In the construction industry, waste cement or shelf-life-expired (SLE) cement shows potential sustainability challenges. In geotechnical applications, grout materials are crucial for filling voids, improving load-bearing capacity, and minimising the differential settlement of the ground. Within the scope of this work, an investigation is conducted into the potential use of SLE cement as a binder in cementitious grout for geotechnical applications that require moderate intensity. The mechanical properties were confirmed through the ASTM standard for flexural and compressive strength. Simultaneously, the fresh properties were evaluated using fresh density and fluidity tests, as per ASTM and European standards. Whereas M2-type grout achieved 4.43 MPa (max.) flexural and 23.54 MPa (max.) compressive strength, M1 grout indicated better results with 5.68 MPa (max.) and 33.51 MPa (max.) at 28 days. Fluidity remained within a considerable limit for the injectable grout. This grout can be used in geotechnical applications such as void filling, settlement control in compressible soils, permeation grouting (seepage cut-off), stabilising the subgrade of light pavements, shallow slope stabilisation, temporary groundwater sealing, and soft soil improvement, where volume stability or permeability reduction is more critical than strength. Through effective resource construction and valorisation, this study reduces cement waste and the consumption of manufactured raw materials, thereby supporting the SDGs on Sustainable Cities and Communities (SDG 11) and Responsible Consumption and Production (SDG 12).