Design and performance of UHPC-based honeycomb protective structures with multi-scale mechanisms
摘要
In response to the increasing demand for reliable traffic accident and explosion impact protection, traditional collision avoidance facilities (e.g., steel guardrails and ordinary concrete piers) face limitations such as brittle failure, low durability, and secondary debris hazards. This study investigates the application of ultra-high performance concrete (UHPC) in impact-resistant structures and proposes a “material-structure-monitoring”trinity design paradigm. At the material level, nano-SiO2 modification combined with steel and PVA fibre reinforcement and 90℃steam curing achieved a compressive strength of 180 MPa and a dynamic strength enhancement factor (DIF) of 1.44 at 103 s−1 strain rate, with strength increasing by 18–22% per strain-rate order of magnitude. Structurally, a biomimetic honeycomb topology integrated with high-strength bolts, mortise-tenon joints, and prestressed self-restoring systems demonstrated an energy absorption efficiency > 80 kJ/m3, a peak acceleration < 15 g, and a residual deformation < 0.2% in full-scale crash tests (MASH TL-4 standard), outperforming traditional reinforced concrete and steel guardrails by over 100% in energy absorption and by 40% in deformation control. Multi-scale experimental validation through SHPB tests, X-CT damage characterization, and LS-DYNA simulations revealed a synergistic mechanism of fibre bridging and stress wave dissipation, with the modified Johnson–Cook model achieving R2 > 0.95 accuracy. Whole life cycle assessment further confirmed that UHPC structures reduce carbon footprint by > 40%, extend service life to > 100 years, and lower total life-cycle cost by approximately 30% compared with conventional materials. These results provide robust theoretical and engineering support for high-end protective applications, such as nuclear power plant explosion-proof walls and seismic bridge piers.