Flexible contaminant-resistant grout composition and method

A method of protecting a structure against penetration by contaminated water comprising mixing a slurry comprising:

• about 15% to about 85% water;
• about 7% to about 60% water-swellable sodium bentonite clay;
• about 4% to about 35% solid, essentially non water-swellable particulate filler;
• and
• about 0.001% to about 8% of a water-soluble polymer;
• pumping the composition, while in slurry form, to dispose the composition in contact with the structure so that the composition sets in contact with the structure, while maintaining flexibility of the composition after complete curing of the composition;
• and
• wherein the sodium bentonite is rewetted to a moisture content of about 15% to about 45%, based on the dry weight of the sodium bentonite clay, and impregnated with dissolved polymer, extruded, dried to a moisture content less than about 12% by weight and then ground to a particle size less than about 75 .mu.m.

A method of protecting a structure against penetration by contaminated water comprising mixing a slurry comprising:

• about 15% to about 85% water;
• about 7% to about 60% water-swellable sodium bentonite clay;
• about 4% to about 35% solid, essentially non water-swellable particulate filler;
• and
• about 0.001% to about 8% of a water-soluble polymer;
• pumping the composition, while in slurry form, to dispose the composition in contact with the structure so that the composition sets in contact with the structure, while maintaining flexibility of the composition after complete curing of the composition;
• and
• wherein the sodium bentonite is rewetted to a moisture content of about 15% to about 45%, based on the dry weight of the sodium bentonite clay, and impregnated with dissolved polymer, extruded, dried to a moisture content less than about 12% by weight and then ground to a particle size less than about 300 .mu.m.

In a method of protecting a structure against penetration by contaminated water comprising mixing a thixotropic slurry composition and pumping the composition, while in slurry form, to dispose the composition in contact with the structure so that the composition sets in contact with the structure, while maintaining flexibility of the composition after complete curing of the composition, the improvement comprising:

• homogeneously mixing a composition comprising a water-swellable sodium bentonite clay, dried to moisture content of 12% by weight or less, in an amount of about 25% to about 100% by weight of water-insoluble solids in the composition, together with a water-soluble polymer, in an amount of about 0.01% to about 10% by weight, based on the weight of bentonite clay solids in the composition;
• rewetting the sodium bentonite clay with water to a moisture content of more than about 12% by weight, and impregnating the clay with water-dissolved polymer;
• redrying the clay to a moisture content less than about 12% by weight, based on the dry weight of the clay;
• and
• mixing the redried clay and polymer with water to form said thixotropic slurry composition.