Modification of cementitious composites with graphene oxide and carbon nanotubes

Abstract

Both graphene oxide (GO) and carbon nanotubes (CNTs) are carbon-based nanomaterials. Due to their favorable dispersibility in water and excellent mechanical properties, they are potential additives for use as reinforcements in cementitious composites. In this laboratory study, GO and CNTs were simultaneously used as additives to improve the mechanical properties (e.g., compressive strength) and durability (e.g., frost resistance, water impermeability) of cementitious composites. To maintain and optimize the mortar fluidity, fly ash (20% by the mass of the cementitious materials) was also added into the cementitious composite. Based on the laboratory test results, the compressive strength of the cementitious composite was maximized to 43.50 MPa with an optimal dosage of 0.08% GO, by weight of the total mixture. Addition of 0.04% GO (by total mixture weight) and higher dosages of up to 0.08% exhibited a strengthening effect on the cement composites due to the simultaneous bridging effect of 0.15% CNTs and the nucleation effect of GO. Furthermore, the addition of GO and CNTs contributed to improving the freeze–thawing resistance and impermeability of the cementitious composites. Overall, the study results indicated that the addition of GO and CNTs could potentially improve the mechanical properties and durability of cementitious composites, which could be very beneficial for various industrial applications such as concrete roads or building constructions.