Preparation and Smart Properties of Carboxylated Carbon Nanotube Reinforced Cement-Based Composites

This study investigated the influence of the outer diameter of carboxylated carbon nanotubes (CNTs)on the electrical conductivity and piezoresistive characteristics of cement-based composites. Specimens incorporating CNTs of varying outer diameters were prepared using ultrasonic dispersion technology. Under a constant pressure of 10 MPa, the relationship curve between CNT outer diameter and the rate of resistivity variation was analyzed, revealing that the composite's state governs its piezoresistive response characteristics. The experimental results demonstrate that the outer diameter of the CNTs significantly affects the stability of both the electrical resistance and the piezoresistive performance of the composites. When the CNT outer diameter falls within the range of 25-35 nm, the material exhibits optimal comprehensive performance, achieving both a stable conductive network and high-sensitivity piezoresistive response simultaneously.