A technique for three-dimensional characterisation of asperity deformation on the surface of sheared rock joints

• A technique for three-dimensional characterisation of joint asperity deformation under CNS shear testing is proposed.
• Asperity damage and gouge accumulation during joint shearing are quantified and their influence on stress–strain behaviour is identified.
• The effect of initial normal stress and joint roughness to the asperity deformation is studied.