Portland cement can be mixed with sand to improve its mechanical characteristics. Considering the inherent anisotropy of most sands, it is not clear whether the added cement shall contribute to equal increases of strength and stiffness in vertical and horizontal directions or not. Literature review reveals that all the previous experimental studies on the cement-treated soil topics are limited to conventional triaxial device test results. The effect of cement addition to clean sand in more sophisticated stress-path controlled devices like "Simple Shear Apparatus" (SSA) and "Hollow Cylinder Apparatus" (HCA) simulating more realistic loading conditions, such as earthquake, have not been investigated yet. This paper presents innovative methods for testing artificially cemented sands through making modifications to the loading platens, specimen molds and specimen preparation methods of SSA and HCA. Undrained tests under different monotonic stress paths were carried out on different mixtures of Portland cement with clean sand to investigate the effect of principal stress rotations. The test results revealed that the cement mixture reduces the anisotropy, while it improves the mixture mechanical properties compared to the compacted uncemented sand.