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Study On Chloride Ion Diffusion Behavior In Cracked Cement Mortar With High Fly Ash Content, Liu Yang, Mao Shengzhe, Lu Naiwei

Journal of China & Foreign Highway

In order to explore the diffusion behavior of chloride ions in cracked cement mortar with high fly ash (FA) content,this study fabricated cement mortar specimens with different FA contents and crack widths by artificially prefabricating cracks.The chloride ion content in cracks was measured after natural soaking for 30 days and 60 days.The results show that the cracks accelerate the diffusion of chloride ions in cement mortar.The increase in the diffusion coefficient caused by 0.05 mm and 0.1 mm cracks is similar,while that caused by a 0.2 mm crack is significantly higher.After 30 days of soaking,the chloride ion content of the …

Relationship Between Fractal Characteristics And Shear Strength Of Highway Spoil Site Materials, Luo Shixin, Luo Hongming, Zou Fei, Cai Lei

Journal of China & Foreign Highway

Highway spoil features a wide range of particle sizes and poor gradation,and their strength characteristics serve as key factors affecting the stability of spoil slopes.To explore the relationship between fractal characteristics of particle size and strength,this study examined 21 spoil sites along the Guizhou section of the Duyun ‒ Shangri-La Expressway.Based on the field investigation,particle size analysis tests,and laboratory shear tests,the particle composition and shear strength parameters of spoil were obtained.Based on fractal theory,the fractal characteristics of particle size under different gradation scaling methods were analyzed,and the relationship between shear strength parameters and the fractal dimensions of particle size was …

Research On Improvement Of Adhesive Properties Of Asphalt And Granite Gravel, Li Yu, Zhang Yingxue, Qiu Chao, Wang Mo, Liu Li

Journal of China & Foreign Highway

In view of the poor adhesion of acidic granite gravel and asphalt and the shortage of alkaline stone in asphalt pavement in China ’s expressway construction,this study evaluated the improvement effects of schemes,including single use of amine anti-stripping agent DRD-K 1,single use of non-amine anti-stripping agent AMR- 3,single use of cement,and combined use of anti-stripping agent and cement,on the asphalt-aggregate adhesion properties.Through the tests of three major indexes before and after asphalt aging,aggregate adhesion test,and improved water immersion method,the adhesion of asphalt was evaluated,and the optimal amount for use was proposed.The results show that the non-amine anti-stripping agent AMR- 3 …

Factors Influencing Fatigue Damage In Manufactured Sand-Based Ecological Self-Compacting Concrete Pavement, Fu Suanzi, Li Hongyan

Journal of China & Foreign Highway

Ecological-self-compacting concrete (Eco-SCC ) pavements offer advantages such as reduced cement consumption,lower carbon emissions,and improved economic performance.However,their durability has not been sufficiently studied.Based on the literature review and fatigue test data,the fatigue parameters of Eco-SCC were determined using the Chaboche damage evolution model.A finite element model of fatigue damage in Eco-SCC pavement structures was established to compare the fatigue damage distribution under different loading positions,identify the unfavorable loading positions,and analyze the influence of slab thickness and modulus on the durability of Eco-SCC pavements.SCC plate thickness and modulus on the durability of Eco-SCC pavement.The results show that fatigue damage under different …

Adhesion Mechanism Of Geopolymer-Modified Emulsified Asphalt Slurry At Interface With Aggregate, Zhong Chao, Yang Hao, Lin Juntao, Xiao Yue

Journal of China & Foreign Highway

In order to investigate the adhesion mechanism at the interface between geopolymer-modified emulsified asphalt slurry and aggregate,the interfacial adhesion performance was studied by the molecular dynamics method and compared with that of cement-modified emulsified asphalt slurry.In addition,macro-scale splitting strength tests were performed for verification.The results indicate that van der Waals forces play a major role in the adhesion at the slurry-aggregate interface.Under equivalent mix ratios,the interfacial binding energy between the geopolymer-modified emulsified asphalt slurry and aggregate is 6.84% ‒19.99% higher than that of the cement system.The adhesion performance is closely related to the diffusion properties and atomic distribution of the …

Experimental Study On Workability Of Alkali-Activated Red Mud-Based Controlled Low-Strength Materials, Wu Yun, Fang Mingjing², Lin Zhiyang², Liu Zhengwei³, Beng Jianping³

Journal of China & Foreign Highway

This study aims to optimize the mix design of alkali-activated red mud-based controlled low-strength materials (CLSMs ) to enhance their applicability in road engineering backfilling.The effects of red mud content (20% ‒ 50%),water-to-solid ratio (0.30‒0.36),sand-to-soil ratio (7∶3‒4∶6),polycarboxylate superplasticizer (PEC ) dosage (0%‒2.1%),and fly ash to mineral powder ratio (5∶1‒0.5∶1) on the flowability and bleeding resistance of the materials were systematically investigated.The results are as follows:① The water-to-solid ratio significantly influences flowability.Increasing it to 0.32‒0.34 improves flowability by 39%‒78%,but when the ratio exceeds 0.34,the bleeding rate increases significantly (up to 4.89%);② When the red mud content is 30%‒40%,the high specific surface …

Damage Localization Of Simp Ly Supported Beams Based On Deflection Influence Surfaces Calculated By Three-Dimensional Boundary Face Method, Yin Xinfeng, Luo Zonghao, Yan Wanli, Kaiersaer ∙Tuerdi

Journal of China & Foreign Highway

The deflection influence surface (DIS) of a spatial structure is difficult to calculate using the existing two-dimensional boundary element method.To address this issue,a damage localization method based on DIS calculated using the three-dimensional boundary face method (BFM ) was proposed.A custom BFM program with an internal loop was developed,and the internal forces and deformations of a square plate and a supported T-beam structure were calculated using the static method.By specifying the domain of the order of a bivariate polynomial function (BPF ),a secondary optimization program for influence surfaces was established,and the DIS with the minimum mean square error was obtained.The …

Research On Construction Monitoring Of Continuous Rigid Frame Bridge Based On Knn Algorithm, Liu Jianlin, Pan Kai, Yang Gang, Wang Junming

Journal of China & Foreign Highway

To address common issues in bridge construction monitoring,such as sensor damage and failure in strain and displacement measurements,this study took the Nanliu Jialing River Bridge as a case and proposed a method based on the K-nearest neighbor (KNN ) algorithm to reconstruct missing construction monitoring data.ANSYS Workbench was used to establish a finite element model (FEM ) of the bridge construction process to verify the effectiveness of the KNN algorithm in the presence of missing bridge construction monitoring data.The results show:① KNN algorithm can assist in filling short-term data gaps caused by damage to strain and displacement sensors during bridge …

Shear Strength Test Of Uhpc-Nc Bonding Surface, Zhang Shichang, Yan Donghuang, Liu Yun, Yuan Sheng, Wang Shuo

Journal of China & Foreign Highway

As a cement-based composite material with excellent mechanical properties,ultra-high performance concrete (UHPC ) demonstrates outstanding performance in tensile and compressive strength,durability,and impermeability.This material is suitable for the reinforcement and repair of normal concrete (NC) bridge structures.To study the shear behavior of the UHPC-NC bonding interface and its reinforcement effect,this paper conducted interface shear tests using Z-shaped specimens and designed a total of six sets of comparative specimens.The influence of parameters such as the planted bar ratio,implantation depth,and bonding surface size on the shear strength was explored.Through experiments,the load –slip curve and the shear strength data were obtained.The results show that:① …

Field Measurement And Analysis Of Wind Characteristics At Xuefenghu Bridge Site, Yu Wenhao, Yi Lu

Journal of China & Foreign Highway

Wind field parameters at bridge sites serve as an important basis for wind-resistant bridge design.The terrain surrounding the Xuefenghu Bridge is unique-mountains flank both sides in the bridge-aligned direction,and the bridge spans the wide surface of the Zhexi Reservoir.In order to investigate the wind field characteristics under such complex topographic conditions,an observation,acquisition,and wireless data transmission system was established at the bridge site.A one-year in-situ wind measurement campaign was conducted,and the characteristics of average wind and fluctuating wind were deeply analyzed.The results show that the average wind speed at the bridge site generally follows a Weibull distribution,and the average wind direction …

Experimental Study On Shear Resistance Of Existing Prestressed Concrete Hollow Slabs, Lu Youfu, Di Jin, Qin Fengjiang, Sun Yifei

Journal of China & Foreign Highway

Prestressed concrete hollow slabs are widely used in small- and medium-sized span highway bridges in China.With the increase in load ratings,many hollow slab bridges built in early periods fail to meet the current specifications for shear bearing capacity.Nevertheless,these hollow slabs continue to function adequately under existing vehicle loads,making it essential to conduct an in-depth investigation into their shear bearing capacity.Shear bearing capacity tests were conducted on five 16 m-span hollow slabs dismantled from a renovation and expansion project,including three top slabs with a 15 cm cast-in-place concrete structural layer.Various parameters,such as load-displacement curves,web concrete strain,cracking loads,crack development patterns,failure modes,and ultimate …

Analysis Of Flexural Bearin G Ca Pacity Of Concrete Box Girders Reinforced With, Cfrp Mesh End Anchorshu Guihua

Journal of China & Foreign Highway

Carb on fiber reinforced polymer (CFRP ) composite s have significant advantages in the reinforcement of concrete structures.It is worth systematically studying the effect and mechanism of applying this material in embedded end-anchored reinforcement of concrete box girders on improving the load-bearing capacity of the component.Based on the Abaqus finite element analysis (FEA ) platform,two numerical analysis models considering slip contact and full bonding contact between CFRP mesh and polymer mortar were established.A full-scale concrete box girder model test was conducted for validation.The results show that the FEA results are in good agreement with the experimental results.The FEA model that …

Wind Tunnel Test On Wind-Resistant Performance Of Suspended Monorail Cable-Stayed Bridge, Chen Yujiang

Journal of China & Foreign Highway

To investigate the wind-induced vibration of a suspended monorail bridge,a full-bridge aeroelastic model at a 1∶40 scale was designed and fabricated according to the geometrical parameters and dynamic characteristics of the real bridge.Wind tunnel tests on the bridge in both the completed state and the maximum cantilever state were conducted under different conditions,including uniform flow and turbulent flow,yaw angles of ± 45°,±30°,±15°,and 0°,and wind attack angles of ‒ 3°,0°,and + 3°.Both vertical and torsional displacements of the structure under different wind speeds were measured.The test results show that the vertical displacements and torsional responses of the cable-stayed bridge increase when …

Research On Autonomous Deviation Correction Of Tunnel Boring Machines And Parameters Based On Machine Learning, Zhang Jun, Li Maopeng

Journal of China & Foreign Highway

In order to solve the problem of realizing the autonomous deviation correction of tunnel boring machines (TBMs ), a TBM deviation correction control method that integrated the random forest (RF) algorithm with the genetic algorithm (GA) was proposed based on actual engineering data.The method combined a prediction model with an optimization model,using target deviation values as input to invert and output the required TBM deviation correction parameter values,thereby further improving the automation level of TBM deviation correction.By comparing it with the actual data,the feasibility of the model was verified.The results show that the RF algorithm-based prediction model achieves an R2 …

Study On Mechanical Effect Of Backfill Construction In Orthogonal Underpass Section Of An Open-Cut Interchange Tunnel, Li Qingda, Li Dexing, Yu Tingshun, Han Xi, Liu Jiansong

Journal of China & Foreign Highway

This study investigated the mechanical effects of backfill construction in the orthogonal underpass section of a full-section complex open-cut interchange tunnel.The research was based on the small-clear-distance interchange tunnel project at the extension section of Jinzhou Avenue and Xingguang Avenue in Chongqing.A combined approach of numerical simulation and on-site in-situ test measurement was adopted to analyze the influence of different backfill materials,tunnel cross-section types,and complex construction procedures on the mechanical behavior of the underpass tunnel.The mechanical effects of backfill construction in the orthogonal underpass section were determined.The following findings are revealed:During the backfill construction process,the displacement and internal force of …

Research On Automatic Review Method Of Highway Bim Based On Knowledge Graph, Wang Wuyu, Shao Kebo, Zhang Feng

Journal of China & Foreign Highway

Building information modeling (BIM ),characterized by multi-dimensional modeling and multi-source data integration,is becoming a key technology to promote the innovation and digital transformation of the highway design industry.Taking BIM as the design deliverable is an inevitable trend in the future development of highway engineering design.However,the current highway BIM review is mainly conducted manually,which brings about problems such as low efficiency,susceptibility to errors,and high subjectivity.This makes it difficult to adapt to the review requirements of the three-dimensional (3D) digital design mode.To this end,this study proposed an automatic review method of highway BIM based on a knowledge graph.By constructing the knowledge graph …

Research On Multi-Classification Prediction Of Traffic Accident Severity On Mountainous Expressways, Wang Hao, Yan Jie, Guo Jianmin, Zhang Yu, Sun Chengji

Journal of China & Foreign Highway

To enhance the safety level of mountainous expressways and establish an accurate and effective prediction model for traffic accident severity,this study analyzed 2 484 traffic accidents on mountainous expressways in Chongqing from 2010 to 2016.A total of 17 influencing factors were selected from four aspects:human,vehicle,road,and environment,to serve as explanatory variables.Partial proportional odds model,random forest algorithm,and XGBoost algorithm were used to construct multi-class prediction models for traffic accident severity.The model performance was evaluated using the confusion matrix,accuracy,and minority class recall rate.The results show that the XGBoost model achieves the highest prediction accuracy in multi-class prediction of traffic accident severity on mountainous …

Application And Analysis Of Energy-Conservation And Carbon-Reduction Technologies In Green Highways, Huang Xuewen, Wang Kai, Huang Shanqian, Xiong Xinzhu, Fu Jinsheng

Journal of China & Foreign Highway

To improve the low-carbon development level of highway engineering,this study relied on a typical green highway in Anhui Province and established a calculation model for energy-conservation and carbon-reduction in highway engineering based on the emission factor method.A combination of quantitative and qualitative approaches was adopted to evaluate the benefits of 33 energy-conservation and carbon-reduction technologies in reducing life cycle energy consumption and carbon emissions,based on life cycle assessment (LCA ) theory.The results show that during the material production stage,through channel resource coordination and the application of low-carbon,energy-saving materials,comprehensive reductions in the embodied carbon can be achieved.During the construction stage,energy consumption …

Reference And Inspi Ration From Low-Carbon Development Experience Of Foreign Highway Infrastructure, Lu Chunying, Gao Shuohan, Du Xueyua N, Jian Li, Wang Xinjun, Kong Yaping

Journal of China & Foreign Highway

In order to provide supp ort for the scie ntific formulation of low-carbon highway infrastructure development policies in China,empirical analysis,comparative analysis,and other methods were utilized,and the construction goals and action strategies of low-carbon highway infrastructure in the United Kingdom,the United States,and Australia were sorted out.Advanced experience in the development of low-carbon highways abroad was summarized.On this basis,combined with the current situation and existing problems of low-carbon development of China ’s highway infrastructure,the following countermeasures and suggestions were proposed:① strengthening top-level design and formulating low-carbon development goals and paths;② implementing the concept of life cycle and strengthening the research and promotion …

Analysis And Control Of Impact Of Wide Waterway Excavation On Adjacent Bridge Pile Foundations, Zhang Peisheng, Qiao Lyu, Sheng Jianchao, Sheng Haoxiang, Liu Hanchen, Wang Zhe

Journal of China & Foreign Highway

When excavating a waterway beneath an existing bridge,the pile foundations are subjected to unloading from excavation and the loading from the superstructure,which may lead to excessive displacement and potential safety hazards.Based on the underpass project of the Desheng Expressway Bridge along the Zhejiang section of the Beijing ‒ Hangzhou Canal,this study established a three-dimensional finite element model (FEM ) and combined it with field monitoring to investigate the impact of wide waterway excavation on adjacent bridge pile foundations and corresponding control measures.A novel combined control method involving a retaining wall with supporting piles and fully enclosed isolation piles was proposed.The …

Influence Of Horizontal Curve Radius On Vehicle Fuel Consumption And Pollutant Emissions On Tw O-Lane Highways, Tu Shengwen, Lei Meimei, Guo Wenyu

Journal of China & Foreign Highway

To investigate the influence of horizontal curve radius on vehicle fuel consumption and pollutant emissions on two-lane highways,this study developed a model based on running speed theory,vehicle driving dynamics,and a fuel consumption and emission analysis system.Fuel consumption and emissions of CO2,CO,HC,and NOx were calculated for a passenger car traveling along horizontal curves under three design speeds:40 km/h,60 km/h,and 80 km/h.The results show that the horizontal curve radius has a significant effect on vehicle fuel consumption and pollutant emissions.The trends of fuel consumption,CO2,and NOx emissions vary consistently with curve radius,while CO and HC emissions follow a similar but different trend.At the …

Demystifying The Discharge Coefficient For Flow Over Thin Weirs And Sills, Joseph E. Pugh, Subhas Karan Venayagamoorthy, Timothy K. Gates

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A revised derivation of the discharge coefficient for flows over thin weirs and sills in the limits of wall overflow to a free overfall is given. Using dimensional analysis, we show that the discharge coefficient, (Formula presented), in the classical weir-discharge equation is best understood as a weir Froude number, (Formula presented), which accounts for the combined effects of inertia, contraction and viscous energy losses within the flow field. A comprehensive set of experimental data from historical studies is complimented by new data from the authors, featuring both laboratory flume experiments and three-dimensional numerical simulations of weir flows. Synthesis of …

Thermo-Mechanical Advancements For Very High Strength And Ultra High Performance Concretes, Lana Grayson Brown Sisung

Theses and Dissertations

Interest in the use of high-strength concrete (HSC) has increased in recent years with demand for improved concrete performance. HSCs are widely associated with high heat of hydration and elusive behavior when exposed to high temperatures commonly occurring in mass structures. The optimization of HSC mixture proportioning is difficult due to a wide variety of constituents that influence thermal and mechanical properties. Additionally, determining in-place properties of mass concrete placements is elusive, and there are currently minimal to no test methods available that are both predictive and a direct measurement of mechanical properties. The objective of this dissertation is to …

Localized Multivariate Statistical Assessment Of United States Construction Labor Shortages, Ahmed Shiha, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Craft labor shortage is a persistent challenge facing the construction industry across various markets. The historically low geographic mobility of construction labor exacerbates and localizes labor shortages. Several research efforts relied on subjective evaluations to quantify the existence of labor shortages on a national level. As such, there is a lack of empirical quantification of labor shortages at different geospatial levels. This paper fills this knowledge gap. To this end, the authors adopted a methodology that encompassed: (1) conducting a literature review to identify and collect national-level and subnational indicators that explain the changes in labor supply and demand; (2) …

Life Cycle Assessment Of The Cultivation Of Lettuce In A Hydroponic System Using The Nutrient Film Technique, Raquel Jordan

All Theses

Hydroponic systems are an emerging method of soilless crop cultivation typically done inside a greenhouse where nutrients are delivered dissolved in water rather than being supplied from the soil. Potential benefits of hydroponic systems include reduced irrigation requirements, higher crop yield per area, and the ability to grow crops year-round in nontraditional areas such as urban settings, cold climates, and sites with contaminated soil. However, hydroponic systems tend to have high energy requirements for lighting and climate control, which can yield significant environmental impacts. To explore the environmental impacts of cultivating lettuce in a nutrient film technique (NFT) hydroponic system, …

Evaluation Of Performance Characteristics And Groundwater Contamination Risks Associated With On-Farm Swine Carcass Disposal Via Composting And Shallow Burial With Carbon, Gustavo Castro Garcia

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation evaluates the performance of three on-farm swine carcass disposal methods: whole carcass composting (WCC), ground carcass composting (GCC), and shallow burial with carbon (SBC), focusing on biosecurity factors and groundwater contamination risks. Foreign animal diseases (FADs), such as African swine fever and classical swine fever, pose severe economic and animal well-being risks if introduced to the United States. With confirmation of an FAD, swine movement will be halted, creating an urgent need for practical, biosecure, and environmentally responsible on-farm disposal strategies for swine carcasses. Nebraska, as a leading swine-producing state, exemplifies the vulnerability of high-density livestock regions to …

Resilience Of Interdependent Transportation And Healthcare Systems: A Simulation-Driven Framework Incorporating Social Equity And Facility Optimization, S. Yasaman Ahmadi

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The overarching goal of this dissertation is to develop an integrated, simulation-driven framework to assess and enhance the resilience of interdependent transportation and healthcare systems before, during, and after natural hazards. By examining how spatial disruptions, social vulnerability, operational constraints, and infrastructure interdependencies affect access to and functionality of hospitals, this research offers a multifaceted evaluation of system performance under stress. This dissertation examines the impact of natural hazards, particularly floods, on the interdependent transportation and healthcare systems. The proposed approach combines and advances GIS-based network analysis, graph-theoretical modeling, and discrete-event simulation to evaluate system performance under different scenarios. The …

Wires, Roads, And Real-World Challenges: An Interdisciplinary Case Study Bridging Roadway And Electric Utility Design, Juliann A. Lloyd

All Theses

Electric utilities are a foundational component of modern society and depend heavily on civil engineers for planning, design, construction, and maintenance. However, educational content related to this industry is often underrepresented in civil engineering programs. To bridge this gap, a case study activity was implemented in two transportation engineering courses at Clemson University. The case study introduced students to the integration between electric utility infrastructure and roadway design by simulating a realistic and common conflict scenario faced by Departments of Transportation (DOTs) nationwide.

Students were placed in interdisciplinary teams, with each member assigned a specialized role such as Land Agent, …

Sensitivity Analysis Of Flexible Pavement For South Carolina Conditions, Shilpa Girish

All Dissertations

The objective of the study was to evaluate the sensitivity of various input variables on the flexible pavement design thickness of high-speed, high-traffic routes in South Carolina using the Mechanistic-Empirical Pavement Design Guide (MEPDG) by means of the AASHTOWare Pavement ME Design software using global calibration coefficients with a focus on bottom-up fatigue cracking. The variables considered in this investigation included two-way average annual daily truck traffic (AADTT), asphalt mix type, climate station, subgrade type and resilient modulus, and aggregate base thickness. The study includes comparative analysis using older methods like the AASHTO 1993 method and the South Carolina DOT …

Drift Dynamics Of Early Life-Stage Invasive Carps, Saurav Karki

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Asian carp species pose significant ecological threats to North American freshwater systems due to their invasive nature and prolific reproduction. Their semi buoyant eggs develop while drifting downstream with the river current. Understanding early life-stage transport is therefore critical for predicting recruitment potential and guiding management efforts. Existing fluvial egg drift models, including those relying on 1-D hydraulics and fully 3-D CFD-based models, are either inadequate for complex braided rivers or too computationally demanding for large-scale application. The Platte River in Nebraska, characterized by wide, shallow, multi-threaded channels, is dominated by two-dimensional flow conditions, making a depth-averaged 2-D modeling approach …