Mechanical Behavior and Transport Properties of Cementitious Composites Reinforced with Carbon Nanotubes

The mechanical behavior and transport properties of cement pastes reinforced with various types and amounts of pristine and functionalized carbon nanotubes (CNTs) are characterized for different water to cement (w/c) ratios. The flexural strength, compressive strength, and dynamic modulus of elasticity of CNT-reinforced cement pastes were up to 38%, 58%, and 22% higher than those of unreinforced pastes, respectively. CNTs were also effective in decreasing the drying shrinkage of cement pastes to 87% lower than that of reference pastes at early ages. Water absorption by immersion and capillary absorption could be also reduced as much as 16% and 38%, respectively. Microstructure and thermogravimetric analysis evidenced effective dispersion, microcrack bridging, and nucleation effects of CNT-reinforced cement matrices. Results show that depending on the type and dispersion procedure, CNTs effectively contribute for the reinforcement of cementitious materials, regardless of w/c ratio.