shear strength behavior of crude oil contaminated sand-concrete interface

a laboratory investigation into crude oil contaminated sand-concrete interface behavior is performed. the interface tests were carried out through a direct shear apparatus. pure sand and sand-bentonite mixture with different crude oil contents and three concrete surfaces of different textures (smooth, semi-rough, and rough) were examined. the experimental results showed that the concrete surface texture is an effective factor in soil-concrete interface shear strength. the interface shear strength of the rough concrete surface was found higher than smooth and semi-rough concrete surfaces. in addition to the texture, the normal stress and the crude oil content also play important roles in interface shear strength. moreover, the friction angle decreases with increasing crude oil content due to increase of oil concentration in soil and it increases with increasing interface roughness.