracture process zone (FPZ), a localized damage zone. Irrespective of the notch size and testing conditions, the FPZ was observed to be similar in size and shape for the mixture. In addition, it was found that the strain at the crack tip immediately before crack initiation is a decreasing function of strain rate.
It is shown that crack growth rate in asphalt concrete can satisfactorily be predicted using a quasi-elastic approach, based on the linear elastic stress intensity factor criterion. Using a temperature-reduced crack speed concept, the crack growth rate of asphalt concrete was shown to be proportional to temperature.
Finally, the time-temperature superposition principle was successfully applied to these crack growth rate laws to develop a single relationship (i.e., a crack growth rate master curve). This analysis was further implemented to investigate the specimen size effect in the crack growth rate prediction model.
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Keywords
DIC, Fracture Energy, Paris law, FPZ, Softening Curve
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Degree
PhD
Discipline
Civil Engineering
