This study aims to improve the flexural strengths of Portland composite cement (PCC)-based mortar with the addition of turbulence-assisted shear exfoliation (TASE) graphene and turbulence-assisted shear exfoliation—high shear exfoliation (TASE-HSE) graphene. The mortars were prepared by mixing fine aggregate, cement, and water, and graphene with variations in composition (0%, 5%, 10%, and 15% wt cement). The flexural strength was tested following ASTM C293/C293M, porosity was determined following ASTM C624, chemical composition was probed by Raman spectroscopy, and surface morphology was analyzed using scanning electron spectroscopy (SEM). Flexural strength showed that the optimal composition of graphene added was 10% wt cement. With the addition of graphene, reduced the degree of mortar porosity, when graphene TASE + HSE was added, which was about 7.3%, compared to the addition of TASE graphene, which was 6.1%. Raman spectroscopy analysis showed that the addition of graphene increased the hydration process in such a way that there was a structure reduction of alite and belite. The surface morphology of the mortar with graphene additives was composed of a granular structure and was more porous than the morphological structure of PCC-based mortar without graphene.