Experimental investigation on the damage behavior of high-performance engineered cementitious composites subjected to triaxial monotonic and cyclic compression

This research systematically investigates the compression responses and damage evolution of high-performance engineered cementitious composites (HP-ECC) under triaxial monotonic and cyclic compressive loads. A thorough analysis was conducted on the influence of lateral confining stress, ranging from 1 to 20 MPa, on the mechanical characteristics and performance degeneration of HP-ECC. The findings reveal that the application of lateral confining stress significantly enhances the mechanical properties of HP-ECC, particularly in terms of peak stress and peak strain, while exerting minimal influence on the elastic modulus of the matrix. Moreover, the failure surface of HP-ECC, encompassing the compression and tensile meridians along with the deviatoric plane, was effectively characterized using a five-parameter failure criterion. Under cyclic loading, the accumulation of plastic strain exhibits a linear correlation with the envelope unloading strain, decreasing as lateral confining stress increases. Although significant stiffness degradation occurs with an increasing number of loading cycles, this deterioration is mitigated under higher levels of confining stress. Consequently, a robust exponential function incorporating confining stress and unloading strain parameters was proposed to model the damage evolution of HP-ECC. Additionally, an elastoplastic damage model was introduced to accurately characterize the triaxial monotonic and cyclic stress-strain behavior, demonstrating high precision in predicting experimental results from both this study and the existing literature.