将结构型钢纤维(SF)、碳纤维(CF)及纳米炭黑(NCB)作为多相导电材料加入混凝土中，研究了多相导电材料对混凝土开裂后的力学性能、导电性能及裂缝扩展自监测性
能的影响． 建立了混凝土梁的受拉区表面电阻变化率(FCＲ)与裂缝张开位移(COD)之间的关系． 结果表明:导电相材料的加入能够显著提高抗弯强度与弯曲韧性;多相导电材料对弯曲性能及裂缝扩展的自监测性能具有正混杂效应;电阻变化率与裂缝张开位移呈线性关系．

By adding the macro steel fiber (SF),the carbon fiber (CF) and the nano-carbon black (NCB) into the concrete as the multiphase conductive materials,the influences of the SF,the CF and the NCB on the mechani- cal properties and conductivity of the cracked concrete as well as on the self-monitoring performance of the crack development are investigated.Then,a relationship between the fractional change of the surface resistance (FCR) and the crack opening displacement (COD) of the conductive concrete beams is established.The results show that (1) the addition of the conductive materials can greatly enhance the flexural strength and toughness of the con- crete; (2) the hybrid use of the NCB,the CF and the SF shows a clear positive hybrid effect on the flexural beha- vior and the self-monitoring performance of the crack development; and (3) there is a linear relationship between the FCRand the COD.