Graphene (G) and graphene oxide (GO) have been shown to significantly improve the mechanical properties of cement-based materials. In this study, the effect of the G/GO on cement hydration was investigated. First, the zeta potential of G/GO in simulated solutions was tested, and the interaction between G/GO’s surface and Ca ²⁺ was explored. Subsequently, scanning electron microscopy was used to observe the morphology of C–S–H nucleation and growth on the cement surface in the cement paste containing G/GO. Furthermore, XRD and TGA analyses were carried out on the hydration products of the sample. At last, isothermal calorimetry was applied to investigate the influence of G/GO on the early hydration of cement. The results showed that the addition of G/GO significantly accelerates C–S–H nucleation and growth on the cement surface. It is indicated that the high mobility ions derived by G/GO in the cement paste dominate the reason for the accelerated hydration of cement. The presence of G, especially GO, facilitates the mobility of ions, especially Ca ²⁺ , thus enhances the interaction between the cement surface and the ions. This strong interaction promotes the C–S–H nucleation and growth, and therefore, the hydration of the cement.

In last few years, big data and deep learning technologies have been successfully applied in various fields of civil engineering with the great progress of machine learning techniques. However, until now, there has been no comprehensive review on its applications in civil engineering. To fill this gap, this paper reviews the application and development of artificial intelligence in civil engineering in recent years, including intelligent algorithms, big data and deep learning. Through the work of this paper, the research direction and difficulties of artificial intelligence in civil engineering for the past few years can be known. It is shown that the studies of artificial intelligence in civil engineering mainly focus on structural maintenance and management, and the design optimization.

In this paper, unified practical formulas are proposed to estimate cable tension for vibrations under different boundaries. Correction coefficients are applied to the cable tensions calculated from the taut string theory. In these formulas, a dimensionless parameter η is introduced to represent the relative bending stiffness of the cable in lieu of the dimensionless parameter ξ in the previous formulas found in practice. Results have shown that the proposed formulas are accurate. For the fixed-fixed boundaries, the error in the estimated cable tensions for various frequencies is less than 3% for η ≤ 0.88, and less than 1% for η ≤ 0.55. For the fixed-hinged boundaries, the error in the estimated cable tensions for various frequencies is less than 1% for η ≤ 0.9. If there are multiple frequencies in the in-situ measurement, the proposed formulas can be used to identify the cable tension and bending stiffness simultaneously by solving a quadratic equation. The proposed formulas have been validated against several numerical examples as well as practical test cases.

The buckling behavior of functionally graded graphene platelet-reinforced composite (FG-GPLRC) shallow arches with elastic rotational constraints under uniform radial load is investigated in this paper. The nonlinear equilibrium equation of the FG-GPLRC shallow arch with elastic rotational constraints under uniform radial load is established using the Halpin-Tsai micromechanics model and the principle of virtual work, from which the critical buckling load of FG-GPLRC shallow arches with elastic rotational constraints can be obtained. This paper gives special attention to the effect of the GPL distribution pattern, weight fraction, geometric parameters, and the constraint stiffness on the buckling load. The numerical results show that all of the FG-GPLRC shallow arches with elastic rotational constraints have a higher buckling load-carrying capacity compared to the pure epoxy arch, and arches of the distribution pattern X have the highest buckling load among four distribution patterns. When the GPL weight fraction is constant, the thinner and larger GPL can provide the better reinforcing effect to the FG-GPLRC shallow arch. However, when the value of the aspect ratio is greater than 4, the flakiness ratio is greater than 103, and the effect of GPL’s dimensions on the buckling load of the FG-GPLRC shallow arch is less significant. In addition, the buckling model of FG-GPLRC shallow arch with elastic rotational constraints is changed as the GPL distribution patterns or the constraint stiffness changes. It is expected that the method and the results that are presented in this paper will be useful as a reference for the stability design of this type of arch in the future.

Fiber-reinforced polymer composites are high-performance materials used extensively in aerospace and defense industries. Researchers have added various nanoscale materials to FRPs for improving their mechanical properties and to prepare multifunctional composites. Carbon nanotubes (CNTs) with their high strength, high modulus, and large aspect ratio have emerged as a frontrunner in the nano-reinforcements, and there is a large volume of published research on this topic. This article provides an extensive review of key publications covering topics of fabrication methods, enhancement of mechanical properties, and applications of CNT-modified FRP materials in structural health monitoring. A description of the main methods of adding CNTs into FRP materials, including dispersion in the resin and film lay-up, is presented. A key focus of the review is the effect of CNTs on the mechanical properties of FRP composites, including interlaminar fracture toughness, impact resistance, and fatigue properties. Since CNTs have self-sensing properties, there is potential to use CNTs for nondestructive identification (NDI) and structural health monitoring (SHM) of composite structures. Finally, a discussion of the problems that might be encountered during the use of CNTs as nano-reinforcements in FRP, and the future application potential of CNT-modified FRP materials is reported.