Fracture and mechanical behaviour of a mortar reinforced with graphene oxide nanosheets

Abstract

In the present paper, an experimental campaign is carried out on a cement-based material added with graphene oxide (GO) (mortar is reinforced with 0.03% GO nanosheets obtained by means of the Brodie's method), to investigate both the mechanical properties and fracture behaviour of such a composite material. In particular, the flexural and compressive strengths are determined through flexural and compressive tests, whereas three-point bending tests are carried out on prismatic notched specimens to compute the fracture toughness. Moreover, plain mortar specimens are also tested for reference.The addition of GO to the mortar provides an increase of about 4%, 3% and 26% in terms of flexural strength, compressive strength and fracture toughness, with respect to the corresponding values characterising the plain mortar.Moreover, X-ray diffraction and SEM images are employed to analyse plain and GO-reinforced specimens from a microstructural point of view. Ca-rich silicate crystals characterised by a compact polyhedron-like shape are observed in GO-reinforced mortar, whereas elongated Ca-rich silicate crystals are found in plain mortar. The difference in the shape of such crystals seems to be responsible for the above increase in terms of mechanical properties and particularly fracture toughness when GO is added to the mortar.