Electrically conductive cementitious composite (ECCC) is a multifunctional material utilized in structural health monitoring (SHM), electromagnetic shielding, and pavement deicing. The addition of nano-graphite (NG) in ECCC can prominently enhance the electrical behavior and improve the mechanical strength due to its filling of molecular pores. Besides, magnetite can replace part of graphite owing to its excellent mechanical performance. To enhance molecular dispersion and bring out the potential of the composite, three various modifying treatments were carried out. This paper explored the modifying effects of alkali excitation, ultrasonic vibration coating, and combined activation on magnetite-nano-graphite incorporated ECCC. In total, 360 ECCC specimens were proposed for electrical resistance, compression strength, and flexural strength. The results indicate that chemical activation facilitated the pozzolanic reactivity of fly ash-cement system. Meanwhile, the ultrasonic vibration prompted the uniform distribution of magnetite-nano-graphite. The combined surface treatment is superior to any single treatment, endowing ECCC balanced in great mechanical properties and electrical conductivity. A 6 wt% ratio of NG, 60 wt% of magnetite with combined activation is illustrated as the optimum design with 6.92 MPa of flexural strength, 46.75 MPa of compressive strength, and 3430 Ω cm of resistance. Finally, a microstructure analysis of ECCC was performed by SEM to investigate the conductive mechanism and a schematic diagram was proposed.

导电水泥复合材料(ECCC) 是一种多功能材料，用于结构健康监测 (SHM)、电磁屏蔽和路面除冰。在 ECCC 中添加纳米石墨 (NG) 可以显着增强电性能并提高机械强度，因为它填充了分子孔。此外，磁铁矿由于其优异的机械性能，可以替代部分石墨。为了增强分子分散性并发挥复合材料的潜力，进行了三种不同的改性处理。本文探讨了碱激发、超声振动涂层和联合活化对掺入磁铁矿-纳米-石墨的ECCC的改性效果。总共提出了 360 个 ECCC 试样的电阻、抗压强度和抗弯强度。结果表明，化学活化促进了粉煤灰-水泥体系的火山灰反应。同时，超声振动促使磁铁矿-纳米-石墨均匀分布。组合表面处理优于任何单一处理，赋予ECCC良好的机械性能和导电性。6 wt% 的 NG，60 wt% 的磁铁矿与联合活化被说明为具有 6.92 MPa 的抗弯强度、46.75 MPa 的抗压强度和 3430 Ω cm 的电阻的最佳设计。最后，通过SEM对ECCC的微观结构进行分析，以研究导电机制，并提出了示意图。