作者：
Wang, Xinzhong;Li, Linshu;Xiang, Yi;Wu, Yuexing;Wei, Mei
期刊：
Frontiers in Materials,2024年10 ISSN：2296-8016
通讯作者：
Wang, XZ
作者机构：
[Li, Linshu; Wang, XZ; Wang, Xinzhong; Wu, Yuexing; Xiang, Yi] Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.;[Wei, Mei] Hunan Arts & Crafts Vocat Coll, Sch Digital Arts, Yiyang, Peoples R China.
通讯机构：
[Wang, XZ ] H;Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.
关键词：
concrete-filled steel tube;basalt fiber;short columns;finite element analysis;bearing capacity;ductility coefficient
摘要：
With rapid economic and social development, both concrete-filled steel tube (CFST) composite structures and basalt fiber (BF) have been widely applied in the field of civil engineering. To investigate the laws and characteristics of the influence of chopped BF on the mechanical properties of CFST columns and further promote the application of BF in CFST structures, the axial compressive bearing capacity test of 18 CFST short columns was carried out, and the influence of BF of different lengths on their structural mechanical properties was analyzed. The test results were compared with the theoretical calculation results and the finite element analysis results to verify the reasonableness of the test results. The results reveal that the axial compressive bearing capacity of the CFST short column after adding BF is significantly improved compared to the ordinary CFST short column, in which the bearing capacity and the ductility coefficient are increased by approximately 8.1% and 31.6%, respectively, on average. In addition, changing the length of BF has less effect on the bearing capacity of CFST short columns, the rate of increase in bearing capacity decreases with an increase in the steel ratio of CFST, and the coefficient of ductility increases with the increase in the steel ratio.
关键词：
Asphalt mixture;Mesoscopic analysis;Skeleton evolution;Aggregate contact;Particle movement;Discrete element method
摘要：
The aggregate skeleton is the intrinsic core of asphalt mixtures for load transfer, which is quite different under various gradations. For evaluating the loading characteristics of the aggregate skeleton, this research combined the 3D blue -ray scanning technology and discrete element method (DEM) to establish the numerical models of different graded asphalt mixtures considering the real aggregate morphology. A linear parallel bond model was used to simulate the adhesion effect of asphalt, and the uniaxial compression numerical simulation was verified by indoor tests. In addition, the contact force, contact number, anisotropy, and rotation angle were used to evaluate the aggregate skeleton evolution under uniaxial compression loading. Furthermore, the contribution of each grade aggregate in the gradation to the skeleton structure was analyzed. Results show that the average contact force is higher in large -size aggregates above 9.5 mm, which exhibit greater load transfer efficiency. Moreover, 4.75-9.5 mm size aggregates combine the functions of bearing and filling, and its role is significantly affected by the gradation. It is also found that the internal skeleton structure can be optimized and adjusted under stress. The contact numbers of different graded mixtures follow a close decrease, and the strong contacts are mostly provided by coarse aggregates above 4.75 mm. The anisotropy development of aggregate skeleton contact force is induced by the stress, and the deviator fabric of asphalt mixtures show a good linear positive correlation with the uniaxial compressive strength (UCS). Besides, fine aggregates exhibit greater cumulative rotation angle and instability effect, it is feasible to detect asphalt mixture deformation by the rotation angle of particles.
作者：
Ming Xiao*;Lihua Chen;Haoxiong Feng;Zhigao Peng;Qiong Long
期刊：
Archives of Computational Methods in Engineering,2024年:1-25 ISSN：1134-3060
通讯作者：
Ming Xiao
作者机构：
[Ming Xiao; Lihua Chen; Haoxiong Feng; Zhigao Peng; Qiong Long] College of Civil Engineering, Hunan City University, Yiyang, China
通讯机构：
[Ming Xiao] C;College of Civil Engineering, Hunan City University, Yiyang, China
摘要：
This paper investigates the implementation of a Multi-Objective Optimization technique for improving public transportation route planning in the setting of smart cities. Recognizing the difficulties of urban mobility, our technique incorporates a variety of criteria, including traffic patterns, cost-effectiveness, and environmental impact, to create an efficient route design system. The research applies complex algorithms to overcome the issues present in existing route planning procedures, using real-world data sources such as GPS data and traffic reports. We illustrate the efficacy of our strategy in boosting time efficiency, lowering costs, and decreasing environmental footprints via extensive case studies. The assessment measures used emphasise the suggested system’s advantages over current techniques. The debate digs into the larger implications for smart city development, recognising limits and providing possibilities for further study. This study adds vital insights and practical answers to the developing subject of smart city transportation, providing a solid basis for the continuing growth of urban mobility.
通讯机构：
[Zhang, L ] H;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;Hunan Univ Technol, Hunan Engn Res Ctr Struct Safety & Disaster Preven, Yiyang 413000, Peoples R China.
关键词：
boulder and hard rock environment;GPR;wavelet scale energy spectrum;wavelet packet energy;time-frequency characteristics
摘要：
The hard rocks in the stratum can pose safety risks and hinder the progress of urban underground tunnel construction using shield and jacking methods, thereby reducing construction efficiency and increasing construction costs. This paper utilizes wavelet scale energy spectrum, wavelet packet theory and statistical methods to conduct research on the detection of special geological formations such as hard rocks and voids, as well as the analysis of their signal time-frequency characteristics based on the ground-penetrating radar (GPR) technique. On the basis of calibrating the permittivity of different types of rock blocks, we established a forward model for detecting hard rocks and voids, and the simulated signals were analyzed in the time and frequency domains. Subsequently, laboratory experiments were conducted to perform GPR tests on different types of hard rocks in natural and water-saturated states and voids, to explore the time-frequency characteristics, frequency band energy variations, and statistical patterns of typical single-trace signals. The results show that the granite detection signal contains more low-frequency components, the sandstone detection signal contains more medium-low frequency components, while the limestone detection signal contains more medium-high frequency components in their natural state; the signal from the karst cave has relatively more low-frequency components than the signal from the empty cavity. The geometric shape of the rock has no influence on the dominant frequency and time-frequency distribution of its reflection signal. Generally, rocks with higher rebound values (hardness) also exhibit larger variance and standard deviation in frequency band energy. The research has important theoretical significance and practical value for the measurement and assessment of special geological features such as hard rocks and voids in urban underground trenchless construction.
作者：
Wan Dai;Guoping Qian;Xuan Zhu;Huanan Yu*;Changyun Shi;...
期刊：
Construction and Building Materials,2024年416:135069 ISSN：0950-0618
通讯作者：
Huanan Yu
作者机构：
[Wan Dai; Changyun Shi; Chao Zhang; Jinguo Ge; Tangxin Xie] School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China;Xiangjiang Laboratory, Changsha 410205, China;National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China;School of Civil Engineering, Hunan City University, Yiyang 413000, China;[Guoping Qian; Huanan Yu] School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Xiangjiang Laboratory, Changsha 410205, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China
通讯机构：
[Huanan Yu] S;School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Xiangjiang Laboratory, Changsha 410205, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China
摘要：
Void is an important manifestation of the strength of asphalt mixture, but few studies have focused on the change of voids during the compaction of asphalt mixtures. The voids of SMA-13 and OGFC-13 were selected as the research objects, and the compaction process of the asphalt mixture was analyzed based on different compaction degree specimens in lab through gyratory compactor. Firstly, CT scanning was used to extract the void structure of the asphalt mixture at different degrees. Secondly, based on the 26-connectivity algorithm, the connected voids and closed voids of asphalt mixture were extracted, and the volume and particle size distribution were analyzed. Thirdly, the gradation of voids was analyzed by the two-parameter Weibull function, and the morphological characteristics of voids were analyzed by roundness, sphericity, and abundance. The results showed that the distribution of cross-section voids ratio and the number of voids of the SMA-13 was more uniform than that of OGFC-13. The characteristic parameters of two-parameter Weibull function showed that with the increase of specimen density, the three-dimensional void size became smaller and smaller, and the void size distribution became more and more uniform. The sphericity and roundness of the voids of SMA-13 and OGFC-13 were less affected by the compaction degree, and the void abundance of the OGFC-13 gradation asphalt mixture was greatly affected. For the connectivity of voids, the closed void volume of OGFC-13 increased with the increase of compaction degree, but the maximum proportion of closed voids in the total void volume does not exceed 10% during the compaction process. For the gradation SMA-13, the compaction degree of 90%∼93% was the boundary interval of connected voids from existence to nonexistence, which may be a critical interval for forming skeleton strength during the compaction process.
作者机构：
[Zhengyang Li; Zhengdong Luo] College of Civil Engineering, Xiangtan University, Xiangtan 411105, China;Authors to whom correspondence should be addressed.;[Huichen Yang] China Institute of Water Resources and Hydropower Research, Beijing 100041, China;[Genbao Zhang] College of Civil Engineering, Hunan City University, Yiyang 413000, China;[Kun Liu] Hunan Zhitong Expressway Construction and Development Co., Ltd., Changsha 410026, China
通讯机构：
[Benben Zhang; Yufei Zhao] A;Authors to whom correspondence should be addressed.<&wdkj&>China Institute of Water Resources and Hydropower Research, Beijing 100041, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>School of Transportation, Southeast University, Nanjing 211189, China
关键词：
interfacial behavior;slag;fly ash and red mud;geopolymer mortar;concrete substrate;mechanical properties
摘要：
Geopolymer, as a new type of solid waste-based inorganic cementitious material, exhibits outstanding behavior in terms of physical and chemical performance, macromechanical properties, long-lasting stability, and features potential application development tendency in the field of repair and reinforcement of existing concrete structures. This paper investigated the interfacial behavior of geopolymer mortar with OPC concrete substrate under different slag, fly ash and red mud mixing proportions, while cement mortar was used as a control group for the research. The interfacial bonding properties of the geopolymer mortar to the OPC concrete substrate were elaborated by carrying out split tensile test, double-sided shear test, and three-point bending test. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to further analyze the microstructural characteristics and physical phase components of the interfacial transition zone between the geopolymer mortar and the OPC concrete substrate. The results indicated that the compressive strength of slag-fly ash-red mud-based geopolymer mortar under different mixing ratio conditions was consistently superior to that of cement mortar, where the optimum mixing ratio for the geopolymer mortar was S33F33R33. Overall, the interfacial bonding properties of the geopolymer mortar to the OPC concrete substrate gradually increased with the increment of the slag content, however, an evolutionary trend of minor enhancement followed by a gradual reduction was observed with the growth of the fly ash and red mud content.
期刊：
Bulletin of Engineering Geology and the Environment,2024年83(3):1-15 ISSN：1435-9529
通讯作者：
Hu, HX;Deng, C
作者机构：
[Xie, Zhongliang; Cai, Yuehui; Hu, Huanxiao; Lu, Yufan; Gan, Benqing] Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol E, Changsha 410083, Peoples R China.;[Xie, Zhongliang; Cai, Yuehui; Hu, Huanxiao; Lu, Yufan; Gan, Benqing] Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.;[Deng, Chao] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Deng, C ] H;[Hu, HX ] M;Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol E, Changsha 410083, Peoples R China.;Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.;Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.
摘要：
The grouting technique has been widely applied in geotechnical engineering. However, due to the concealed nature of underground engineering, there is relatively limited research on the diffusion characteristics of grout in sandy soil. This study utilized a self-developed three-dimensional grouting model test system. Experiments tests were conducted using standard sand and different water-cement (w/c) ratios of grout under limited boundary conditions, diffusion mechanism of sand soil grouting revealed. It was found that lower w/c ratios require higher grouting pressure when injecting grout into the sandy soil. The grouting pressure exhibited a pulsating pattern over time and a grouting pressure up to 323.9 kPa at w/c = 0.6. The grouting diffusion pattern under all w/c ratio conditions displayed typical columnar diffusion, and there was a good linear relationship between the average diffusion radius of the grout and the w/c ratio; the average diffusion radius was between 121 and 208 mm. The volume of the grout bulbs varied significantly at different w/c ratios, decreasing as the w/c ratio increased. With increased grouting pressure and w/c ratio, the dewatering effect during the grouting process became more pronounced, and the bleeding rate of the slurry with w/c = 1.4 (67.1%) is more than six times that of the w/c = 0.6 (10.5%). The results show that the uplift displacement on the soil surface exhibited certain hysteresis, and the grouting lifting process in sandy soil was divided into three stages: initial deformation, accelerated uplift, and stable uplift.
摘要：
To estimate the progressive collapse resistance capacity of a multi-column frame tube structure with an assembled truss beam composite floor (ATBCF), pushdown analysis and nonlinear dynamic analysis are conducted for such a structure using the alternate load path (ALP) method. The bearing capacities of the remaining structures under three different work conditions, which are the side middle column removal, the edge middle column removal, and the corner column removal, are individually studied, and the collapse mechanism of the remaining structures is analyzed based on the aspects of the internal force redistribution and the failure mode of the second defense line. Simultaneously, the influence of the column failure time on the dynamic response of the remaining structure and the dynamic amplification coefficient is discussed. The results indicate that the residual bearing capacity of the remaining structure following the bottom corner column removal is higher than that of the one following the side or edge middle column removal, while the latter has a stronger plastic deformation capacity. When the ALP method is adopted to operate the progressive collapse analysis, it is reasonable to take the column failure time as 0.1 times the period of the first-order vertical vibration mode of the remaining structure, and it is suitable to set the dynamic amplification coefficient as 2.0, which is the ratio of the maximum dynamic displacement to the static displacement of the remaining structure under the transient loading condition.
摘要：
The fatigue crack propagation behaviour of Q550E high-performance steel (HPS) is studied in this paper. Static tensile testing and fatigue crack propagation testing were carried out, and the results were compared with those of Q235. Finite element models were developed and verified against the experimental results. The impacts of the initial crack angle, crack depth ratio, stress ratio, thickness, and corrosion pitting on the fatigue crack propagation behaviour of the HPS were analysed. The results show that the fatigue life of Q550 was reduced by 18% due to the corrosion pitting, but it did not change the crack propagation path. When the stress intensity factor is higher than a certain value, the fatigue performance of Q235 is better than that of Q550E. The initial crack angle of 52.5 & DEG; is the critical angle of the crack stress intensity factor. The steel tends to fracture as the crack depth ratio increases, and more attention should be paid to the effective crack length in engineering practice. An increasing stress ratio leads to a smaller stress intensity factor, and the thickness affects the stress intensity factor in the later stage. The crack stress intensity factor around the corrosion pits gradually decreases along the thickness direction, and the crack tips around the corrosion pits tend to reach the yield state initially, accelerating the fatigue fracture of the specimen and ultimately leading to a decrease in fatigue life.
摘要：
Efflorescence is a concerning issue in geopolymer formulations. By accelerating efflorescence, the efflorescence behavior and compressive strength evolution were analyzed for metakaolin (MK)-based geopolymers cured at various temperatures and times. Mercury Intrusion Porosimetry (MIP) was the primary characterization method utilized in this study. Based on the pore structure, we identified the influence of pore structure on efflorescence behavior and compressive strength evolution. Those results showed that long-term and initial high-temperature curing played a negative role in mitigating efflorescence. Long-term curing refined the pore size, facilitating alkali salt migration to the surface. Initial high-temperature curing enhanced pore connectivity, which facilitated alkali salt movement. The number of pores below 20 nm governs the effect of efflorescence on compressive strength. Crystallization degrades geopolymer with a large number of pores below 20 nm. This study provides a new understanding of the effect of pore structure on efflorescence and the evolution of compressive strength during efflorescence and facilitates optimization of geopolymer formulations to relieve efflorescence.
通讯机构：
[Jianrong Cai] S;School of Civil Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Reversible lanes constitute an important solutions for sustainable transportation, with the aim to solve the practical problem of reversible lane optimization of urban road networks constrained by adjustment time. Considering the relationship between the number of lanes and the capacity of sections, a mixed-integer bilevel programming model of reversible lane optimization constrained by adjustment time is constructed in order to minimize the total travel time of the system. The results show that the model can effectively obtain the optimal strategy for any number of reversible sections subject to adjustment time constraints. With the increase of the number of reversible sections that can be optimized within the adjustment time, the cumulative reduced system time increases monotonically and the road network optimization effect improves, but as a whole, the optimization effect of the newly added reversible sections in each stage shows a decreasing trend. When the number of reversible sections that can be optimized within the adjustment time reaches a certain number, increasing the number of reversible sections will have a limited further effect on the overall system. For the reversible lane optimization problem of urban road networks, only efficient reversible sections need to be optimized to achieve a good optimization effect.
通讯机构：
[Sen Lin] S;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
作者机构：
[Luo, Xiaoyong; Long, Hao; Dong, Shuang; Luo, XY; Liu, Jinhong] Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;[Long, Hao] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Luo, Xiaoyong; Luo, XY] Cent South Univ, Hunan Prefabricated Bldg Engn Technol Res Ctr, Changsha 410000, Peoples R China.
通讯机构：
[Luo, XY ] C;Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;Cent South Univ, Hunan Prefabricated Bldg Engn Technol Res Ctr, Changsha 410000, Peoples R China.
关键词：
prefabricated components;tolerance;manufacturing dimensions;dimensional chain;monte carlo method;installation reliability
摘要：
During the installation process of prefabricated components, deviations in dimensions and installation positions can occur due to construction quality issues, and the accumulation of these deviations can impact the reliability of component installation. However, the current approach to addressing accumulated deviations in the component installation process primarily relies on the trial-and-error method, lacking a solid theoretical foundation. This paper introduces the dimensional chain theory derived from mechanical engineering and presents a method to evaluate the installation reliability of prefabricated components in concrete structures. First, based on extensive measurements of installation deviations, it was found that the installation deviations of components followed a log-normal distribution. By analyzing the relationship between installation deviations and the acceptance rate, it was determined that for a 90% acceptance rate, the installation position deviation should be 8.6 mm for prefabricated wall panel components and 7.3 mm for prefabricated column components. Subsequently, the concept of dimensional chain theory from mechanical engineering was introduced to establish a limit state equation for quantifying the installation reliability of prefabricated components in concrete structures. By applying this theory, appropriate component fabrication dimensions could be determined to achieve a 95% level of installation reliability. Finally, by using the Monte Carlo method to solve the installation limit state equation for an actual engineering project, recommended fabrication dimensions for the components were obtained. The results indicate that within the horizontal axis, the length deviation of prefabricated beams, and the width fabrication dimension of columns needed to be reduced by 2.3 mm to 2.9 mm. Within the vertical axis, the length dimension of columns and the height dimension of beams had to be reduced by 0.9 mm to 2.2 mm to achieve a 95% level of installation reliability.
期刊：
Advances in Civil Engineering,2023年2023 ISSN：1687-8086
通讯作者：
Wang, YK
作者机构：
[Wang, YK; Wang, Yukui; Zhang, Dan] Hunan City Univ, Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413099, Peoples R China.;[Yan, Shijun] Hunan City Univ, Coll Mech & Elect Engn, Yiyang 413000, Peoples R China.;[Zhang, Dan] Hunan City Univ, Key Lab Green Bldg & Intelligent Construct Higher, Yiyang 413000, Peoples R China.;[Hu, Zhangqi] Hunan City Univ, Coll Civil Engn, Yiyang 413099, Peoples R China.
通讯机构：
[Wang, YK ] H;Hunan City Univ, Hunan Engn Res Ctr Dev & Applicat Ceramsite Concre, Yiyang 413099, Peoples R China.
关键词：
Introduction;Materials and Methods;Results;Discussion;Conclusion;Abstract;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interests;Authors’ Contributions;Funding Statement;Acknowledgements;Acknowledgments;Supplementary Materials;Reference;Dataset Description;Dataset Files;Abstract;Introduction;Introduction and Materials;Introduction and Methods;Materials;Materials and Methods;Methods;Results;Discussion;Results and Discussion;Discussion and Conclusion;Results and Conclusion;Conclusion;Conclusions;Data Availability;Additional Points;Ethical Approval;Consent;Disclosure;Conflicts of Interest;Authors’ Contributions;Funding Statement;Acknowledgements;Supplementary Materials;References;Appendix;Abbreviations;Preliminaries;Introduction and Preliminaries;Notation;Proof of Theorem;Proofs;Analysis of Results;Examples;Numerical Example;Applications;Numerical Simulation;Model;Model Formulation;Systematic Palaeontology;Nomenclatural Acts;Taxonomic Implications;Experimental;Synthesis;Overview;Characterization;Background;Experimental;Theories;Calculations;Model Verification;Model Implementation;Geographic location;Study Area;Geological setting;Data Collection;Field Testing;Data and Sampling;Dataset;Literature Review;Related Works;Related Work;System Model;Methods and Data;Experimental Results;Results and Analysis;Evaluation;Implementation;Case Presentation;Case Report;Search Terms;Case Description;Case Series;Background;Limitations;Additional Points;Case;Case 1;Case 2 etc.;Concern Details;Retraction Details;Copyright;Related Articles
摘要：
The research group utilized the estimation model of energy consumption capacity for reinforced concrete components without axial force to assess the energy consumption capacity of 92-reinforced concrete components from the PEER database, which were subjected to axial force and bending. The study also examined the impact of design parameters, including longitudinal reinforcement ratio, transverse reinforcement ratio, axial compression ratio, and shear-span ratio, on the estimation results. The research findings revealed that when applying the estimation model of energy consumption capacity for reinforced concrete components without axial force to calculate the energy consumption capacity of reinforced concrete components with axial force, there was a significant deviation rate in the estimation of cumulative energy consumption. The relationship between the deviation rate of cumulative energy consumption and longitudinal reinforcement ratio, axial compression ratio, and shear-span ratio remained unclear. However, a more apparent linear relationship was observed with the transverse reinforcement ratio. By conducting a quantitative analysis of the transverse reinforcement ratio, the researchers proposed an modified estimation model of energy consumption capacity for reinforced concrete components with axial force. Nonetheless, the accuracy of the modified estimation model was found to be high within the range of 0–250,000 kN mm of cumulative energy consumption. For cumulative energy consumption exceeding 250,000 kN mm, further experimental and theoretical research is still required to enhance the reliability of the modified estimation model.
