In this review, the research reports on the dispersion processes of carbon nanotubes (CNTs) in aqueous cementitious materials are intensively introduced and summarized. The main processes for the CNTs dispersion in aqueous systems include high shear emulsification, ultrasonic treatment, covalent modification, and non-covalent modification. The influences of various factors on the dispersity of CNTs are evaluated, and the pros and cons of dispersion processes of CNTs are analyzed, along with the dispersion mechanism of CNTs in aqueous materials. Several novel techniques are also introduced, including arc thermal excitation and electromagnetic field-induced method, etc. In addition, the challenges when CNTs dispersion are further involved in cementitious alkali pore solution and the improvement means are also described in detail. And, the direct dispersion process (in situ growth process) of CNTs in cementitious materials has also been discussed in depth.

Carbon nanotubes (CNTs) reinforced cementitious composite (CNRC) with excellent electrical and self-sensing properties, which enables it to serve as an intrinsic sensor for structural health monitoring (SHM). However, the requirements of modern industry for accurate calculation and performance design of engineering materials are not met by traditional experimental studies alone. The finite element method (FEM) has the advantages of simplicity of operation, accuracy, and cost-effectiveness, and it has been widely used in the property verification and prediction of various composite materials. In this article, the constitutive model, FEM modeling method, and simulation process of CNRC along with existing model types, innate relations, and model parameters are reviewed, and the corresponding mechanical, electrical, and electromechanical coupling properties of CNRC under different parameters are systematically analyzed by FEM method. By combining different uncertainty parameters and model types, the advantages and disadvantages of FEM for mechanical, electromechanical coupling, and SHM applications of CNRC modeling are explored. The results are in good agreement with those in the existing CNRC experiment, which effectively proves the reliability of the FEM method in CNRC research. This work is important to develop a sound theoretical model verification and performance prediction for early applications in SHM of CNRC.

Strain sensors are essential for health monitoring of complex-shaped structures. Here, carbon nanotube thin films (CNTFS) with different double-layers were fabricated on a flexible polyethylene terephthalate substrate using layer-by-layer self-assembly technique, and their resistance behaviors and piezoresistive sensing performances were comprehensively conducted. Results show that the assembled layers of CNTFS are evenly and compactly deposited with about 7–15 μm, and the resistance decreases with the increase in the assembly layer number. The piezoresistive sensing behavior increases first and then decreases with the increase in the number of assembly layers along with compression or tension cyclic loading; the nine-double-layer CNTFS shows the best linearity, sensitivity, hysterics, and repeatability of 3.22%, 0.12684/mm, 2.16%, and 3.06%, respectively.