Principal Investigator(s):
Jialiang Le, Professor, Civil, Environmental and Geo-Engineering
Project summary:
It is widely acknowledged that early detection of material damage and timely rehabilitation can lead to a significant reduction in the lifecycle cost of asphalt pavements. This project investigated the capabilities of damage detection and healing of graphite nanoplatelet (GNP)-taconite-modified asphalt materials. The first part of the research was concerned with the application of GNP-taconite-modified asphalt materials for damage detection using electrical conductivity. It was shown that, as compared to conventional asphalt materials, the GNP-taconite-modified asphalt materials exhibited 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 was 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 project investigated 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 was verified by a set of semi-circular beam tests. Finally, microwave heating technology was 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.