Numerical and theoretical investigation on the constitutive model of graphene-enhanced FRCM composite

One of the limitations of FRCM composite is insufficient impregnation of the cementitious matrix into fibre bundles. Graphene is found to be able to increase the impregnation depth, thereby increasing the proportion of effective fibres in the FRCM composite. As the proportion of effective fibres increases, the level of accuracy of the constitutive model of FRCM composite has more impact on the design of FRCM strengthened reinforced concrete beams. This study aims to understand the tensile behaviour of Graphene-enhanced Fibre Reinforced Cementitious Matrix (GrFRCM) composite and develops an accurate simplified constitutive model for design calculations. Firstly, a numerical model of Gr-FRCM composite plates subjected to uniaxial tension was developed and validated. Afterwards, a parametric study was conducted to investigate the effects of material properties, fibre-matrix interfacial properties and fibre volume ratio on the constitutive model. Both experimental and numerical results were used to assess the accuracy of different existing constitutive models and to identify the key parameters of the constitutive models that require improvement. Proposals to make the aforementioned improvements are suggested. Finally, a work example is presented to demonstrate the varying degrees of accuracy of existing models depending on the penetration depth, and good accuracy of the proposed model.