关键词：
bridge risk;analytic hierarchy;entropy weight method;grey fuzzy theory
摘要：
Bridge safety during operating periods is a primary concern worldwide, and the evaluation of bridge risks is a critical aspect of ensuring bridge safety. The most common methods used for bridge risk evaluations include fuzzy comprehensive evaluations, grey system theory, fault tree analysis, the Kent index method, and data envelopment analysis. However, these approaches are highly subjective and have uneven distributions when determining the weights of risk indicators. To improve the accuracy and feasibility of bridge risk evaluations for a given period of operation, we first establish bridge risk indicators and assign subjective weights to each indicator based on an analytic hierarchy process. Additionally, objective weights are assigned to each indicator according to an entropy weighting method. Then, the combined weights of each risk indicator are obtained by applying game theory principles. This enables the construction of a degree of membership matrix comprising these risk indicators, which is established according to an expert grading method and grey fuzzy theory. Finally, the evaluation results vector is calculated, allowing the risk level of a bridge to be assessed according to the principle of the maximum degree of membership. Overall, this study provides a more accurate and objective method for evaluating bridge risk during a given period of operation.
摘要：
Abstract: The accumulation of steel slag and other industrial solid wastes has caused serious environmental pollution and resource waste, and the resource utilization of steel slag is imminent. In this paper, alkali-activated ultra-high-performance concrete (AAM-UHPC) was prepared by replacing ground granulated blast furnace slag (GGBFS) powder with different proportions of steel slag powder, and its workability, mechanical properties, curing condition, microstructure, and pore structure were investigated. The results illustrate that the incorporation of steel slag powder can significantly delay the setting time and improve the flowability of AAM-UHPC, making it possible for engineering applications. The mechanical properties of AAM-UHPC showed a tendency to increase and then decrease with the increase in steel slag dosing and reached their best performance at a 30% dosage of steel slag. The maximum compressive strength and flexural strength are 157.1 MPa and 16.32 Mpa, respectively. High-temperature steam or hot water curing at an early age was beneficial to the strength development of AAM-UHPC, but continuous high-temperature, hot, and humid curing would lead to strength inversion. When the dosage of steel slag is 30%, the average pore diameter of the matrix is only 8.43 nm, and the appropriate steel slag dosage can reduce the heat of hydration and refine the pore size distribution, making the matrix denser. Keywords: ultra-high-performance concrete; steel slag powder; alkali activated materials; curing condition; microstructure
摘要：
With the acceleration of the construction of sponge cities in China, porous asphalt pavement (PA) is has been widely used. High-viscosity asphalt (HVA) is the core material in building PA because it has good rheology properties, which can provide good raveling and rutting resistance. However, due to the open-graded structure of PA, HVA was more susceptible to rapid aging, which significantly affects the durability of PA. To investigate the thermal aging effect on the rheological properties of self-modified HVA (SHVA), five types of asphalts were aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV). Then, rheological tests were adopted, such as temperature sweep test (TS), repeated creep and recovery test (RCR), and bending beam rheometer test (BBR). The results indicate that during the aging process, the oxidation-induced hardening effect of neat asphalt and the degradation-induced softening effect of the modifier changes the rheology properties of HVA significantly. As the aging progresses, the contribution of the modifiers of HVA to anti-aging performance is greatly reduced. At high temperatures, HVA demonstrates better anti-aging performance than conventional styrene-butadiene-styrene (SBS)-modified asphalt (Guo Chuang, GC). The change of the high-temperature rheological indices of the two HVA types (SHVA and TAFPACK-super HVA (TPS)) showed a smaller activation energy index (EAI), a more considerable viscous component of binder creep stiffness (Gv), and more minor accumulated stain (r(acc)), indicating a more significant anti-short-term and long-term aging performance, which is beneficial to the high-temperature performance of asphalts. However, the changes in low-temperature rheological properties do not align with those in high-temperature rheological properties after long-term aging. The BBR test results reveal that TPS exhibits worse low-temperature performance than GC and SHVA. During the thermal aging process, the contribution rate of the modifiers in SHVA against RTFO and PAV aging is higher than that of the modifiers in TPS, which contributes to the superior anti-aging property. Overall, SHVA demonstrates the best anti-aging performance among the five asphalts tested.
摘要：
Consolidated undrained triaxial shear tests were performed on undisturbed saturated structured clay at three unloading rates (0.1, 0.25, and 2.5 kPa/min) using a GDS triaxial system to determine the effects of different unloading rates and unloading stress paths on the stress-strain relationship, pore pressure variation, and failure strength characteristics of Zhanjiang structured clay. Microstructural changes in the clay were observed during shear tests at different unloading rates. Furthermore, the obtained stress-strain relationship indicates strain-softening under different unloading stress paths. Under the same axial strain, a larger unloading rate caused a larger deviatoric stress. Under the same conditions, the higher the confining pressure, the greater the peak pore pressure, the smaller the unloading rate, the greater the pore pressure development, and the greater the variation in the pore pressure. Moreover, the undrained shear strength increased with an increase in the unloading rate from 0.1 to 2.5 kPa/min. The change in the unloading rate had a greater effect on the undrained strength under the passive tensile path than that under the passive compression path. The microstructure of the Zhanjiang structured clay changed after shear tests at different unloading rates, exhibiting various degrees of adjustment in the particle arrangement, contact relations, pore sizes, and shapes.
作者机构：
[Huang, Chuyue; Wu, Jie] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Huang, Yule; Huang, Shiping; He, Yongjin; Eslamlou, Armin Dadras; Huang, SP] South China Univ Technol, Sch Civil Engn & Transportat, Guangzhou 510640, Peoples R China.;[Xu, Chengyu; Jia, Xiaoping] China Railway 17th Bur Grp Guangzhou Co Ltd, Guangzhou 510799, Peoples R China.;[Chen, Qianru] South China Normal Univ, Sch Elect & Informat Engn, Foshan 528225, Peoples R China.
通讯机构：
[Chen, QR ; Huang, SP ] S;South China Univ Technol, Sch Civil Engn & Transportat, Guangzhou 510640, Peoples R China.;South China Normal Univ, Sch Elect & Informat Engn, Foshan 528225, Peoples R China.
关键词：
structural health monitoring;crack detection;interpretability analysis;convolutional neural network
摘要：
Crack detection is an important task in bridge health monitoring, and related detection methods have gradually shifted from traditional manual methods to intelligent approaches with convolutional neural networks (CNNs) in recent years. Due to the opaque process of training and operating CNNs, if the learned features for identifying cracks in the network are not evaluated, it may lead to safety risks. In this study, to evaluate the recognition basis of different crack detection networks; several crack detection CNNs are trained using the same training conditions. Afterwards, several crack images are used to construct a dataset, which are used to interpret and analyze the trained networks and obtain the learned features for identifying cracks. Additionally, a crack identification performance criterion based on interpretability analysis is proposed. Finally, a training framework is introduced based on the issues reflected in the interpretability analysis.
关键词：
Building energy conservation;Composite phase change material;Calcium chloride hexahydrate;Silica aerogel
摘要：
To meet the national demand for energy conservation and emission reduction, a shape-stable CaCl(2)(.)6H(2)O /silica aerogel composite phase change material (CPCM) for building energy storage was successfully developed. The CPCM was formed by using modified CaCl(2)(.)6H(2)O composed of CaCl(2)(.)6H(2)O (main PCM) and SrCl(2)(.)6H(2)O (nucleating agent) as PCM, and silica aerogel as carrier via physical blending method. The structure and prop-erties of the CPCM were investigated by various techniques. The results showed that compositing of modified CaCl(2)(.)6H(2)O with silica aerogel could significantly reduce the thermal conductivity, effectively prevent leakage as well as lessen supercooling. The obtained CPCM with 75 wt% modified CaCl(2)(.)6H(2)O had suitable phase transition temperature (27.0 degrees C) with high latent heat (110.9 J(.)g(-1)), acceptable supercooling degree (1.6 degrees C), low thermal conductivity (0.1954 W/(m(.)K)) as well as excellent thermal reliability. The results obtained make the CPCM in this work promising for use in building thermal insulation materials.
作者机构：
[Jiang, Xiaohuan; Xu, Hao; Li, Jialiang; Ma, Yuxi] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Xu, Hao; Cheng, Fei] China Univ Geosci, Hubei Key Lab Marine Geol Resources, Wuhan 430074, Peoples R China.;[Yu, Xinjiang] Changjiang River Sci Res Inst, Minist Water Resources, Res Ctr Water Engn Safety & Disaster Prevent, Wuhan 430010, Peoples R China.
通讯机构：
[Fei Cheng] H;Hubei Key Laboratory of Marine Geological Resources, China University of Geosciences, Wuhan 430074, China<&wdkj&>Author to whom correspondence should be addressed.
