镀铜钢纤维的分散工艺对废弃陶瓷水泥砂浆压敏性能的影响

Effect of dispersion method of copper-plated steel fiber on piezoresistivity of cement mortar with waste ceramic powder

  • 摘要: 废弃陶瓷粉可提升砂浆基体的电学性能,镀铜钢纤维具有良好的力学、电学和耐腐蚀性,将两者引入到水泥砂浆中可有效改善其导电性能,并赋予其压敏性。镀铜钢纤维在水泥砂浆中的分散状态一定程度上决定了复合材料的导电和压敏性能。因此,本研究制备了镀铜钢纤维增强废弃陶瓷水泥砂浆(SFRCM),分析了镀铜钢纤维的分散工艺(直接倒入和均匀筛入)对SFRCM的电阻率和压敏性的影响。研究结果表明:均匀筛入法可以有效降低纤维分散系数(分散系数越低代表越均匀),降低率可达29.47%,有效减少了镀铜钢纤维在水泥基体中的团聚。与直接倒入法相比,均匀筛入法制备的SFRCM具有更低的直流电阻率,均匀筛入较直接倒入的直流电阻率最大降低率可达13.90%。在不同的试验条件下,与直接倒入法相比,均匀筛入法制备的SFRCM都具有更好的压敏性能,均匀筛入较直接倒入的应变灵敏度增长率最高可达1 432.20%。由电学机制分析可知,相比于直接倒入法,均匀筛入法有助于镀铜钢纤维在SFRCM内形成分布均匀的导电网络,从而改善其压敏性能。

     

    Abstract: Waste ceramic powder can enhance the electrical properties of cement mortar, while copper-plated steel fibers possess excellent mechanical, electrical and corrosion-resistant properties. Introducing both materials into cement mortar can effectively improve cement mortar’s electrical conductivity and endow it with piezoresistivity. The dispersion states of copper-plated steel fibers in the cement mortar undoubtedly play a significant role in determining its electrical conductivity and piezoresistivity. Therefore, this study prepared copper-plated steel fiber reinforced cement mortar with waste ceramic powder (SFRCM) and investigated the effect of two dispersion methods of copper-plated steel fibers, namely direct pouring method and uniform sieving method, on the electrical resistivity and piezoresistivity of SFRCM. The results show that the uniform sieving method can effectively reduce the dispersion coefficient (the lower dispersion coefficient, the more uniform), and the reduction rate can be up to 29.47%, which effectively reduces the agglomeration of copper-plated steel fibers in the cement matrix. Compared with the direct pouring method, the uniform sieving method is more conducive to the reduction of DC resistivity of SFRCM, and the maximum reduction of DC resistivity is up to 13.90%. Under different test conditions, the uniform sieving method can endow SFRCM with better piezoresistivity compared with the direct pouring method, and the maximum improvement rate of strain sensitivity is up to 1,432.20%. From the mechanistic analysis, it is clear that with the uniform sieving method, the copper-plated steel fibers are more likely to form a uniformly distributed conductive network to improve the piezoresisitivity.

     

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