EFFECT OF COMPACTION PRESSURE AND WATER CONTENT ON THE THERMAL CONDUCTIVITY OF SOME NATURAL CLAYS

Abstract--This paper presents thermal conductivity data for highly compacted Ca-smectite, Na-smectite, illite, and palygorskite as a function of density (i.e., compaction pressure), water content, and temperature. All the clays behaved similarly: thermal conductivity increased irectly with density and water content. Specifically, the thermal conductivity increased from 0.63 to 1.32 W/m.K as the dry density increased from 1.2 to 1.8 g/cm 3 (for a water content of 17%). An increase of water content from 6 to 17 % resulted in an increase in thermal conductivity from 0.63 to 1.22 W/m. K (for a dry density of 1.6 g/cma). Differences from one clay to the other were less important. The thermal conductivity (in W/m.K) for constant conditions of 12 % of water and a dry density of 1.6 g/em 3were: Ca-smectite 0.80, Na-smectite 0.74, palygorskite 0.71, and illite 0.69. Heating to 188"C produced only a 10 % increase in the thermal con-ductivity. Key Words--Compaction pressure, Illite, Palygorskite, Smectite, Thermal conductivity, Water content. R6sum6--Cet article pr6sente des mesures de conductivit6 hermique effectu6es sur des argiles hautement compact6es--smectite-Ca, smectite-Na, illite, palygorskite--en fonction de la densit6 (c'est ~ dire de la pression de compaction), de la teneur en eau et de la temperature. Toutes les argiles &udi6es ont le m6me comportement: la conductivit6 thermique augmente avec la densit6 et la teneur en eau. La conductivit