【摘要】 纳米炭黑水泥基复合材料具有导电性和压敏性。试验结果表明,电阻率随炭黑掺量的变化呈现渗滤特征,渗滤区炭黑体积含量为0.6%—1.5%。处于渗滤区和超过渗滤区的纳米炭黑水泥基复合材料的电阻率具有明显的压力依赖性。在受到压应力时,电阻率减小,卸载后电阻回复具有不可逆性。炭黑水泥基复合材料的压敏性与3个因素有关:试件本身的极化效应、隧道效应和渗流导电。当炭黑掺量在渗滤区以前时,极化效应占主导地位;当炭黑掺量在渗流区内时,隧道效应占主导地位,试件体现出明显的压敏性;当炭黑掺量继续增加时,炭黑聚集体接触的渗流导电占主导地位。更多还原

【Abstract】 Conductive carbon black(CB) with a particle diameter of about 33 nm was used to prepare smart concrete.Compared with carbon fibers,CB was much cheaper.And the content of CB in cement-matrix nanocomposites was nearly to that of carbon fibers.Results showed that the percolation threshold zone of the composites was CB in the amount of 0.6%—1.5%.A clear piezo-resistive effect of electrical resistance dependence on uniaxial compression deformation was observed in composites with different contents of CB,indicating that this type of smart nanocomposite was a promising candidate for strain sensing.Tunneling effect theory and percolation theory were employed to interpret the electromechanical effect of CB-filled cement-matrix composites.更多还原