期刊：
Resources, Conservation and Recycling,2025年215:108096 ISSN：0921-3449
通讯作者：
Liu, B
作者机构：
[Liu, Bin; Pan, Wei; Liu, B; Yu, Cong] Univ Hong Kong, Dept Civil Engn, Hong Kong 999077, Peoples R China.;[Liu, Bin; Liu, B; Li, Jingjing] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Dept Engn Management, Changsha 410114, Peoples R China.;[Kumar, Pankaj] Inst Global Environm Strategies, Hayama 2400115, Japan.;[Chen, Yifan] Zhejiang Univ Water Resources & Elect Power, Coll Water Conservancy & Environm Engn, Hangzhou 310018, Peoples R China.
通讯机构：
[Liu, B ] U;Univ Hong Kong, Dept Civil Engn, Hong Kong 999077, Peoples R China.;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Dept Engn Management, Changsha 410114, Peoples R China.
关键词：
Sustainable development;Water resilience;Nature-society dual water cycle;Climate change;Spatiotemporal analysis;China
摘要：
Water cycle resilience represents a vital part of sustainable water resources management for a region with severe water vulnerability issues. However, despite their importance, a current lack of systematic monitoring mechanisms has contributed to an insufficient grasp of their distribution in relation to water resources management practices, as well as their vulnerability to climate change and human impacts. This study develops a nature-society water cycle resilience index that integrates recover and supplement to water vulnerability, which is applied in the case study of China. The results indicate that the comprehensive level of water cycle resilience in China has been constantly improving in the past two decades, whilst varies significantly among provinces in water resources management performance and serious vulnerability issues. This study provides useful references for countries or large-scale regions around the world to promote resilience and sustainability in water resources planning and policy.
Water cycle resilience represents a vital part of sustainable water resources management for a region with severe water vulnerability issues. However, despite their importance, a current lack of systematic monitoring mechanisms has contributed to an insufficient grasp of their distribution in relation to water resources management practices, as well as their vulnerability to climate change and human impacts. This study develops a nature-society water cycle resilience index that integrates recover and supplement to water vulnerability, which is applied in the case study of China. The results indicate that the comprehensive level of water cycle resilience in China has been constantly improving in the past two decades, whilst varies significantly among provinces in water resources management performance and serious vulnerability issues. This study provides useful references for countries or large-scale regions around the world to promote resilience and sustainability in water resources planning and policy.
摘要：
Currently, isocyanate modified asphalt (IMA) has gradually attracted attention in the pavement field due to its good mechanical properties and environmental benefits. However, there also exists some challenges, such as high viscosity and poor low-temperature performance, for its further application. In this study, an environmental-friendly potential solving method is proposed by employing waste engine oil (WEO) as a co-modifier with polyaryl polymethylene isocyanate (PAPI). And the effect and modification mechanism of WEO and PAPI on neat asphalt are studied. Specifically, the optimal compositions of PAPI/WEO modified asphalt (PWMA) were firstly determined by learning the effects of the PAPI and WEO amounts on the viscosity, high- and low- temperature performance of neat asphalt. Then, the traditional physical properties, storage stability and aging resistance of PWMA and SBS modified asphalt (SBSMA) were analyzed and compared. Finally, the performance improvement mechanism of PWMA was detected by microscopic analyses. The result shows that adopting WEO as a kind of co-modifier can prepare excellent performance modified asphalt with PAPI. The prepared PWMA qualifies similar viscosity and high- and low- temperature performance to SBSMA, while has the better storage stability and aging resistance. Microscopic test results reveal that in the PWMA, PAPI reacts chemically with the neat asphalt to generate carbamate or urea macromolecular products, while WEO mainly plays the role of adsorbent and filler. These findings are significant for guiding the performance regulation of IMA by the environmental-friendly method.
Currently, isocyanate modified asphalt (IMA) has gradually attracted attention in the pavement field due to its good mechanical properties and environmental benefits. However, there also exists some challenges, such as high viscosity and poor low-temperature performance, for its further application. In this study, an environmental-friendly potential solving method is proposed by employing waste engine oil (WEO) as a co-modifier with polyaryl polymethylene isocyanate (PAPI). And the effect and modification mechanism of WEO and PAPI on neat asphalt are studied. Specifically, the optimal compositions of PAPI/WEO modified asphalt (PWMA) were firstly determined by learning the effects of the PAPI and WEO amounts on the viscosity, high- and low- temperature performance of neat asphalt. Then, the traditional physical properties, storage stability and aging resistance of PWMA and SBS modified asphalt (SBSMA) were analyzed and compared. Finally, the performance improvement mechanism of PWMA was detected by microscopic analyses. The result shows that adopting WEO as a kind of co-modifier can prepare excellent performance modified asphalt with PAPI. The prepared PWMA qualifies similar viscosity and high- and low- temperature performance to SBSMA, while has the better storage stability and aging resistance. Microscopic test results reveal that in the PWMA, PAPI reacts chemically with the neat asphalt to generate carbamate or urea macromolecular products, while WEO mainly plays the role of adsorbent and filler. These findings are significant for guiding the performance regulation of IMA by the environmental-friendly method.
作者机构：
[Shanlin Xu; Lingkai Hu; Honglei Sun; Bo Wang] College of Civil Engineering, Zhejiang University of Technology, Hangzhou, China;[Feng Gao] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, China;[Mingyuan Wang] Power China Huadong Engineering Corporation, Hangzhou, China
通讯机构：
[Lingkai Hu] C;College of Civil Engineering, Zhejiang University of Technology, Hangzhou, China
关键词：
Discrete element method;Gap-graded soils;Particle size distribution;Peak strength;Anisotropy;Predictive formula
摘要：
Gap-graded soils, extensively utilized in geotechnical and hydraulic engineering, exhibit diverse strength characteristics governed by their distinctive particle size distribution (PSD). To investigate the influence of PSD on the shear strength of gap-graded soils, this study utilizes the Discrete Element Method (DEM) to reproduce drained conventional triaxial tests of gap-graded soils across a wide range of fine particle content (FC = 1-40%) and particle size ratio (SR = 2.5-6.0). The simulation results reveal that the peak shear strength follows a characteristic unimodal curve versus FC, attaining its maximum value at about FC = 25%. SR governs peak strength through critical FC thresholds: negligible impact at FC < 10%, whereas significant enhancement occurs at FC = 25%. Micromechanical analysis reveals that branch anisotropy evolution controls strength behaviour. Shear strength inversely correlates with peak branch anisotropy as reduced branch anisotropy promotes homogenized contact force distribution. FC and SR collectively regulate macroscopic strength through coupled control of branch anisotropy evolution, where their synergistic interaction governs force chain reorganization and stress distribution homogeneity. Based on these insights, a novel predictive formula for peak strength incorporating both SR and FC were proposed, providing guidance for optimized deployment of gap-graded soils in engineering practice.
作者机构：
[Min Wang] College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China;School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China;College of Water Conservancy & Hydropower Engineering, Hohai University, Nanjing 210098, China;National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China;[Xin Yu] College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China<&wdkj&>School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China
通讯机构：
[Xin Yu] C;College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China<&wdkj&>School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha 410114, China
摘要：
The occurrence of top-down (TD) cracking has gradually become a prevalent issue in semi-rigid base asphalt pavements after prolonged service. A coupled simulation model integrating the finite difference method (FDM) and discrete element method (DEM) was employed to investigate the mechanical behavior of asphalt pavement containing a pre-existing TD crack. The mesoscopic parameters of the model were calibrated based on the mixture modulus and the static mechanical response on the MLS66 test road. Finally, an analysis was performed to assess how variations in TD crack depth and longitudinal length affect the distribution patterns of transverse tensile stress, vertical shear stress, and vertical compressive stress. The results indicate that the vertical propagation of TD crack significantly increases both the tensile stress value and range on the middle surface, while the longitudinal development of TD crack has minimal impact. This phenomenon may result in more severe fatigue failure on the middle surface. With the vertical and longitudinal development of TD crack, the vertical shear stress and compressive stress show obvious "two-stage" characteristics. When the crack's vertical length reaches 40 mm, there is a sharp increase in stress on the upper surface. As the crack continues to propagate vertically, the growth of stress on the upper surface becomes negligible, while the stress in the middle and lower layers increased significantly. Conversely, for longitudinal development of TD crack, any changes in stress are insignificant when their length is less than 180 mm; however, as they continue to develop longitudinally beyond this threshold, there is a sharp increase in stress levels. These findings hold great significance for understanding pavement structure deterioration and maintenance behavior associated with TD crack.
The occurrence of top-down (TD) cracking has gradually become a prevalent issue in semi-rigid base asphalt pavements after prolonged service. A coupled simulation model integrating the finite difference method (FDM) and discrete element method (DEM) was employed to investigate the mechanical behavior of asphalt pavement containing a pre-existing TD crack. The mesoscopic parameters of the model were calibrated based on the mixture modulus and the static mechanical response on the MLS66 test road. Finally, an analysis was performed to assess how variations in TD crack depth and longitudinal length affect the distribution patterns of transverse tensile stress, vertical shear stress, and vertical compressive stress. The results indicate that the vertical propagation of TD crack significantly increases both the tensile stress value and range on the middle surface, while the longitudinal development of TD crack has minimal impact. This phenomenon may result in more severe fatigue failure on the middle surface. With the vertical and longitudinal development of TD crack, the vertical shear stress and compressive stress show obvious "two-stage" characteristics. When the crack's vertical length reaches 40 mm, there is a sharp increase in stress on the upper surface. As the crack continues to propagate vertically, the growth of stress on the upper surface becomes negligible, while the stress in the middle and lower layers increased significantly. Conversely, for longitudinal development of TD crack, any changes in stress are insignificant when their length is less than 180 mm; however, as they continue to develop longitudinally beyond this threshold, there is a sharp increase in stress levels. These findings hold great significance for understanding pavement structure deterioration and maintenance behavior associated with TD crack.
期刊：
Bulletin of Engineering Geology and the Environment,2025年84(4):1-16 ISSN：1435-9529
通讯作者：
Junhui Zhang<&wdkj&>Jin Chang
作者机构：
School of smart construction and energy engineering, Hunan Institute of Engineering, Xiangtan, China;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, China;Hunan Provincial Engineering Research Center for Disaster and Reinforcement of Disease Risk Engineering Structures, Xiangtan, China;Key Laboratory of Highway Engineering of Ministry of Education, Changsha University of Science & Technology, Changsha, China;[Jin Chang] Hunan Provincial Key Laboratory for Big Data Smart Application of Natural Disaster Risks, Survey of Highway Engineering, Changsha University, Changsha, China
通讯机构：
[Junhui Zhang] K;[Jin Chang] H;Key Laboratory of Highway Engineering of Ministry of Education, Changsha University of Science & Technology, Changsha, China<&wdkj&>School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, China<&wdkj&>Hunan Provincial Key Laboratory for Big Data Smart Application of Natural Disaster Risks, Survey of Highway Engineering, Changsha University, Changsha, China
摘要：
This paper presents a theoretical analysis of the damage evolution law of carbonaceous mudstone during compressive failure process under dry–wet cycling. In this study, microscopic testing and uniaxial compression synchronous acoustic emission testing systems are employed to examine the microstructure, mechanical properties, and failure acoustic signal of carbonaceous mudstone. The results demonstrated that dry–wet cycling aggravated the mesostructure damage of carbonaceous mudstone. As the dry–wet cycling increased, the pores of carbonaceous mudstone increased, and the disorganization of the mesostructure became more serious, leading to reductions in peak stress, elastic modulus, and cumulative acoustic emission signals. The analysis of PFC (Partical Flow Code) revealed that the number of crack propagation in carbonaceous mudstone increased, and the crack morphology became more complex under dry–wet cycling. A comprehensive framework was developed to incorporate crack propagation into the damage process, where in the growth of cracks exhibits an "S-shaped" pattern with axial strain. As the number of dry–wet cycling increased, the threshold strain for the accelerated damage increased, and the crack growth rate decreased, along with a decrease in the initiation damage stress. This damage pattern was further evidenced by the identification of the crack propagation morphology and rock failure localization during dry–wet cycling. The proposed method showed good consistency with the experimental test results and numerical simulations, enabling quantitative calculation of compression-induced damage in carbonaceous mudstone.
摘要：
Hot mix asphalt mixture is considered the ideal approach to reuse waste plastics in high-value applications because of its very high amount of usage in highway construction. However, the differences in polarity and density between polymers and asphalt lead to polymer coalescence and therefore the poor storage stability of modified asphalt. These challenges are exalted when recycling commingled plastics. This study introduced an innovative compatibilization strategy and mechanism for co-stabilizing commingled plastics and pyrolyzed rubber in asphalt. Commingled plastics were first grafted with maleic anhydride for surface activation, followed by reactive kneading with pyrolyzed rubber and crosslinking agent to form an integrated thermoplastic elastomer (ITPE) for asphalt modification. The mechanical, thermal, and interfacial behaviors of the ITPE were evaluated through tensile testing, thermogravimetric analysis, and scanning electron microscopy. The storage stability and rheological properties of the modified binder blends were evaluated through the cigar tube test and dynamic shear rheometer testing. Results demonstrated a successful formation of imide bonds in the ITPE, which can improve the strength, ductility, and thermal stability of rubber-plastic composites. Appropriate utilization of crosslinking agents can improve both rutting and fatigue resistance of ITPE-modified asphalt with good storage stability because of the co-existence of rigid plastic and soft rubbery regimes and the formation of a crosslink network. However, excessive content of crosslinker led to severe phase separation and reduced storage stability of modified binder blends. Extra crosslinker tended to float in asphalt because of its low density and caused an excessive formation of the crosslink network in the top section of the asphalt.
期刊：
Soil Dynamics and Earthquake Engineering,2025年194:109362 ISSN：0267-7261
通讯作者：
Zipeng Ma
作者机构：
[Sixun Wen; Haibin Wei; Zipeng Ma] College of Transportation, Jilin University, No. 5988, Renmin Street, City of Changchun, Jilin, 130022, China;Guangxi Key Lab of Road Structure and Materials, Nanning, 530007, China;Guangxi Transportation Science and Technology Group Co., Ltd., Nanning, 530007, China;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, 410114, China;[Yangpeng Zhang] Guangxi Key Lab of Road Structure and Materials, Nanning, 530007, China<&wdkj&>Guangxi Transportation Science and Technology Group Co., Ltd., Nanning, 530007, China<&wdkj&>School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha, 410114, China
通讯机构：
[Zipeng Ma] C;College of Transportation, Jilin University, No. 5988, Renmin Street, City of Changchun, Jilin, 130022, China
摘要：
As an emerging environmentally friendly solid waste-based composite foam lightweight soil, saponified slag fly ash (SS-FA) foam lightweight soil has a wide range of application prospects in road engineering. In this paper, the dynamic characteristics of SS-FA foam light soil material were investigated. Dynamic triaxial tests under different cyclic loading conditions were designed to analyze the variation rules of dynamic elastic modulus and damping ratio. The results showed that the stress-strain curve of SS-FA foam lightweight soil can be divided into three stages: elastic stage, plateau stage, and stress yielding stage. Under cyclic dynamic load, with the increase of dynamic stress amplitude, the dynamic elastic modulus of 400–700 kg/m3 samples gradually increased to the maximum, reaching 235.24 MPa, 324.54 MPa, 356.45 MPa, 379.67 MPa, respectively. The damping ratio, on the other hand, shows a tendency to first decrease and then slowly increase to stabilize. The dynamic elastic modulus is positively correlated with density grade, confining pressure and loading frequency. The damping ratio decreases with the increase of density grade and loading frequency, and increases with the increase of confining pressure. The electron microscope test was designed and image processing and data statistics were carried out. Through the grey correlation analysis, the correlation degree between the microstructure parameters of SS-FA foamed lightweight soil and the macroscopic mechanical properties is basically above 0.6, indicating that the two have a significant correlation. A normalized prediction formula model between the dynamic elastic modulus of materials and the conditional parameters was established. The R 2 of the linear fitting of the predicted value is 0.964, indicating that the prediction model has a high degree of fitting and a good prediction effect. The research results revealed the dynamic mechanical properties of foamed lightweight soil, and provided a reference for the application of SS-FA foamed lightweight soil in subgrade engineering.
As an emerging environmentally friendly solid waste-based composite foam lightweight soil, saponified slag fly ash (SS-FA) foam lightweight soil has a wide range of application prospects in road engineering. In this paper, the dynamic characteristics of SS-FA foam light soil material were investigated. Dynamic triaxial tests under different cyclic loading conditions were designed to analyze the variation rules of dynamic elastic modulus and damping ratio. The results showed that the stress-strain curve of SS-FA foam lightweight soil can be divided into three stages: elastic stage, plateau stage, and stress yielding stage. Under cyclic dynamic load, with the increase of dynamic stress amplitude, the dynamic elastic modulus of 400–700 kg/m3 samples gradually increased to the maximum, reaching 235.24 MPa, 324.54 MPa, 356.45 MPa, 379.67 MPa, respectively. The damping ratio, on the other hand, shows a tendency to first decrease and then slowly increase to stabilize. The dynamic elastic modulus is positively correlated with density grade, confining pressure and loading frequency. The damping ratio decreases with the increase of density grade and loading frequency, and increases with the increase of confining pressure. The electron microscope test was designed and image processing and data statistics were carried out. Through the grey correlation analysis, the correlation degree between the microstructure parameters of SS-FA foamed lightweight soil and the macroscopic mechanical properties is basically above 0.6, indicating that the two have a significant correlation. A normalized prediction formula model between the dynamic elastic modulus of materials and the conditional parameters was established. The R 2 of the linear fitting of the predicted value is 0.964, indicating that the prediction model has a high degree of fitting and a good prediction effect. The research results revealed the dynamic mechanical properties of foamed lightweight soil, and provided a reference for the application of SS-FA foamed lightweight soil in subgrade engineering.
期刊：
Construction and Building Materials,2025年471:140709 ISSN：0950-0618
通讯作者：
Huanan Yu
作者机构：
[Chao Zhang; Taojun Li; Yalong Zhang; Wan Dai; Jinguo Ge] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China;National Engineering Research Center of Highway Maintenance Technology, Changsha 410114, China;[Menglei Lou] Guangxi Xinfazhan Communication Group CO., Ltd, Nanning 530029, China;[Huanan Yu; Guoping Qian; Xiangbing Gong] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha 410114, China
通讯机构：
[Huanan Yu] S;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>National Engineering Research Center of Highway Maintenance Technology, Changsha 410114, China
摘要：
The influence mechanism of steel slag as coarse aggregate on the performance of asphalt mixture is not clear. This study starts from the influence of steel slag replacing limestone on the interaction between asphalt and aggregate interface. The interlayer device of the DSR test was improved, and steel slag-asphalt-steel slag (SAS), limestone-asphalt-steel slag (LAS), and limestone-asphalt-limestone (LAL) interlayers were constructed, in which LAS and SAS characterize the partial or total replacement of steel slag for limestone, respectively. The rheological behavior and uniaxial tensile failure characteristics of different interlayer systems were studied. The effect of steel slag replacing limestone on the interfacial interaction was characterized by the evolution of interfacial asphalt performance. The results showed that the influence of temperature and frequency on the complex shear modulus G* was greater than that of lithology and film thickness. Steel slag instead of limestone could increase the G* of interfacial asphalt. The fatigue resistance of interface asphalt gradually increased with the increase of temperature, and the fatigue performance of LAS and SAS interlayer interface asphalt formed by steel slag instead of limestone showed differences. Replacing limestone with steel slag could improve the long-term relaxation ability of interfacial asphalt. The substitution of steel slag for limestone had no negative effect on the tensile properties of interfacial asphalt, and the effect of temperature and film thickness on strength was more obvious than that of loading rate. The research results provided scientific guidance for promoting the resource utilization of steel slag.
The influence mechanism of steel slag as coarse aggregate on the performance of asphalt mixture is not clear. This study starts from the influence of steel slag replacing limestone on the interaction between asphalt and aggregate interface. The interlayer device of the DSR test was improved, and steel slag-asphalt-steel slag (SAS), limestone-asphalt-steel slag (LAS), and limestone-asphalt-limestone (LAL) interlayers were constructed, in which LAS and SAS characterize the partial or total replacement of steel slag for limestone, respectively. The rheological behavior and uniaxial tensile failure characteristics of different interlayer systems were studied. The effect of steel slag replacing limestone on the interfacial interaction was characterized by the evolution of interfacial asphalt performance. The results showed that the influence of temperature and frequency on the complex shear modulus G* was greater than that of lithology and film thickness. Steel slag instead of limestone could increase the G* of interfacial asphalt. The fatigue resistance of interface asphalt gradually increased with the increase of temperature, and the fatigue performance of LAS and SAS interlayer interface asphalt formed by steel slag instead of limestone showed differences. Replacing limestone with steel slag could improve the long-term relaxation ability of interfacial asphalt. The substitution of steel slag for limestone had no negative effect on the tensile properties of interfacial asphalt, and the effect of temperature and film thickness on strength was more obvious than that of loading rate. The research results provided scientific guidance for promoting the resource utilization of steel slag.
摘要：
The mesostructure of the asphalt mixture, being intricate and varied, poses a significant challenge in accurately analyzing its distribution throughout various stages of compaction. CT scanning was employed to obtain digital images of PAC-13 asphalt mixture, convolutional neural networks were utilized for multi-component segmentation and three-dimensional reconstruction, with the aim of studying the evolution of the mesostructure of PAC-13 during the compaction process and correlating it with its macro-performance. The results showed that as the continuous compaction, the vertically distribution of voids in the middle of PAC-13 tended to become more uniform, the principal axes of most aggregates were stably aligned at a 90° angle to the Y-axis, and the migration of aggregates was tend to more tightly ordered and compact. Moreover, the principal axis inclination exhibited significant correlations with flow frequency and splitting strength, with R2 values of 0.94 and 0.92 respectively, establishing it as an effective mesostructure index for reflecting macroscopic mechanical properties. This study provided an effective basis for the construction optimization of asphalt paving material.
The mesostructure of the asphalt mixture, being intricate and varied, poses a significant challenge in accurately analyzing its distribution throughout various stages of compaction. CT scanning was employed to obtain digital images of PAC-13 asphalt mixture, convolutional neural networks were utilized for multi-component segmentation and three-dimensional reconstruction, with the aim of studying the evolution of the mesostructure of PAC-13 during the compaction process and correlating it with its macro-performance. The results showed that as the continuous compaction, the vertically distribution of voids in the middle of PAC-13 tended to become more uniform, the principal axes of most aggregates were stably aligned at a 90° angle to the Y-axis, and the migration of aggregates was tend to more tightly ordered and compact. Moreover, the principal axis inclination exhibited significant correlations with flow frequency and splitting strength, with R2 values of 0.94 and 0.92 respectively, establishing it as an effective mesostructure index for reflecting macroscopic mechanical properties. This study provided an effective basis for the construction optimization of asphalt paving material.
摘要：
Background : A ramp is an auxiliary roadway that facilitates the vehicles joining and leaving the main traffic stream of highway. Ramp areas are prone to road crashes because of the merging, diverging, and weaving traffic entering and leaving the highways. Objectives : This study evaluates the differences in injury severity and influencing factors between single- and multi-vehicle crashes at ramp areas, with which the transferability assessment of models across time periods is considered. Method: Separate injury severity models for single- and multi-vehicle crashes are established based on comprehensive crash data from North Carolina State in 2016–2018. Random parameter multinomial logit regression model with heterogeneity in means and variances is adopted to measure the association between crash injury severity and possible influencing factors, with which the effect of unobserved heterogeneity is accounted. In addition, partially constrained and temporal unconstrained modeling approaches are adopted to consider temporally shifting parameters. Results: Results indicate that there are considerable differences in the effects on injury severity between single- and multi-vehicle crashes, after controlling for unobserved heterogeneity and temporal instability. Some variables including aberrant driving, vehicle type, area type, speed limit and crash location are found to be significant only in one type of crash but not in the other. There are opposite effects for the crashes in rural areas on the likelihood of injury between single-vehicle and multi-vehicle crashes. Additionally, temporal transferability and out-of-sample prediction performance for models of single- and multi-vehicle crashes are assessed. Results indicate that remarkable temporal stability and instability coexist. Practical Applications : Findings should shed light on the effective traffic management and control strategies that can mitigate crash and injury risk at highway ramp areas.
Background : A ramp is an auxiliary roadway that facilitates the vehicles joining and leaving the main traffic stream of highway. Ramp areas are prone to road crashes because of the merging, diverging, and weaving traffic entering and leaving the highways. Objectives : This study evaluates the differences in injury severity and influencing factors between single- and multi-vehicle crashes at ramp areas, with which the transferability assessment of models across time periods is considered. Method: Separate injury severity models for single- and multi-vehicle crashes are established based on comprehensive crash data from North Carolina State in 2016–2018. Random parameter multinomial logit regression model with heterogeneity in means and variances is adopted to measure the association between crash injury severity and possible influencing factors, with which the effect of unobserved heterogeneity is accounted. In addition, partially constrained and temporal unconstrained modeling approaches are adopted to consider temporally shifting parameters. Results: Results indicate that there are considerable differences in the effects on injury severity between single- and multi-vehicle crashes, after controlling for unobserved heterogeneity and temporal instability. Some variables including aberrant driving, vehicle type, area type, speed limit and crash location are found to be significant only in one type of crash but not in the other. There are opposite effects for the crashes in rural areas on the likelihood of injury between single-vehicle and multi-vehicle crashes. Additionally, temporal transferability and out-of-sample prediction performance for models of single- and multi-vehicle crashes are assessed. Results indicate that remarkable temporal stability and instability coexist. Practical Applications : Findings should shed light on the effective traffic management and control strategies that can mitigate crash and injury risk at highway ramp areas.
摘要：
Objective This study aims to address the limitations of using historical crash data and trajectory data for crash and conflict identification. Specifically, it focuses on enhancing real-time conflict identification by investigating the influence of traffic flow state variables and their interactions on conflicts.
This study aims to address the limitations of using historical crash data and trajectory data for crash and conflict identification. Specifically, it focuses on enhancing real-time conflict identification by investigating the influence of traffic flow state variables and their interactions on conflicts.
Methods Vehicle trajectory data from HighD were processed, allowing extraction of traffic flow state and corresponding conflict during a specific time interval (10 s). Logistic regression models were further used to verify the impact of variables, including interaction terms, on the conflicts for different lane categories (inner, middle, and outer lanes). Additionally, machine learning techniques were employed to compare conflict identification performance including or excluding variable interactions.
Vehicle trajectory data from HighD were processed, allowing extraction of traffic flow state and corresponding conflict during a specific time interval (10 s). Logistic regression models were further used to verify the impact of variables, including interaction terms, on the conflicts for different lane categories (inner, middle, and outer lanes). Additionally, machine learning techniques were employed to compare conflict identification performance including or excluding variable interactions.
Results The interaction terms of the traffic flow state variables have significant effects on the conflicts for different categories of lanes. It is therefore essential to consider both the individual effects of traffic variables and their interaction effects to analyze conflict risk. Considering variable interactions leads to improved conflict identification accuracy and reduced identification error rates in comparison to the condition where interaction items are not taken into account.
The interaction terms of the traffic flow state variables have significant effects on the conflicts for different categories of lanes. It is therefore essential to consider both the individual effects of traffic variables and their interaction effects to analyze conflict risk. Considering variable interactions leads to improved conflict identification accuracy and reduced identification error rates in comparison to the condition where interaction items are not taken into account.
Conclusions The interaction terms of traffic flow state variables significantly affect and enhance conflict identification, improving accuracy and reducing error rates. These findings contribute to advancing the high-precision identification of real-time conflict identification, with implications for improving road safety measures.
The interaction terms of traffic flow state variables significantly affect and enhance conflict identification, improving accuracy and reducing error rates. These findings contribute to advancing the high-precision identification of real-time conflict identification, with implications for improving road safety measures.
摘要：
LED lamps could save energy and improve road safety by replacing traditional street lamps. Still, the reflective properties of asphalt pavement under LED light sources have yet to be studied enough. The correlation between texture indicators and optical parameters measured at different locations of asphalt mixture specimens under LED light source was investigated to study the influence mechanism of asphalt pavement type and texture characteristics on light reflection characteristics. According to normalization, the equivalent of reflection coefficients and luminance correlate with the Mean Texture Depth ( MTD ) and the Root Mean Square Slope ( Δq ). A quantitative expression model of the reflection properties was developed. The results showed that the texture characteristics influenced the luminance and reflection coefficients of different asphalt mixtures. The maximum nominal particle size was larger, the luminance was lower, and the reflection coefficient was smaller. Various types of asphalt pavements absorb light to varying degrees due to differences in void ratio and surface structure. The reflection coefficients and luminance of the asphalt mixture specimens showed a good fit with both the single-factor and multifactor expression models developed for MTD and Δq . The test results showed that the multifactor linear model had the highest overall prediction accuracy. The model revealed the mechanism by which texture indicators influence the illumination efficiency of pavement surfaces. The research results have provided a reference basis for optimizing the layout of roadway lighting equipment and a scientific basis for improving the safety of roadway lighting.
LED lamps could save energy and improve road safety by replacing traditional street lamps. Still, the reflective properties of asphalt pavement under LED light sources have yet to be studied enough. The correlation between texture indicators and optical parameters measured at different locations of asphalt mixture specimens under LED light source was investigated to study the influence mechanism of asphalt pavement type and texture characteristics on light reflection characteristics. According to normalization, the equivalent of reflection coefficients and luminance correlate with the Mean Texture Depth ( MTD ) and the Root Mean Square Slope ( Δq ). A quantitative expression model of the reflection properties was developed. The results showed that the texture characteristics influenced the luminance and reflection coefficients of different asphalt mixtures. The maximum nominal particle size was larger, the luminance was lower, and the reflection coefficient was smaller. Various types of asphalt pavements absorb light to varying degrees due to differences in void ratio and surface structure. The reflection coefficients and luminance of the asphalt mixture specimens showed a good fit with both the single-factor and multifactor expression models developed for MTD and Δq . The test results showed that the multifactor linear model had the highest overall prediction accuracy. The model revealed the mechanism by which texture indicators influence the illumination efficiency of pavement surfaces. The research results have provided a reference basis for optimizing the layout of roadway lighting equipment and a scientific basis for improving the safety of roadway lighting.
关键词：
sustainable transportation;freeway crash;injury severity;interactive effect;random parameters logit model
摘要：
Freeway transportation safety issues have attracted public concern in China for decades. This study aims to identify the factors influencing the injury severity of freeway crashes and to quantify their effects on the likelihood of various crash severity levels, with consideration of heterogeneity and interactions. The empirical analysis is based on three years of crash data from two mountainous freeways in Guangdong, China, covering the years of 2021 to 2023. A random parameters logit model with interaction terms is developed for the analysis. Goodness-of-fit indicators reveal that accommodating the interactive effects can significantly improve model fit performance. The estimation results of the parameters and marginal effects indicate that the factors related to vehicle type, time of day, crash season and cause, 3D curvature, and traffic volume have significant effects on crash severity. Notably, interactive effects are revealed between spring and evening, autumn and fixed objects, and non-local vehicles and improper driving. According to the findings, some countermeasures on safety education, traffic management, and freeway design are provided for preventing freeway crash injury, which is helpful for the development of sustainable transportation systems.
作者机构：
[Li, Tao; Li, Jixiao] Key Laboratory of Safety Control of Bridge Engineering, Ministry of Education, Changsha University of Science & Technology, Changsha 410114, China;[Li, Tao; Li, Jixiao] School of Civil and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China;[Li, Tao; Li, Jixiao] National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment, Changsha 410114, China;[Li, Bingyang] Elite Engineering School, Changsha University of Science & Technology, Changsha 410114, China;[Yu, Guangtao] School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China
摘要：
In order to investigate the influence of the coexistence of clay and silt on the compression characteristics of sand, one-dimensional compression consolidation tests were carried out on reconstituted saturated sand-silt-clay mixtures with a constant initial void ratio, and the effects of fines content (FC) and clay-silt ratio (CS) on the compression characteristics of mixed soils were studied. The mechanism of the experimental results was additionally explained from a microscopic perspective. The test results show that: the compressibility of mixed soil increased with the increase in FC; the compressibility change rule of mixed soils with different CS is consistent under the same FC; the influence of CS on the e-lgp (the void ratio (e) versus logarithm of the pressure (p)) curve of mixed soil is inconsistent when FC is different: when FC = 3%, the compressibility of mixed soil decreased with the increase in CS; when FC = 7% and 10%, the compressibility of mixed soil gradually increased with the increase in CS; when FC = 5%, the compressibility of mixed soil did not show an obvious changing law with the increase in CS, and the compressibility of the specimen with FC = 5%-CS = 1 (FC = 5%, CS = 1) was the largest; when CS was same, the difference between e-lgp curves of mixed soil with different FC increased with the increase in CS. The compression model of sand-silt-clay mixtures was established, which can consider the effects of FC and CS. The reliability and applicability of the proposed model were verified by combining the experimental results of this paper and the test data of sand-clay mixture and sand-silt mixture in other literature.
摘要：
This research analyzed the characteristics of aggregate contact chain networks based on complex network theory. The contact chain network was extracted using Digital Image Processing (DIP) technology and Three-Dimensional (3D) reconstruction technology. The change rule of the contact chain network of asphalt mixture was analyzed using the complex network theory. From the results of the analysis, the filling particles existed during the compaction. The 4.75–9.5 mm and 9.5–13.2 mm aggregates may rotate to increase the stability of the skeleton structure. The clustering coefficient of the aggregate increased as the asphalt mixture was compacted, and the aggregate with a small size had a larger clustering coefficient. The distribution of shortest path length in each compaction stage obeyed the Gaussian distribution. The average shortest path length decreased with the increase of the compactness of the specimen, indicating that there was a good correlation between shortest path length and compactness.
This research analyzed the characteristics of aggregate contact chain networks based on complex network theory. The contact chain network was extracted using Digital Image Processing (DIP) technology and Three-Dimensional (3D) reconstruction technology. The change rule of the contact chain network of asphalt mixture was analyzed using the complex network theory. From the results of the analysis, the filling particles existed during the compaction. The 4.75–9.5 mm and 9.5–13.2 mm aggregates may rotate to increase the stability of the skeleton structure. The clustering coefficient of the aggregate increased as the asphalt mixture was compacted, and the aggregate with a small size had a larger clustering coefficient. The distribution of shortest path length in each compaction stage obeyed the Gaussian distribution. The average shortest path length decreased with the increase of the compactness of the specimen, indicating that there was a good correlation between shortest path length and compactness.
作者机构：
[Liwan Shi; XiongXin Li; Hehao Liang] School of Transportation and Civil Engineering and Architecture, Foshan University, Foshan, Guangdong, China;[Hongjie Guo] Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China;Foshan Road and Bridge Supervision Station Co., Ltd., Foshan, Guangdong 528041, China;Foshan Transportation Science and Technology Co., Ltd., Foshan, Guangdong 528041, China;[Rong Zhou] Guangzhou Jishan Construction Technology Co., Ltd, Guangzhou, Guangdong, China
通讯机构：
[Hehao Liang] S;School of Transportation and Civil Engineering and Architecture, Foshan University, Foshan, Guangdong, China
期刊：
Solar Energy Materials and Solar Cells,2025年286:113531 ISSN：0927-0248
通讯作者：
Huan Zhang
作者机构：
[Jiandi Ren; Sheng Xiao; Huan Zhang; Jianlin Chen] School of Energy and Power Engineering, Changsha University of Science and Technology, 410114, Changsha, China;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, 410114, Changsha, China;[Yanjie Ren] School of Mechanical and Energy Engineering, Zhejiang University of Science and Technology, 310023, Hangzhou, China;CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, 510640, Guangzhou, China;[Changhui Liu] School of Low-Carbon Energy and Power Engineering, China University of Mining and Technology, 221116, Xuzhou, China
通讯机构：
[Huan Zhang] S;School of Energy and Power Engineering, Changsha University of Science and Technology, 410114, Changsha, China
摘要：
The molten salt thermal energy storage system is the most important composition of concentrating solar power plants, resulting in the corrosion behavior of alloys in molten salts is essential to be analyzed to ensure the long-term stability of the system. In this study, the corrosion behavior of TP347H stainless steel, Haynes230 and Inconel625 alloys was investigated in a self-developed novel molten chloride salt (24.5 wt% NaCl-8.2 wt% KCl-67.3 wt% CaCl 2 ). The corrosion mechanism of the alloy samples in molten chloride salts was analyzed through the microscopic characterization and elemental analysis tests. The evolution of alloy sample mass loss versus corrosion time and the main influential factors of the corrosion were analyzed. Corrosion pits appear on the surface of the alloy samples with the increasing corrosion time. Distinct corrosion cracks is observed that on the surface of the Inconel625 sample. Under the condition of 600 °C, the average corrosion rate of TP347H stainless steels is2383.628 μm·a −1 , and those of Haynes230 and Inconel625 are 487.639 μm·a −1 and 5437.520 μm·a −1 . The protective oxide layer within TP347H stainless steels corrosion layer effectively inhibited further matrix corrosion. The superior corrosion resistance of Haynes230 can be attributed to its higher Ni and W content. These results are significant for optimizing the usage of novel molten salts and alloys to achieve long-term stability of the concentrating solar power plants.
The molten salt thermal energy storage system is the most important composition of concentrating solar power plants, resulting in the corrosion behavior of alloys in molten salts is essential to be analyzed to ensure the long-term stability of the system. In this study, the corrosion behavior of TP347H stainless steel, Haynes230 and Inconel625 alloys was investigated in a self-developed novel molten chloride salt (24.5 wt% NaCl-8.2 wt% KCl-67.3 wt% CaCl 2 ). The corrosion mechanism of the alloy samples in molten chloride salts was analyzed through the microscopic characterization and elemental analysis tests. The evolution of alloy sample mass loss versus corrosion time and the main influential factors of the corrosion were analyzed. Corrosion pits appear on the surface of the alloy samples with the increasing corrosion time. Distinct corrosion cracks is observed that on the surface of the Inconel625 sample. Under the condition of 600 °C, the average corrosion rate of TP347H stainless steels is2383.628 μm·a −1 , and those of Haynes230 and Inconel625 are 487.639 μm·a −1 and 5437.520 μm·a −1 . The protective oxide layer within TP347H stainless steels corrosion layer effectively inhibited further matrix corrosion. The superior corrosion resistance of Haynes230 can be attributed to its higher Ni and W content. These results are significant for optimizing the usage of novel molten salts and alloys to achieve long-term stability of the concentrating solar power plants.
摘要：
Double-layer porous asphalt (DLPA) pavement has been gradually applied in China for its efficient water drainage and noise reduction. However, it also faced the challenge of relatively low overall performance for the large air voids. This paper proposed a method of optimizing DLPA structure into a thinner three-layer porous asphalt (TLPA) structure for achieving lower air voids. Specifically, the optimal thickness of porous asphalt (PA) was determined by analyzing the relationship between PA mixture thickness and the degree of segregation. Then the application rate of tack coat between the middle and bottom layers of the TLPA structure was determined. Thirdly, based on the principle of equal drainage speed in TLPA structure, air voids of each PA layer were confirmed by a prediction model, which considered the relationship of air voids, thickness, nominal maximum aggregate size (NMAS), and drainage capacity. Finally, the feasibility of this thin-layer method was validated. Results indicated that PA mixture thickness exhibited good uniformity at 2.5 times of NMAS. It should have considered the effects of air voids, thickness, and NMAS on PA mixture permeability during functional design processes. Converting a DLPA structure to a TLPA structure was feasible, and it could greatly have reduced air voids of the top layer.
Double-layer porous asphalt (DLPA) pavement has been gradually applied in China for its efficient water drainage and noise reduction. However, it also faced the challenge of relatively low overall performance for the large air voids. This paper proposed a method of optimizing DLPA structure into a thinner three-layer porous asphalt (TLPA) structure for achieving lower air voids. Specifically, the optimal thickness of porous asphalt (PA) was determined by analyzing the relationship between PA mixture thickness and the degree of segregation. Then the application rate of tack coat between the middle and bottom layers of the TLPA structure was determined. Thirdly, based on the principle of equal drainage speed in TLPA structure, air voids of each PA layer were confirmed by a prediction model, which considered the relationship of air voids, thickness, nominal maximum aggregate size (NMAS), and drainage capacity. Finally, the feasibility of this thin-layer method was validated. Results indicated that PA mixture thickness exhibited good uniformity at 2.5 times of NMAS. It should have considered the effects of air voids, thickness, and NMAS on PA mixture permeability during functional design processes. Converting a DLPA structure to a TLPA structure was feasible, and it could greatly have reduced air voids of the top layer.
期刊：
Journal of Materials in Civil Engineering,2025年37(5):04025078 ISSN：0899-1561
通讯作者：
Lubiao Liu
作者机构：
[Qiandong Liu; Xikun Ding; Lubiao Liu; Minggu Li; Huihui Li; Lingfeng Wu; Yujie Jiang] Graduate Student, School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China;Graduate Student, Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China;[Chuangmin Li] Professor, School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China;Professor, Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China;[Chuangmin Li] Professor, Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China
通讯机构：
[Lubiao Liu] G;Graduate Student, School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China;Graduate Student, Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China
关键词：
Road engineering;Large-size macadam;Slag powder;Fly ash;Minimum mineral aggregate (VMA);Crack resistance
摘要：
Several studies have highlighted that substituting cement with industrial solid waste materials, such as fly ash and slag powder, can enhance the crack resistance of cement-stabilized macadam bases. A mixture incorporating large particle size gravel exhibits an effective skeleton and support mechanism. To address the issue of cracking in conventional cement-stabilized macadam bases, this paper proposes a novel material: large-size macadam mixture stabilized with industrial solid waste fly ash and slag powder (LSM-SWFS mixture). This study proposes a ratio design method aimed at achieving a tightly packed particle arrangement that facilitates an interlocking, dense structure. By replacing cement with fly ash and slag powder as the cementitious components, the LSM-SWFS mixture was prepared using the vibration compaction method. A series of tests, including unconfined compressive strength, compression modulus of resilience, and flexural-tensile strength assessments showed that the unconfined compressive strength and compression modulus of resilience of the LSM-SWFS mixture were slightly lower than those of the conventional cement-stabilized macadam material. However, its 90 days flexural-tensile strength exhibited a significant increase of 24.9%. Additionally, the drying shrinkage rate of the solid waste mortar specimen over 28 days was only 48.6% of that observed in the cement mortar specimen. The enhancement in flexural-tensile strength alongside the reduction in the drying shrinkage rate underscores the efficiency of the LSM-SWFS mixture in mitigating cracking issues.
摘要：
The underestimated risk of contact erosion failure in railway substructures poses a significant threat to railway safety, particularly at the interface between the ballast/subballast and subgrade. The larger constriction size at this interface exacerbates the potential for long-term erosion, necessitating attention to safeguard railway integrity. This study introduces a novel laboratory erosion testing apparatus to evaluate contact erosion at the subballast-subgrade interface under cyclic loading. Subgrade soils with varying fines contents are tested, and the effect of pressure head on erosion is investigated in detail. The results indicate that sandy soil with higher internal stability exhibits a higher critical pressure head for contact erosion. Cyclic loading induces oscillations in pore water pressure within the subballast layer, with higher pressure heads leading to larger amplitudes. Excess pore water pressure is generated in the sandy soil layer during cyclic loading and gradually dissipates over time. Fine eroded particles migrate into the subballast layer, forming mud, while coarse eroded particles accumulate at the base, creating low-permeability interlayers. Notably, the geometric conditions alone may not guarantee effective prevention of contact erosion in railway substructures. The hydraulic conditions for contact erosion are more easily achieved under cyclic loading compared to static loading. These distinctive features of contact erosion in railway substructures, different from those observed in hydraulic structures, provide some insights for the development of remediation strategies and improvements in railway substructure design.
The underestimated risk of contact erosion failure in railway substructures poses a significant threat to railway safety, particularly at the interface between the ballast/subballast and subgrade. The larger constriction size at this interface exacerbates the potential for long-term erosion, necessitating attention to safeguard railway integrity. This study introduces a novel laboratory erosion testing apparatus to evaluate contact erosion at the subballast-subgrade interface under cyclic loading. Subgrade soils with varying fines contents are tested, and the effect of pressure head on erosion is investigated in detail. The results indicate that sandy soil with higher internal stability exhibits a higher critical pressure head for contact erosion. Cyclic loading induces oscillations in pore water pressure within the subballast layer, with higher pressure heads leading to larger amplitudes. Excess pore water pressure is generated in the sandy soil layer during cyclic loading and gradually dissipates over time. Fine eroded particles migrate into the subballast layer, forming mud, while coarse eroded particles accumulate at the base, creating low-permeability interlayers. Notably, the geometric conditions alone may not guarantee effective prevention of contact erosion in railway substructures. The hydraulic conditions for contact erosion are more easily achieved under cyclic loading compared to static loading. These distinctive features of contact erosion in railway substructures, different from those observed in hydraulic structures, provide some insights for the development of remediation strategies and improvements in railway substructure design.
