Evaluate the Impact of Heating and Cooling on the Interface Shear Strength Between Clay and Concrete Surface

This work examined the impact of applying one cycle of heating and cooling on the interface behavior of clay soil to concrete surface as well as the possibility of using heating to enhance the pile’s engineering capacity. To conduct the soil-concrete interface tests, a large-size direct shear test (DST) device with dimensions of 300 mm width by 300 mm length by 200 mm height was modified for this purpose. Low, medium, and high plasticity index (PI) clay soils with PIs of 12, 29, and 60, respectively, were used for the experimental tests. For every normal stress (σn) and clay soil type, two samples were tested at two selected temperatures (~22 ℃, 70 ℃) under various σn values that ranges from 30 kPa to 150 kPa. During the heating process, the temperature of the samples was gradually raised from room temperature to approximately 70 ℃. Then the samples were allowed to return to room temperature. The interface friction angles at peak (δp) and at large-displacement (δLD) for samples exposed to one cycle of heating and cooling experienced substantial increase in magnitude of up to 35%.