Engineering tests were performed on 40 different types of shales. Both hard and soft shales, as well as shales having histories of embankment failures and shales having little known involvements, were tested. The suitability of ten different slake-durability test procedures were evaluated as a means of broadly characterizing the engineering performance of Kentucky shales. Two procedures devised during the study appeared to better characterize slake-durability properties than procedures previously proposed. Natural water contents and jar slake tests were performed to determine if such tests might provide a fairly rapid means of identifying troublesome shales. The natural water content of a shale was a strong indicator of the slake-durability properties. Swelling properties of ten shale types were examined. A good correlation was obtained between a newly devised slake-durability index and the water content of a shale after swelling was completed. When exposed to water, most of the shales exhibited high swell pressures.

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