Editorial on Future Civil Engineering: Low Carbon, High Performance, and Strong Durability

1. Introduction

The global transition towards a green and low-carbon economy has catalyzed an unprecedented transformation in civil engineering [1,2,3,4]. Against a backdrop of increasing resource constraints and environmental concerns, the stability [5,6] and durability [7,8] of infrastructure will be seriously affected. Innovations and modifications in engineering materials and structures have garnered substantial research attention in recent years to address these challenges and advance sustainable development in civil engineering [9,10,11]. The 11 papers introduced in this paper covered several key areas, including non-destructive testing, smart building technologies, structural performance optimization, and post-disaster repair. Collectively, these studies clarify integrated approaches that reconcile engineering efficiency, environmental stewardship, and long-term durability. Ultimately, these efforts will drive the civil engineering industry towards a green and low-carbon perspective, improving intelligence and operational efficiency.

2. Overview of Contributions

Cheng et al. (contribution 1) investigated the effect of surface conditions on thermal contrast (ΔT) to ensure the effectiveness of the developed thermal contrast nondestructive testing (NDT) technique for the quantification of delamination in concrete structures. Three typical scenarios were presented based on the experimental results to establish the association of δT with delamination detection. Finally, a new approach to quantify the delamination of concrete structures at different time windows was proposed.

Based on Citespace software (version 6.2R4), Dong et al. (contribution 2) performed visualization and analysis of 2947 documents related to construction robots sourced from the CNKI Chinese database and WOS Core database. The summary results emphasized the critical role and importance of construction robots as an essential tool for intelligently upgrading the construction industry. Additionally, it was pointed out that future trends in the field would likely favor human–robot collaboration, intelligent construction, and robotic vision technologies.

A detailed numerical model of steel–UHPC composite slabs was developed by Li et al. (contribution 3), based on previous flexural behavior research, to clarify their flexural failure mechanism. Combined with the results of numerical simulation analyses, the formula, with high accuracy for calculating the flexural load capacity of steel–UHPC composite slabs under positive and negative bending moments, was proposed. The results provide theoretical guidance for the design of the flexural performance of steel–UHPC composite slabs.

The accuracy of detection for steel tube concrete de-bonding phenomena via infrared thermography based on heat excitation was ensured by Cai et al. (contribution 4), who first introduced spray cooling as an excitation method during the exothermic hydration stage. A systematic analysis of 39 groups of indoor concrete-filled steel tube (CFST) models was carried out by considering variables such as the atomization level, excitation distance, excitation duration, and water temperature in the tank. Finally, an efficient and stable cooling excitation method applicable to engineering detection was proposed.

Zhao et al. (contribution 5) systematically studied the influence mechanism of vibration loads on the flexural performance of ultra-high-performance concrete (UHPC) wet joints by using four-point flexural experiments combined with theoretical analyses. The results showed that low-amplitude or low-frequency vibrations would increase the flexural strength of UHPC wet joints. Meanwhile, a model for the calculation of flexural strength considering vibration parameters was developed. The flexural strength obtained using the proposed model agreed very well with the experimental observations, demonstrating the validity of the model.

To address the challenge of the insufficient load-carrying capacity of existing structures, Zhu et al. (contribution 6) investigated the strengthening technique of high-strength steel wire mesh and UHPC through axial tensile tests, constitutive modeling, and finite element analysis. The effects of the steel fiber volume ratio and high-tensile wire mesh strengthening ratio on the axial tensile performance of reinforced concrete (RC) beams were clarified. In addition, the influence of key parameters on the strengthening effect of RC beams was analyzed using finite elements, and an optimized combination of strengthening parameters was proposed.

Du et al. (contribution 7) investigated the flexural performance of retard-bonded prestressed ultra-high-performance concrete (RBPU) beams under various reinforcement ratios through experimental studies and theoretical analyses. The results showed that the cracking moment, ultimate moment, and ductility coefficient of RBPU beams increased significantly as the reinforcement ratio increased. This study also established a calculation method for the cracking bending moment and ultimate bending moment of RBPU beams and introduced a correction factor to improve the calculation accuracy.

To address the effect of ground fissure dislocations on the bottom void range of underground pipe gallery structures, Yu et al. (contribution 8) proposed an innovative analytical method and revealed critical mechanical regulations through a combination of theoretical modeling and experiments. The hyperbolic tangent function was used to quantitatively describe the nonlinear relationship between the end displacement of the hanging wall pipe corridor structure (Δ₁) and the dislocation of the ground fissure (Δ₂). In addition, the prediction of the bottom void range was achieved by solving the static equilibrium equations in MATLAB R2022a programming.

Ran et al. (contribution 9) proposed an innovative active underpinning technology that integrates a ‘井’-shaped cap system, graded preloading of the foundation, and synchronous beam body correction to repair the concrete box girder bridge piers in mountainous highways that were damaged by falling rocks. The safety and effectiveness of the repaired bridge structure were verified through numerical simulation, dynamic monitoring, and load testing. This technology provides an effective solution for the fast and safe repair of damaged bridge piers, which is essential for improving the disaster resistance and emergency response speed of bridge projects.

A dynamic prediction model based on the gray system theory was proposed by Ma et al. (contribution 10). By combining the GM (1,1) gray model with the variable-size sliding window technique, the model could dynamically update the latest monitoring data and significantly improve the prediction accuracy. The study also innovatively designed two data preprocessing mechanisms, i.e., equidistant and exponential. The model was validated at Kansai International Airport and Xiamen Xiang’an International Airport with an over 20% improvement in accuracy compared to the traditional gray method.

Using on-site examination, testing, and numerical simulation, Yang et al. (contribution 11) systematically analyzed the damage mechanism in the concrete components of a high-pile beam plate wharf. A full-scale 3D numerical model containing 40 rows of beams, 204 columns, and complex foundations was innovatively constructed. A high degree of consistency between the plastic damage distribution and the actual crack location was demonstrated by the model. Based on the analysis results, a graded crack repair strategy and load optimization scheme were proposed.

3. Conclusions

This Special Issue presents 11 groundbreaking research studies on the innovation and transformation of civil engineering materials and structures. The insights presented are expected to drive further progress and inspire future research in the field of civil engineering.