In recent years, carbon nanotubes (CNTs) incorporated smart cement composites have attracted significant attention as it opens up a new avenue to develop new class of sensors, in general, and uniquely enables the structural materials to reflect the internal stress state, in particular. However, dispersion of CNTs, threshold limit, polarization effect, type and design of electrode, effect of functionalization of CNTs etc. on piezo-resistive properties of cementitious nanocomposites need further investigations. The present study describes the systematic approach for developing cement based smart nanocomposites exploiting the unique capabilities of functionalised MWCNTs and comprehensive studies on performance under monotonic- and long reverse cyclic-loading. Three different types of multiwalled carbon nanotubes (MWCNTs) like pristine MWCNTs, hydroxyl (-OH) MWCNTs and carboxyl acid (-COOH) MWCNTs are considered. The response of cement based smart nanocomposites under cyclic compression load was measured in terms of fractional change in resistivity (FCR) where type and dosage of CNT, type of electrode are the parameters. The test results indicate that the performance of the smart composite with COOH-MWCNTs is superior compared to other types and the gauge factor of the composite is found to be as high as 451. The study also emphasizes the role of stabilization, tunneling effects and formation of conductive paths in imparting the piezo-resistive properties in porous, nonconductive materials like cement composites.

近年来，掺入碳纳米管（CNTs）的智能水泥复合材料引起了广泛的关注，因为它通常为开发新型传感器开辟了一条新途径，并且独特地使结构材料尤其能够反映内部应力状态。然而，碳纳米管的分散，阈值极限，极化效应，电极的类型和设计，碳纳米管的功能化等对胶结纳米复合材料压阻性能的影响还需要进一步研究。本研究描述了利用功能化MWCNT的独特功能开发水泥基智能纳米复合材料的系统方法，以及在单调和长反向循环载荷下的性能综合研究。三种不同类型的多壁碳纳米管（MWCNT），例如原始MWCNT，考虑了羟基（-OH）MWCNT和羧酸（-COOH）MWCNT。水泥基智能纳米复合材料在循环压缩载荷下的响应以电阻率的分数变化（FCR）进行测量，其中CNT的类型和剂量，电极的类型为参数。测试结果表明，具有COOH-MWCNTs的智能复合材料的性能优于其他类型，并且复合材料的规格系数高达451。该研究还强调了稳定作用，隧穿效应和形成的作用。导电路径在诸如水泥复合材料的多孔非导电材料中赋予压阻特性的过程中。水泥基智能纳米复合材料在循环压缩载荷下的响应以电阻率的分数变化（FCR）进行测量，其中CNT的类型和剂量，电极的类型为参数。测试结果表明，具有COOH-MWCNTs的智能复合材料的性能优于其他类型，并且复合材料的规格系数高达451。该研究还强调了稳定作用，隧穿效应和形成的作用。导电路径在赋予多孔非导电材料（如水泥复合材料）的压阻特性方面发挥重要作用。水泥基智能纳米复合材料在循环压缩载荷下的响应以电阻率的分数变化（FCR）进行测量，其中CNT的类型和剂量，电极的类型为参数。测试结果表明，具有COOH-MWCNTs的智能复合材料的性能优于其他类型，并且复合材料的规格系数高达451。该研究还强调了稳定作用，隧穿效应和形成的作用。导电路径在诸如水泥复合材料的多孔非导电材料中赋予压阻特性的过程中。