Moisture uptake and loss of GCLs subjected to thermal cycles from silty sand subgrade

Abstract

The effect on GCL hydration and dehydration, when subject to thermal cycles, of (1) GCL bentonite granularity (powdered vs. granular), (2) GCL geotextile type (scrim-reinforced nonwoven vs. woven), (3) subgrade macrostructure due to fines aggregation, and (4) subgrade density and fines content is examined. Results of 17 hydration tests were assessed for two virgin and deconstructed GCLs placed on a nominally silty sand subgrade at wfdn = 16% during daily thermal cycles when the airspace was heated to 60°C and cooled to 30°C. It is shown that bentonite granularity and mineralogy, the type of carrier geotextile and the subgrade conditions all significantly impact the GCL on cyclic hydration and that the moisture retention of a GCL is dependent on both the type of GCL and the properties of the underlying subgrade.