Date of Graduation

5-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Engineering (PhD)

Degree Level

Graduate

Department

Civil Engineering

Advisor

Andrew F. Braham

Committee Member

Kevin D. Hall

Second Committee Member

Zahid Hossain

Third Committee Member

Gary S. Prinz

Fourth Committee Member

Shengfan Zhang

Abstract

The application of fracture energy is widely applied in the evaluation of cracking in the laboratory for asphalt concrete. However, this single number does not provide information on the characterization of the initiation and propagation of cracks. The Resistance Curve method, or R-Curve, is widely applied in characterizing various materials including, but not limited to, metal, polymer, rock, and composite. This research R-Curve method introduces asphalt concrete through a stepwise approach. First, in chapter one, there is a literature review of the history of fracture mechanics, fracture research in asphalt concrete, and an examination of the role of R-Curve application in various materials. Second, the current widely applied fracture energy analysis techniques are studied comprehensively for three types of asphalt concrete, three levels of aging, and two levels of moisture condition. The main limitation of fracture energy found in this chapter is that fracture energy alone is not always able to differentiate the fracture resistance of the three different materials examined. Third, the R-Curve method is applied to analyze and evaluate the same materials examined in chapter two. It is found that R-Curve can characterize and quantify the crack initiation and propagation, and the effects of aging and moisture damage on crack propagation are captured. Finally, a further investigation of R-Curve is performed to establish the envelope R-Curve considering the internal factors of aggregate size and binder grade, and the external factors of testing temperature and loading rate. The effects of aggregate size, binder grade, temperature, and loading rate on crack initiation and propagation are found by the parameters of cohesive energy and energy rate that are extracted from R-Curve. In conclusion, it is found that the R-Curve method can characterize and quantify the crack initiation and propagation for asphalt concrete.

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