Ground characteristics are of utmost importance to construction in geotechnical engineering and when designated as inappropriate, they need to be reinforced to attain the proper strength. In this research, the effect of consolidated grouting on the mechanical behavior of rock joints was investigated. This study is deemed important as the mechanical properties of joints are of an imperative impact on estimation of the mechanical properties of the rock mass in geotechnical designs. In this regard, the different methods of measuring and calculating the deformability modulus of rock mass were initially investigated to better highlight the significance of joints mechanical characteristics in geotechnical calculations. One of the deficiencies is employing dissimilar natural joints, which was resolved in this research by replicating similar artificial joints from real models (natural joints in the Chamshir dam). In order to devise these joints, dental silicone was utilized to produce molds from the natural rock joints and then dental gypsum was cast in the molds. The mechanical properties of the replicated artificial joints were measured. In order to investigate the effect of grout on the joints mechanical features, grouts with the water-cement ratios of 1:1 and 2:1 were used. Following the grouting process, the samples were exposed to 100% moisture for 7 days and then subject to direct shear tests in concrete molds. After the elapsed time of 28 days and with the grout having acquired its peak strength, the artificial joints aforementioned underwent direct shear tests. The tests performed in this research were in form of direct shear with constant load and shear displacements and forces were measured during the tests. Afterward by means of the information obtained, the curves of shear stress versus shear displacement were drawn and the shear stiffness, peak shear stress, and residual shear stress were then determined. In the next step using these stresses, the curves of shear stress versus normal stress were established to calculate and compare the values of cohesion and friction angle corresponding to each curve. Ultimately, it was concluded that grouting is of a positive effect on the shear strength of the rock joints; however, the amount of increase in shear strength is highly dependent upon the grout characteristics and the observations show that with the ratio of water to cement decreasing, the compressive strength of the grout increases but higher increase in rock shear strength will not be necessarily associated.