Abstract: The feasibility of utilizing the rock from tunnel excavation materials as the coarse aggregate for high-performance concrete was investigated. The rheological properties of high-performance concrete could meet the specification requirements when the substitution rate of excavated coarse aggregate for fine aggregate was below 40%, while the 7-day and 28-day compressive strengths were decreased by 22.2% and 14.1%, respectively, and the flexural strength didnt change much. Based on the experimental results, the simple-type center of gravity design method was utilized to evaluate the mechanical and rheological properties of high-performance concrete. The stacking densities under different coarse aggregate yields were also calculated in combination with the close packing theoretical model. It is found that the needle-like grain size of the excavated coarse aggregate changes the stacking state of the material and reduces the stacking densities of the high-performance concrete, thus reducing the compressive strength of the high-performance concrete. Finally, scanning electron microscope technique was used to analyze the microstructure of excavated coarse aggregate and natural coarse aggregate high-performance concrete to verify the reason for the decrease in strength of excavated coarse aggregate high-performance concrete.

Key words: materials engineering; excavating coarse aggregate; high performance concrete (HPC); close packing theory; packing density; interfacial transition zone

摘要： 探讨了利用隧道开挖料中的岩石作为高性能混凝土粗骨料的可行性。当粗骨料对细骨料的替代率在40%以下时，高性能混凝土的流变学性能可达到规范要求，但7、 28 d的抗压强度分别下降了22.2%、14.1%，抗折强度变化不大；基于试验结果，利用单纯型重心设计法对高性能混凝土力学性能及流变性能进行了评价；根据紧密堆积理论模型计算了不同粗骨料产量下的堆积密实度，发现开挖粗骨料的针片状粒型改变了材料堆积状态，降低了高性能混凝土的堆积密实度，从而降低了高性能混凝土的抗压强度；采用扫描电镜技术，分析了开挖粗骨料和天然粗骨料高性能混凝土的微观结构，验证了开挖粗骨料高性能混凝土强度下降的原因。

关键词: 材料工程；开挖粗骨料；高性能混凝土；紧密堆积理论；堆积密实度；界面过渡区