Enhancing mechanical strength of concrete has been fascinated using carbon-based nanomaterials such as
CNT and graphene. The key to improving strength is a dispersion of nanomaterials. A novel method is required to
investigate the dispersion inner concrete nondestructively. In this study, the optical optical properties such as
refractive index and absorption coefficient are measured in nano-cement mortar specimens containing MWCNT and
GO using THz electro-magnetic waves. From the results, the properties of nano-cement mortar are confirmed to be
1.0% to 2.5% higher in refractive index, and –14% to 28% higher in absorption coefficient than those of cement
mortar at the average values. Using these characteristics, visualizing the dispersion of nano-concrete structures
seems possible in future.