Predicting the strain-hardening behaviour of polyethylene fibre reinforced engineered cementitious composites accounting for fibre-matrix interaction

Mechanical properties of engineered cementitious composites (ECC) are highly dependent on the pore structural characteristics and fibre-matrix interaction. The relationship between them has not been extensively explored. This paper proposes a practical micromechanical analytical model accounting for pore structure characteristics and crack-bridging properties to predict the strain-hardening and multiple microcracking behaviour of ECC. Using polyethylene fibre reinforced ECC (PE-ECC) as an example, Monte Carlo simulations were undertaken to investigate the tensile behaviour in terms of crack strength, fibre bridging strength and uniaxial tensile properties against heterogeneity of material property, which were validated with experimental data. A parametric study was then conducted to estimate the effects of fibre-matrix bond and fibre properties on stress-strain relationship and microcracking features of PE-ECC. Results indicate that the tensile properties of PE-ECC can be reasonably predicted. Under constant fibre dosages, the tensile ductility of PE-ECC is dominated by interfacial bond , followed by fibre location, orientation and diameter. Such insights are helpful to the design of ECC composites for practical applications.