Date of Award

2016

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering (PhD)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Qingli Dai

Committee Member 1

Zhanping You

Committee Member 2

Jacob Hiller

Committee Member 3

Patricia A. Heiden

Abstract

The objective of this doctoral research is to investigate the electromagnetic energy induced self-healing effect of modified asphalt mixture material by developing computational and experimental characterization tools. More than 90% of the pavements in United States are constructed by asphalt mixture. The durability of pavement decreased by distresses has significant impact on maintenance costs. The asphalt mixture has self-healing capability because the asphalt could flow and fill the microcracks if enough external energy can be transmitted to the asphalt mixture system. However, the self-healing capability of asphalt is limited based on the climatic condition and traffic volume. Therefore, it is necessary that a new method named electromagnetic-induced healing needs to be used to accelerate the self-healing process of the asphalt mixture. In this research, different materials were added into asphalt to produce the modified asphalt binder samples and modified asphalt mixture samples, including steel wool, carbon fiber, graphite flake and exfoliated graphite nanoplatelets (xGNP). Some relative asphalt binder tests were conducted to evaluate the performance of modified asphalt, including rotational viscosity, light absorbance, aging and thermal conductivity. Some other tests were employed to evaluate the performance of the asphalt mixture, including disk-shaped compact tension test, dynamic modulus test, and rutting test. Three EM-induced healing approaches were utilized to investigate the induction healing effect of the asphalt mixture material, including the longwave radiation, visible/near-infrared light and microwave healing, respectively. In addition, a multi-phase triangle-shaped finite element bilinear cohesive zone model (CZM) was developed to simulate the fracture behavior of the original and strength recovered asphalt mixture samples during the cyclic fracture-induction healing tests. The digital image correlation (DIC) method was used to analyze the crack displacement variation of the fracture samples. The relative strain ratio was incorporated to determine the recovered fracture energy for the simulation model. The experimental results indicated that three added materials all could increase the healing effect of the asphalt mixture samples. The favorable numerical results compared with the experimental results indicated that the finite element bilinear CZM with defined crack path can be used to predict the recovered fracture strength after fracture-induction healing cycles.

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