Grout-Treated Soil for Low-Permeability Barriers Around Waste Landfills
M. L. Allan and L. E. Kukacka
Appears on pages(s):
compressive strength; flexural strength; grout; permeability; silica fume; soil cement; superplasticizers; waste treatment; Materials Research
The objective of this work was to produce grout-treated soils with permeability coefficients less than 10 -7 cm/s that would be suitable as containment barriers around hazardous waste landfills. The role of such admixtures as superplasticizers and silica fume in grouts for mixing with soil was investigated. Grouts were designed to be used with soil-mixing or jet-grouting techniques for in situ installation of barriers. Materials with a range of soil-cement ratios were tested for permeability and strength under wet and simulated subsurface curing conditions. Permeability coefficients of the order of 10 -10 cm/s were measured for soil cements with soil-cement ratios by mass up to 5, depending on how the materials were cured. The use of superplasticizers in parent grouts to reduce water-cement ratio decreases permeability up to four orders of magnitude compared to soil cements produced from conventional high-water-cement ratio grouts. The significant improvement in performance results in reduced thickness of barriers for hydraulic and physical isolation of contaminants, and hence greater cost effectiveness.