Soils are subjected to complex boundary stresses such as the combination of compression, extension and simple shear etc. in the engineering of geotechnical structures. Recreating these complex stresses in the laboratory is paramount in understanding the material constitutivity. Hollow cylinder torsion (HCT) testing apparatus is one such device which not only controls the magnitude but also the direction of the principal stresses independently thereby simulating the complex stress conditions in the laboratory. Additionally, geomaterials found insitu are rarely composed on a unitary materials such as sands or clays. Sands have small amounts of cohesion between the grains often caused due to argillaceous or silicious cementing agents. In order to study the mechanical behaviour of cohesive-frictional granular materials, i.e. sands with small amount of cohesion (cementation) are reconstituted and studied in the laboratory using HCT. A slew of experiments are performed on loose cemented sands (4% cement) consolidated isotropically and sheared under different intermediate principal stress ratio. These experiments are analysed in a framework of plasticity theory, and a "failure surface" in stress space is drawn from this data. A compilation of the effects of this small amount of cohesion on the sand matrix is brought forth by understanding the stressstrain response, volume change and friction angle. © The authors and ICE Publishing: All rights reserved, 2015.