Adfreezing and freeze-thaw effects on the shear strength of the Güngören clay-concrete interface

Abstract

The interaction between soil and structures is significantly affected by freeze-thaw (F-T) cycles, which alter soil strength and deformation behaviour. This study investigates the effects of F-T cycles on the shear strength, adhesion, and interface friction angle of the G & uuml;ng & ouml;ren clay-concrete interface under varying water content. Samples were prepared at 5 % below and 5 % above the optimum water content and subjected to 0, 3, 7, and 10 F-T cycles between-20 degrees C and +20 degrees C. Direct shear tests were conducted under both freezing and thawing conditions. The results indicate that adfreezing, ice bonding at the interface, significantly enhanced the strength of frozen samples with shear strength increasing by 1.6-2.7 times in frozen wet-side samples and 1.05-1.19 times in dry-side samples. After thawing, dry-side samples exhibited strain-softening and reduction in strength 0.80-0.95 times the initial value, whereas wet-side samples largely preserved their strength. Adhesion increased slightly in dry-side frozen samples, whereas in wet-side samples, it increased nearly threefold after the third cycle and then stabilised. The interface friction angle exhibits differenttrends depending on the moisture content and thermal state. These variations are attributed to the combined effects of ice cementation, unfrozen water, particle interactions, and moisture redistribution at the interface.