无电极电阻率法研究水泥基复合材料的导电机理

采用无电极电阻率法监测了分别掺入碳纤维、钢纤维和碎石骨料的水泥基复合材料在72 h内的电阻率，并用Hymstruc3D建立了微观结构模型分析导电机理。结果表明:水泥浆体的电阻率受电解质液相饱和度、孔隙率及孔结构曲折度的影响。掺入的导电纤维能明显降低水泥基复合材料的电阻率；而掺入骨料时，其电阻率明显增加。水泥基复合材料的导电现象是由水泥浆体中液相离子导电和导电纤维中的电子导电的共同作用所致。水泥基复合材料的电阻率与其导电相的含量密切相关。无电极电阻率法为估算水泥基复合材料中导电相或非导电相的含量提供了新的思路。

Conduction Mechanism of Cement-Based Composite Materials by Non-Contact Resistivity Method

We tested the electrical resistivities of cement-based composite materials with carbon fiber，steel fiber and gravel aggregate respectively during 72 h by the non-contact resistivity method，and the conductive mechanism was proposed based on the microstructure model from Hymstruc3D. The results show that the resistivity of cement pastes is influenced by the electrolyte liquid saturation，porosity and tortuosity of pore structure. The conductive fiber incorporated into cement pastes can significantly reduce the resistivity of cement-based composite materials，while the resistivity increases obviously when the aggregate is added. The electrical conductivity of cement-based composite materials is caused by the combined effect of liquid solution ion conductor and conductive fiber electron conductor. The resistivity of cement-based composite materials is closely related to the content of the conductive phase. The non-contact resistivity method provides a new idea for estimating the content of the conductive phase or nun-conductive phase inside cement-based composite materials.