高性能混凝土在桥梁工程中的创新应用

Innovative Applications of High-performance Concrete in Bridge Engineering

摘要:

系统探讨高性能混凝土（high performance concrete，HPC）及超高性能混凝土（ultra-high performance concrete，UHPC）在桥梁工程中的创新应用与研究进展，分析其技术优势、工程实践及未来发展方向。通过对比普通混凝土（NC）与HPC、UHPC的力学性能、耐久性及施工特性，结合国内外规范标准差异和典型工程案例（英德北江四桥的无横隔板预制拼装技术和全体外预应力体系设计），系统评估了UHPC在桥梁结构中的实际应用效果。研究创新点包括：提出基于纤维长径比参数的UHPC承载能力设计方法，突破欧美纤维取向系数K的技术路径局限；建立“横向分片+纵向分段”预制拼装工艺，实现102 m跨径UHPC箱梁的工业化建造；通过生命周期评价（LCA）量化UHPC桥梁全周期碳减排效益，较钢结构降低了60%。研究结果表明，UHPC凭借其超高强度、优异耐久性及轻量化特性，可显著降低结构自重和碳排放，并延长使用寿命至200 年。然而，UHPC的高成本、复杂施工工艺及长期性能验证仍需进一步研究。可为UHPC桥梁设计规范本土化编制及“双碳”目标下绿色桥梁技术发展提供了理论与工程实践支撑。

Abstract:

The innovative applications and research progress of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC) in bridge engineering is systematically discussed, and the technical advantages, engineering practices and future development directions of these concretes are analyzed. By comparing the mechanical properties, durability and construction characteristics of normal concrete (NC), HPC and UHPC, combined with the differentiation of domestic and international specification standards and the typical engineering cases (such as the diaphragm-free prefabricated assembly technology and fully external prestressing system design of the Yingde Beijiang Fourth Bridge), the practical application effects of UHPC in bridge structures are systematically evaluated. The research innovations include proposing a UHPC bearing capacity design method based on fiber aspect ratio parameters, which breaks through the technical pathway limitations of the European and American fiber orientation coefficient K, to establish a “transverse slicing + longitudinal segmenting” prefabricated assembly process, which achieves the industrialized construction of UHPC box girders with a 102 m span, and to quantify the full-life-cycle carbon emission reduction benefits of UHPC bridges through the life cycle assessment (LCA), which is 60% lower than that of steel structure. The research results indicate that UHPC can significantly reduce the structural self-weight and carbon emissions by virtue of its ultra-high strength, excellent durability and lightweight characteristics, and its service life is extended to 200 years. However, the high cost, complex construction technology and long-term performance verification of UHPC still require further research, which can provide the theoretical and engineering practical support for the localization of UHPC bridge design codes and the development of green bridge technologies under the “dual carbon” goals.