Triaxial compressive behavior of UHPCC and applications in the projectile impact analyses

• Optimal UHPCC for protective structures against projectile penetration was prepared.
• Triaxial compressive behavior of UHPCC with confining pressure up to 100 MPa was tested.
• Normalized peak axial strain increases linearly with the rising of confinement ratio.
• UHPCC under triaxial compression obey Willam-Warnke and Power-law failure criteria.
• Strength parameters of HJC constitutive model for HSC were confirmed and validated.

For the constructions of protective structures against potential projectile high-speed impact, the optimal ultra-high performance cement based composite (UHPCC) (straight steel fiber with the volumetric ratio of 2%, high-strength basalt aggregates with the size range of 5-10 mm, the designed uniaxial compressive strength of ∼ 100 MPa) was prepared. By casting two batches of 50 mm × 100 mm cylindrical UHPCC specimens with the uniaxial compressive strengths of 95 MPa and 129 MPa, the triaxial compressive behavior of UHPCC under high confining pressure (up to 100 MPa) was experimentally studied. Based on the deviatoric stress-strain curves under various confining pressure, the failure criteria and toughness of UHPCC under triaxial compression were discussed. At last, the dominant strength parameters of Holmquist-Johnson-Cook constitutive model were confirmed based on the present and existing triaxial compression tests on high-strength concrete. The validity of which was verified based on eleven sets of projectile penetration or perforation tests on concrete-like targets with the uniaxial compressive strength ranged from 60 MPa to 157 MPa.