An Experimental Study on Silt Desiccation Cracking with Different Basal Constraints and Various Humidity

This paper presents the desiccation failure process of geomaterials under controlled environmental conditions. The experiment material, granite powder silt, was tested in a controlled atmospheric chamber that ensures temperature consistency and provides humidity control. A polytetrafluoroethylene (PTFE) mold was used in the setup stages to make sure the samples have the same dimensions. The shrinkage of the silt slabs was subject to different sets of frictional constraints, including a flat PTFE plate, a plate with a 45-degree constraint, and a plate with a 90-degree constraint, to analyze the influence of boundary conditions on the air-entry desiccation cracks. The humidity was kept constant during each experiment and different humidities were applied in the series of experiments to find the role of the evaporation rates (ER) on desiccation cracking. Data including the cracks onsets, crack morphology, mass changes, and the atmospheric conditions during the drying process were recorded and collected while the patterns of cracks, crack onsets with different bottom boundary conditions, and different evaporation rates were calculated and discussed.