Owing to its outstanding sensing properties, mechanical properties, and durability, self-monitoring carbon nanotube (CNT) cementitious composite can serve as an intrinsic smart sensor for structural health monitoring and traffic detection. However, it is not clear at present what the origin of the sensing property of the self-monitoring CNT cementitious composite is. This paper discusses the nature of the sensing property of the composite measured with dc and ac circuits based on a commonly used conductive model of CNT cementitious composite and reveals the origin of the sensing property of the composite through experiments. Experimental results indicate that the sensing property of the composite mainly results from the change in contact resistance between adjacent CNTs under external force or deformation.
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