Direct Shear Test of Sandstone-Concrete Joints

Understanding the shear behavior of sandstone-concrete joints is important for the design and analysis of concrete structures interacting with sandstone, for example rock socketed piles, rock anchors, and dam foundations. This paper presents the results of a laboratory investigation into the shear behavior of Sydney Hawkesbury sandstone-concrete joints with unbonded interfaces. Joint roughness has been simulated using regular triangular asperities and fractal profiles. The tests were carried out in a large direct shear machine (with sample size up to 600 mm in length) under a range of constant normal stiffness and initial normal stress conditions. The tests showed that significant wear of the sandstone surface occurs during shear displacement, and this wear has a significant affect on the behavior of the joints. The laboratory modeling and test results are briefly described, followed by a discussion of the shear behavior of the joints.