Graphene is employed as an additive to enhance the performance of Portland cement composites. The presence of 2-D nano-size graphene improves the nucleation of cement hydrates and the prevention of crack propagation within cement composites. However, the high cost and problems with homogeneous dispersion limit the use of graphene in a cement matrix. To seek low-cost high-performance cement composites, the use of hydrated graphene (HG), a low-cost product with high water dispersibility, was investigated. Cement composites with different HG contents were examined and compared with the corresponding samples with ordinary graphene nanoplates (i.e., dried graphene (DG)) and control sample (without any graphene). The results indicated that HG performed better dispersion and stability than DG. Accordingly, samples using HG gained highest compressive strength and reached a 3-day compressive strength of 61 MPa, which was 42% higher than the control sample (43 MPa).