Experimental and numerical investigation of uniaxial and triaxial behavior in High Performance Engineered Cementitious Composites (HP-ECC)

Engineered Cementitious Composites (ECC) has demonstrated great potential for structural applications due to its ultra-high ductility and excellent crack control. However, existing studies on ECC under complex stress states remain limited, particularly with respect to the fracture characteristics and damage evolution of HP-ECC under varying confining pressures. This study investigates its uniaxial and triaxial behavior under different confining pressures (0, 3, 6, 9, and 12 MPa). Uniaxial tensile tests using Digital Image Correlation (DIC) show controlled crack widths (20–80 μ m) and typical multiple cracking. Triaxial tests reveal that increasing confinement enhances peak stress and axial strain, while Computed Tomography (CT) scans show reduced crack volume and a shift from tensile to shear failure. Among three evaluated criteria, the William–Warnke model fits the failure behavior best. A Weibull-based damage model accurately captures stress–strain responses under varying pressures. These results highlight the strong potential of high-strength ECC for multi-axial structural applications. • Digital Image Correlation (DIC) is used to monitor the full crack development process and quantify crack widths during tensile loading. • Triaxial tests demonstrate enhanced strength and changing failure modes of HP-ECC under increasing confinement. • X-ray CT scanning reveals the evolution of internal fracture morphology under varying confining pressures. • A statistical damage model based on the Weibull distribution is developed to simulate HP-ECC behavior under multiaxial stress.