铁道建筑

含粗骨料超高性能混凝土（Coarse Aggregate-Ultra High Performance Concrete，CA-UHPC）在体积稳定性、制备成本等方面具备显著优势。为提出CA-UHPC的关键制备工艺建议，本文通过试验研究了搅拌制度、搅拌设备、成型温度对CA-UHPC的流动性能及力学性能、纤维分布均匀性、微观结构的影响规律。研究表明与浆体阶段加入CA相比，干拌阶段加入CA的UHPC的扩展度及强度降低3%～5%、纤维分布均匀性降低约15%；与搅拌8 min相比，搅拌时间延长一倍的CA-UHPC的相应指标约降低3%～10%、20%。采用圆盘立式强制搅拌机、15～25 ℃的成型温度制备的CA-UHPC具备更高的强度，分析其原因为材料具备更优化的孔径特征和更密实的微观结构。

UHPC with coarse aggregates (CA-UHPC) has significant advantages in terms of volume stability and production cost. To propose key techniques for preparing CA-UHPC， this paper conducted experimental studies to investigate the influence of the mixing regime， mixing equipment， and shaping temperature on the flow properties， mechanical properties， fiber distribution uniformity， and microstructure of CA-UHPC. The results show that compared with adding CA during the paste stage， adding CA during the dry mixing stage reduces the slump and strength of UHPC by 3% to 5%， and the uniformity of fiber distribution by approximately 15%; Compared with stirring for 8 minutes， doubling the stirring time for CA-UHPC reduces the corresponding indicators by approximately 3% to 10% and 20%， respectively. CA-UHPC prepared by the disc vertical forced mixer within the shaping temperature range of 15°C to 25°C has higher strength， mainly because that the prepared CA-UHPC has more optimized pore size characteristics and a more compact microstructure.