碳纤维粉改性水泥砂浆压阻特性分析

为改善压阻特性，对砂浆掺加CF（Carbon Fiber，碳纤维）粉、硅粉进行改性，开展了试件的压阻测试，并对应变-电阻率曲线进行了分析。结果表明：试件的电阻率随压应变的增加而下降；应力-电阻率曲线可分为接触、承载和破坏阶段；CF掺量为2%时，其灵敏度最高，线性区间最大; CF掺量为2%时，单掺、复掺试件的线性相关系数分别为99.92%和99.45%；CF掺量为4%时，单掺、复掺试件的线性相关系数分别为98.39%和98.33%；CF掺量为6%时，CF粉会出现团聚现象，试件应力-电阻率符合指数关系；在单掺和复掺试件中，4%接近CF粉掺量的逾渗阀值；复掺试件的强度高于单掺试件，Si4/CF4的抗压强度达到52.4 MPa。可见，Si4/CF4试件具有较高的强度、压阻线性度和区间，但其灵敏度、线性区间不及Si2/CF4。

Analysis of Piezoresistance Characteristics of Cement Mortar Mixed with Carbon Fiber Powder

In order to improve the piezoresistance characteristics, the mortar was modified by adding CF powder and silicon powder. The piezoresistance test of specimens was carried out. The strain-resistivity curves were analyzed. The results show that the resistivity of the specimen decreases with the increase of compressive strain. The stress-resistivity curve can be divided into contact, bearing and failure stages. When the CF content is 2%, the sensitivity is the highest and the linear range is the largest. When CF content is 2%, the linear correlation coefficients of single-doped and multiple-doped specimens are 99.92% and 99.45%, respectively. When the CF content is 4%, the linear correlation coefficients of single-doped and multiple-doped specimens are 98.39% and 98.33%, respectively. When the CF content is 6%, the CF powder will agglomerate, and the stress-resistivity of the specimen conforms to an exponential relationship. In the single-dope and multiple-dope specimens, 4% is close to the percolation threshold of the CF powder content. The strength of the multiple-doped specimen is higher than that of the single doped specimen. The compressive strength of Si4/CF4 reaches 52.4 MPa. It is concluded that the Si4/CF4 specimen has higher strength, piezoresistive linearity and interval, but its sensitivity and linear interval are not as good as Si2/CF4.