For over 30 years soil-cement has been effectively used to line lakes, reservoirs, ditches, and irrigation ponds. More recently, wastewater treatment lagoons, sludge drying and ash settling ponds, and coal storage areas have been lined with soil-cement. In addition to its low permeability, soil-cement also provides a reliable method of slope protection.
Numerous laboratory permeability tests have been performed on various soil-cement mixtures. One study included the addition of lime and fly ash to the mixture. Research has been also conducted on shrinkage cracking in soil-cement and its effect on total seepage.
A large-scale field test to determine seepage through a stairstep constructed soil-cement facing was conducted by the Bureau of Reclamation at the Lubbock Regulating Reservoir in Texas. The study indicated the soil-cement to be quite impervious and that most of the seepage occurred through either shrinkage cracks or along the horizontal contact planes. It also showed an overall decrease in seepage with time.
The U.S. Environmental Protection Agency (EPA) has reported laboratory test results on the compatability of soil-cement to various hazardous and other industrial wastes. The tests concluded that exposure to acids such as from electroplating sludges and acidic steel-pickling wastes should be avoided; however, for toxic pesticide formations, oil refinery sludge, toxic pharmaceutical wastes, and rubber and plastic wastes, soil-cement should perform satisfactorily. For caustic petroleum sludges, compatability tests should be conducted on the specific combination of soil-cement and waste.
This paper will include basic information on soil-cement as a linear material and describe in detail the research work on permeability and compatability testing, which has been briefly mentioned. The design, construction, and performance of some unique soil-cement-lined projects will be also presented as well as information on a new composite soil-cement/synthetic membrane liner system that meets the latest U.S. EPA requirements for containing hazardous wastes.