A unit cell based three-phase approach for the mechanical characterization of quasi-brittle cementitious composites

•Successfully developed and implemented the three-phase unit cell approach for the mechanical characterization of cementitious composites.•Captured the non-linear deformation behavior in good correlation with experiments.•Established the effectiveness of the three-phase unit cell approach in capturing the non-linearity of the materials considered without sacrificing the simplicity of the unit cell model.•Different parametric studies were also conducted to identify the influence of certain phase characteristics of the unit cell for the materials considered.

A simple two-dimensional Unit cell (UC) with three different mesoscopic phases may be geometrically modeled as a combination of two concentric circles or squares embedded in a square. In this paper, a two-dimensional three-phase UC with a similar design is developed and utilized for modeling the full deformation and failure response of cement based quasi-brittle cementitious composites under compression. It was identified from the numerical investigation that the three-phase design greatly improved the prediction capability of the UC in suitably capturing the material nonlinearity observed experimentally.