The introduction of fillers/reinforcement in cement may have both direct and indirect effects. Not only a strong phase can directly contribute to strength and stiffness, but the addition of nano-sized materials can also help to improve electrical conductivity of cement/concrete leading to stronger and more durable products in civil infrastructure and oil&gas applications. Moreover, the high surface area of nanomaterials makes them efficient in controlling the propagation of cracks. However, in the case of carbon-based materials (carbon nanotubes, graphene, carbon fibers), the main issue is related to the poor dispersion and interaction with the matrix. To improve the composite properties, functionalization of the fillers was performed, with the aim to enhance their direct dispersion in water and their interaction with the hydrated cement. The presence of functional hydrophilic groups allows a better dispersion of the reinforcements in water and consequently in the final composite improving also with the chemical structure of the cement, creating secondary bonds between reinforcement and matrix, thus obtaining an evident increase in properties.