Permeability and strength characteristics of urethane-grouted sand

Urethane is investigated for use as a chemical grout for the formation of hydraulic barriers. The screening of various mixes based on viscosity yielded nine mixes that have a gelation time of 15 minutes or greater with an initial viscosity varying from 43 cP to 212 cP. Using these mixes as grouts, the hydraulic conductivity of the grouted sand ranged from 1x10(-8) mm/s to 5x10(-8) mm/s. A mix consisting of 50% gel time extender (GTE), 45% water, and 5% gel reinforcer (GR) was chosen for further testing because of its abilily to maintain its integrity when submersed in water and Toxicity Characteristic Leachate Procedure Solutions (TCLP#1 and TCLP#2). A swell test on the grouted sand in conformance with ASTM D 4546-90 indicated a 68% swelling strain after 22 days of immersion with no effect on the k value. The undrained, unconsolidated shear strength parameters of the grouted sand were decreased as the test specimens were fully saturated.