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The 2014 Transportation Asset Management Plan calls for developing a method to annually track, monitor, and identify road segments that have been in poor condition for more than 5 years and consistently consider them when programming. In Minnesota, pavements are considered in poor condition when the ride quality index (RQI) is less than or equal to 2.0. There are still pavement segments that have remained in poor condition for more than 5 years. However, it is not clear if RQI and RSL metrics accurately quantify the "true" condition of the system. In this study, the roadway segments that have maintained a poor ride quality index over time were identified in each district and extensive additional information was obtained from interviews with district engineers and planners. The analysis of the additional information shows that most pavement sections that have remained in poor condition for extended periods are actually not in poor condition. They represent "anomalies" with unique characteristics, and new parameters must be established to quantify the true condition of these sections.

It is widely acknowledged that early detection of material damage and timely rehabilitation can lead to a significant reduction in the life-cycle cost of asphalt pavements. This research investigates the capabilities of damage detection and healing of graphite nanoplatelet (GNP)-taconite modified asphalt materials. The first part of the research is concerned with the application of GNP-taconite modified asphalt materials for damage detection using electrical conductivity. It is shown that, as compared to conventional asphalt materials, the GNP-taconite modified asphalt materials exhibit an improved electrical conductivity due to the electron hopping mechanism. Based on the mathematical analogy between the elastostatic field and the electrostatic field, a theoretical model is derived to relate the change of electrical conductivity to the damage extent of the material. Although, in principle, the material damage can be accessed using the electrical conductivity, the practical application of this method is complicated by the fact that the conductivity is influenced by the moisture content. The second part of the research investigates the damage healing capability of GNP-taconite modified asphalt materials heated by microwave. GNP-taconite modified asphalt materials can effectively absorb the heat generated by the microwave, and the rising temperature can effectively heal the microcracks in the binder. This damage-healing mechanism is verified by a set of semi-circular beam tests. Finally, microwave heating technology is applied to the tack coat system. It is shown that, with microwave heating, the GNP-taconite modified asphalt material can effectively improve the bond strength of the interface of the tack coat system.