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354471 
Journal Article 
Characteristics of Chat-Asphalt for Road Base Application 
Wasiuddin, NM; Zaman, MM; Boyd, DR; Alexander, A; Nairn, RW; Kolothody, N 
2006 
English 
More than 35 million cubic meters of mine chat, a waste material from abandoned lead and zinc mining operations, are presently stockpiled at the Tar Creek Superfund Site. Currently, the Oklahoma Department of Transportation (ODOT) uses a rather small percentage (about 20%) of washed (not raw) chat in hot mix asphalt (HMA). No systematic bench-scale tests, incorporating different percentages of chat, have been performed previously for characterization of raw chat in HMA in an environmentally responsible manner. In order to maximize the use of raw chat in chat-asphalt, three different base mixes having three different percentages of raw chat were prepared according to the Superpave mix design methodology. It is observed that raw chat is an excellent source of aggregate in HMA for road base. As much as 50% raw chat can be used in an S3-type Superpave base mix. Chat-asphalt mixes also did well in performance tests, namely moisture susceptibility, APA rut, and permeability. A suite of environmental tests was performed to examine the leaching potential of heavy metals (lead, zinc, and cadmium) in chat due to dry and wet rut tests, and simulated milling. Test results indicate that chat-asphalt can be used safely as a roadway base. 
Article Subject Terms: Cadmium; Construction materials; Heavy metals; Highways; Leaching; Lead; Recycling; Solid wastes; Waste management; Zinc; Article Geographic Terms: USA, Oklahoma; P 4000 WASTE MANAGEMENT; EE 60 Waste Management