Laboratory test study on the effect of freeze–thaw cycles on strength and hydraulic conductivity of high water content stabilized dredged sediments

Abstract

Dredged sediments with initial water contents between 200% and 400% were treated with single and composite binders. Samples were subjected to open and semi-closed freeze–thaw (f–t) cycles to investigate the impact of f–t cycling on hydraulic conductivity (HC) and unconfined compressive strength (UCS). A grace period (GP) for thaw consolidation is included to assess healing potential of the affected stabilized mass. Findings of this study show that the impact of f–t cycles depends on initially achieved UCS and HC values prior to the f–t cycling and time of testing after f–t cycles. The HC of specimens with an initial UCS value of 87 kPa increased with number of f–t cycles. The UCS values decreased in the range of 50%–80% when specimens were tested directly after the thaw period and values decreased in the range of 14%–60% when specimens were tested at the end of the GP. The HC of specimens with an initial UCS value of 299 kPa remained almost the same. These samples experienced permanent loss in the UCS values, irrespective of time of testing. Detrimental effects of the freezing action on the UCS were greater under semi-closed than open freezing conditions.