基于高性能复配掺合料的大管桩混凝土配合比优化研究

Research on Optimization of Concrete Mix Proportion for Large Pipe Piles Based on High-Performance Compound Admixtures

摘要:

为提升海洋环境下大管桩混凝土的耐久性，保障港口、桥梁等基础设施的安全性与使用寿命，以连云港某港口工程为依托，通过设计5组不同复配掺合料比例（0%、10%、20%、30%、40%）的配合比试验，并结合维勃稠度、抗压强度、电通量及冻融循环测试，系统探究了硅灰、粉煤灰及矿渣粉等高性能掺合料对大管桩混凝土性能的协同优化作用。结果表明，掺入30%高性能掺合料（硅灰：矿渣粉：粉煤灰= 30%：35%：30%）时效果最佳，此时混凝土28 d抗压强度达84.6 MPa，电通量降至453 C，300次冻融循环后质量损失率仅3.9%。研究成果为大管桩混凝土耐久性提升提供了理论与技术支持。

Abstract:

To enhance the durability of large pipe pile concrete in the marine environments, the safety and service life of infrastructure such as ports and bridges should be ensured. Relying on a port project in Lianyungang, by designing five sets of mix ratio tests with different proportions of compound admixtures (0%, 10%, 20%, 30%, 40%), and combined with the Wiber consistency, compressive strength, electrical flux and freeze-thaw cycle tests, the synergistic optimization effect of high-performance admixtures such as silica fume, fly ash and slag powder on the performance of large pipe pile concrete is systematically explored. The results show that when 30% of high-performance admixtures (silica fume: slag powder: fly ash = 30%: 35%: 30%) are added, the effect is the best. At this point, the 28-day compressive strength of the concrete is reached 84.6 MPa, the electrical flux is dropped to 453C and the mass loss rate after 300 freeze-thaw cycles is only 3.9%. The research findings provide a theoretical basis and technical support for improving the durability of large pipe pile concrete.