The temperature effects on hydraulic conductivity of compacted bentonite

The hydraulic conductivities of water saturated Ca-bentonite with dry densities of 1.4, 1.6, and 1.8 Mg/m(3) were measured within the temperature range of 20 to 80 degrees C, The hydraulic conductivities of all the compacted bentonites are lower than 10(-11) m/s, and the relationship between the logarithm of the hydraulic conductivity and the bentonite dry density can be fitted to a straight line. The hydraulic conductivities of bentonites increase with increasing temperature, and the hydraulic conductivities at 80 degrees C increase up to about three times those at 20 degrees C. The measured values are in agreement with those predicted from the hydraulic conductivities at 20 degrees C assuming that only fluid properties are changed with changing temperature. The change in viscosity of water with increasing temperature contributes greatly to the increase of hydraulic conductivity. (C) 1999 Elsevier Science B.V. All rights reserved.