Abstract
In this paper, we propose a model of concrete reinforced with graphene and graphene oxide. The thickness of the surface layer of the C–S–H gel is R(I) = 60.3 nm (< 100 nm), i.e. it is a nanostructure according to Gleiter. The equation we obtained shows that the higher the adhesion energy Wa, the more difficult it is to destroy a solid. This means that concrete is easier to destroy by bending than by compression (Waa > Waс). The R(II) layer, which we called the mesolayer, is stronger than the R(I) layer, since γ2 = 3γ1. It differs from the nanolayer and the bulk phase in that the size effects in it occur according to a different type. Here, size effects of the kinetic type are present, associated with temperature, the mean free path of elementary excitations, etc., but they do not exceed 1 micron. At h = R(I), a second-order phase transition (according to Ehrenfest) occurs, the nature of which is described by us using the Landau mean field method. There are no size effects in the bulk phase (larger than 1 micron). It is shown that graphene and graphene oxide are introduced into the interlayer space. Graphene and GO, limited in the interlayer region of the C–S–H gel, demonstrate different morphology. In graphene, carbon atoms, ordered in the xy plane, are distributed far from the C–S–H surface. No expansion along the z-direction is observed. The C–C bonds in GO are stretched in the z-direction, and the graphene sheet is somewhat damaged. Compared to standard concrete, the R(I) and R(II) values decrease by half and the elastic parameters of concrete change. The article shows that the addition of graphene and graphene oxide to cement mortar significantly strengthens (by 4-5 times) standard concrete.