The qualifications of bentonite as a soil sealant

Abstract

Wyoming bentonites have been used as liners to impound solid and liquid waste for several decades. The information in the scientific and engineering literature dealing exclusively with bentonites has been rather scant to this date. There is no shortage of information on clays in general. The bentonite producers are probably the ones which have the most data and experience with bentonite liners, but many keep their data confidential. The purpose of this paper is to assist the engineer who designs liners in his approach, and to avail some of the data on bentonite—waste interaction which the author has collected over a period of 10 years. Bentonites are applicable in many stressed situations, if the engineer and the contractor know how to deal with it and understand the limitations of the material. A bentonite can degrade in its swelling ability due to organic and inorganic contaminants, but it can also be rejuvenated by addition of sodium carbonate in clean water, although its swell will not be as high as initially. This paper presents an overview of the data collected during the author's activity in the bentonite business, and of published data and descriptions of bentonite liner practices in the United States.