Conventional backfill for utility trenches often comprises of granular crashed rock, which is Type I subbase material as used in road pavement construction. However, the increasing need to preserve resources and to use recovered and recycled materials led to the consideration of using gypsum as a utility trench backfill material. Thus a range of mixtures containing waste gypsum were investigated. During this study it was found that mixes containing waste gypsum, limestone quarry dust and ordinary Portland cement complied with the existing Specifications for trench backfill in terms of unconfined compressive strength as well as durability in respect of loss of strength on soaking and freeze thaw. Leachate tests showed that sulphate levels were also within acceptable limits.
Bibliographical noteThe full text of this item is not available from the repository. Paper presented at GeoCongress 2008, held March 9-12, 2008, New Orleans, Louisiana, United States.
- waste management