GCL hydration under simulated daily thermal cycles

ABSTRACT: The hydration of three different geosynthetic clay liners (GCLs) subjected to daily thermal cycles was examined for a range of subsoil conditions. It was shown that daily thermal cycles can significantly decrease the equilibrium gravimetric moisture content of the GCL to as low as 15% of that under isothermal conditions in the worst case. For silty sand (SM) foundation soil with an initial gravimetric moisture content of 16%, the type of GCL had a significant effect on the daily variation in moisture content which ranged between 13% for one type of GCL and only 2% for another. The effect of these daily variations in moisture content on susceptibility to shrinkage is discussed. The initial moisture content and associated matric suction of the foundation soil was shown to have the dominant effect on GCL hydration. For GCLs over silty sand with initial moisture contents, wfdn, of 5, 10 and 16% and initial suction levels greater than their air entry value, the daily thermal cycles controlled GCL hyd...