Transportation Engineering Commons^™

Advances And Challenges In Nano-Modified Cementitious Composites: Mechanisms, Dispersion Strategies, And Impact On Mechanical Properties, Fatemeh Mohammadi Ghahsareh, Pengwei Guo, Nusrath Jaha, Yi Bao, Kamal H. Khayat, Weina Meng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Nanomaterials are increasingly utilized to enhance the mechanical properties, durability, and functionality of concrete materials but face challenges such as agglomeration and uneven dispersion in cementitious systems, which can offset the intended improvements. This paper reviews the advances and challenges associated with nano-modified cementitious composites, elucidating fundamental mechanisms and highlighting strategies for overcoming the challenges through experimental and computing techniques. The reviewed contents include (1) the classification of nanomaterials commonly used in cementitious systems and the mechanisms through which they enhance the mechanical properties of cementitious composites; (2) challenges of nanomaterials such as agglomeration in water, re-agglomeration in cementitious systems, …

The Rise In Height And Curb Weight Of The Top-Selling Vehicles In The United States From 1991 - 2025: Implications For Engineering Design And Vulnerable Road Users, Samuel L. Steinman-Friedman

Civil Engineering Theses

Road fatalities are higher in the United States than in other high-income regions. In 2024, 39,254 people died on roads in the United States compared to 19,940 in the European Union. These two regions have comparable exposure metrics, such as population size, roadway network length, and fatalities per mile traveled. Light trucks dominate the U.S. market, whereas hatchbacks are prevalent in Europe. The trendline of the average height and curb weight of the top-selling vehicles in the United States has increased by 0.24 inches and 23.52 pounds per year since 1991. The average 2025 top-selling U.S. passenger vehicle is 7.5 …

Concord Public Transportation Improvement Project, Jacob Holt

Honors Theses and Capstones

The capital city of Concord, New Hampshire, has been served by Concord Area Transit (CAT) since 1989. Despite continued population growth and economic development within the city, CAT’s fixed route bus system has remained unaltered since 2011. The purpose of this project is to rework the CAT system to provide service that better aligns with Concord resident’s current needs. A public survey was conducted to gather data regarding Concord resident’s needs, habits, and perception of the existing system, which was used in the development of the revised system. The project includes suggestions for both system-wide and route-specific modifications. Key changes …

Statewide Corridor Evacuation Response And Re-Entry Behaviors In Florida During Hurricane Irma, Xin Wang, Yuan Zhu, Hong Yang, Kun Xie

Electrical & Computer Engineering Faculty Publications

Hurricane Irma stands as one of the most destructive tropical storms to make landfall in the United States, particularly impacting the State of Florida, where it prompted the largest evacuation in history with approximately 7 million residents. The profound consequences of mass evacuation underscore the critical need to understand travel behaviors during hurricane evacuation and the recovery process. This research analyzes statewide evacuation and re-entry patterns, leveraging diverse datasets, including TTMS data from main corridors and GIS data. A statewide corridor-based empirical analysis framework is constructed to characterize evacuation and re-entry response patterns using sensor-based traffic observations. The results show …

Enhancing Traffic State Estimation At Bottlenecks Through Improved Demand Modeling: A Greenshields-Grounded Approach, Yuyan Annie Pan, Xianbiao Hu, Qing Tang, Yanyan Chen, Xuesong (Simon) Zhou

Civil & Environmental Engineering Faculty Publications

Accurate estimation of traffic state under oversaturated conditions is fundamental to a wide range of transportation applications. While intuitive, volume-to-capacity (q/qc) ratio-based link performance functions (LPF) are challenged by the U-shaped pattern of real-world speed-flow plots, which contradict the monotonic assumptions of link performance models such as the Bureau of Public Roads (BPR) function, particularly when q/q_c ≥ 1. This study addresses this critical gap by proposing an enhanced demand estimation method grounded in the Greenshields model, incorporating a real-time inflow correction factor to more accurately capture traffic demand at bottlenecks. In parallel, a modified LPF is introduced, replacing …

Workshop Outcomes Report: 2nd International Workshop On Seismic Resilience Of Arctic Infrastructure And Social Systems, Majid Ghayoomi, Daniela Morganti

Faculty Publications

The report provides an overview of the second international workshop on Seismic Resilience of Arctic Infrastructure and Social Systems. The report discusses agenda, workshop activities, interdisciplinary working groups, and results. It ends with several strategic questions and investigation plans that were developed as part of the workshop activities.

Integrated Corridor Management Framework For Severe Freeway Incidents, Sanjida Afroz Iqra

Graduate Studies Theses and Dissertations 2026

Traffic incidents are a major source of non-recurrent congestion on urban freeways, generating substantial mobility, safety, and economic impacts. Severe incidents that block multiple or all travel lanes are particularly disruptive because they degrade freeway operations and propagate congestion onto surrounding arterials. Effective Integrated Corridor Management (ICM) requires the ability to identify severe incidents, estimate their network-wide impacts, and anticipate the traffic conditions and driver behaviors that contribute to instability. This dissertation develops a data-driven ICM framework to address these challenges using real-world incident, crash, detector, and connected vehicle data from major Central Florida corridors, including I-4 and SR-417. The …

Bond Behavior Of Uhpc-Nsc Interfaces For Bridge Deck Repair Under Flexural Loading, Larissa Santiago La Banca

Graduate Studies Theses and Dissertations 2026

The use of ultra-high performance concrete (UHPC) has increased due to its superior mechanical properties and strong bond with normal-strength concrete (NSC). It is widely used as a repair material, particularly in bridge decks, where maintenance remains a challenge. However, the interface between UHPC and NSC is often the weakest region of the composite system and requires careful evaluation.

This study investigates the bond behavior between UHPC and NSC using different surface preparations, test setups, and UHPC materials. The experimental program included unreinforced beams with vertical interfaces tested under three- and four-point flexural loading, and reinforced slabs with horizontal interfaces …

Predicting Safety And Mobility Parameters Based On Comprehensive Analytics Of Connected Vehicle Data, Lei Han

Graduate Studies Theses and Dissertations 2026

Traffic safety and mobility remain critical challenges for modern transportation systems. The emergence of connected vehicle (CV) data offers unprecedented opportunities to capture microscopic, non-aggregated driving dynamics to support precise and finer-grained traffic safety and mobility research. This dissertation develops a comprehensive CV data–driven analytical framework to advance traffic safety and mobility research across multiple roadway contexts, including intersections, segments, freeways, and urban arterial networks. For traffic safety, this research extracts both longitudinal and lateral risky driving behaviors from CV trajectories and integrates them with macro-level roadway, traffic, and visual environment features. A spatial machine learning framework is proposed for …

Smart Traffic Lights, Roa Ghanem

Student Scholar Symposium

Nashville is quickly growing, and as a result, traffic congestion is becoming a bigger challenge for commuters. Longer travel times and increased vehicle emissions are major concerns. This research examines how smart traffic lights can improve traffic flow and reduce congestion in the city. By analyzing peer-reviewed journal articles, this study explores how AI, IoT, and machine learning can optimize traffic signal timing in real time. In particular, simulation models illustrate how these technologies adapt dynamically to changing traffic patterns in cities similar to Nashville. Furthermore, this research compares the cost-effectiveness of smart traffic lights with other solutions, such as …

Curbless By Design: Revitalizing Downtown Infrastructure For Pedestrians, Alex Duran, Steve Cherry

Civil Engineering Professional Development Seminar

This presentation will discuss the design of a curbless, pedestrian-focused corridor as part of a small-town downtown reconstruction in Sylvania, Ohio. The project team will share how they balanced community goals, accessibility, and utility coordination, along with considerations for drainage, hardscape, lighting, and power. The session will also highlight early construction lessons learned from Phase 1.

Evaluating Tire-Pavement Noise Reduction Of Porous Asphalt Using Close Proximity Tests: Comparative Performance And Long-Term Effectiveness, Jin Hwan Kim, Kyungnam Kim, Oh Sun Kwon, Woo Young Cho, Youngguk Seo

Faculty Articles

The objective of this study was to understand the long-term noise reduction effect of Porous Asphalt (PA) in an expressway environment. To this end, PA was compared with that of Stone Mastic Asphalt (SMA), tined concrete, and Next-Generation Concrete Surface (NGCS) at the time of construction. Then, the evolution of PA’s acoustic performance was characterized on 82 pavement sections over the period of 1–18 years. The Close Proximity (CPX) method was used to measure tire-pavement noise at three cruising speeds: 80, 100, and 120 km/h. Mean Profile Depth (MPD) and permeability time were considered as key functional measures of PA …

Crack Propagation Behavior Of Polyurethane Grouting Sma Asphalt Mixtures, Ji Guoqi, Ma Hui, Zheng Junqiu, Huang Yujie

Journal of China & Foreign Highway

To reveal the influence me chanis m of polyurethane grouting on the crack propagation behavior of SMA-13 asphalt mixtures, this paper first conducted a semi-circular bending (SCB) test to validate the effectiveness of the PFC2D discrete element model, which was employed to simulate the microscopic responses of mixtures under different notch positions and grouting conditions. The analysis focused on load-displacement curves, crack propagation paths, crack number evolution, and force chain distribution characteristics. The results indicate that polyurethane grouting significantly increases the peak load and peak displacement of the specimens, thereby enhancing the fracture load-bearing capacity and deformation tolerance, with the …

Co2-Induced Changes In Rheology, Structural Evolution, And Particle Characteristics Of Cement Paste, Seongho Han, Tae Yong Shin, Seung Mo Kim, Jae Hong Kim, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The injection of carbon dioxide (CO₂) into cementitious systems has emerged as a promising approach to enhancing sustainability in concrete production. This study explores the impact of CO₂ injection on the rheological behavior, structural build-up, and particle size evolution of cement paste by systematically varying the water-to-cement ratio (w/c) (0.35, 0.4, and 0.5) and CO₂ concentration (0.06, 0.28, and 0.84 mol). Rheological analysis revealed a significant increase in initial yield stress with CO₂ injection. Using the Modified Bingham model, yield stress increased by 72 % and 150 % for 0.28- and 0.84-mol CO₂, …

Planning And Policy For Safer Roads With Autonomous Vehicles: Moral Decision Making Behavior In Dilemma-Inducing Situations, Fatemeh Nazari, Mohamadhossein Noruzoliaee

Civil Engineering Faculty Publications

This study develops a Dynamic Bayesian Network (DBN) framework to examine how public confidence in autonomous vehicle (AV) safety and willingness-to-ride respond to policy interventions in crash-imminent pedestrian–passenger prioritization scenarios. Using stated preferences survey data from San Francisco (SF) and San Antonio (SA), the model integrates baseline attitudes, socio-demographic factors, and policy conditions to simulate both intra-slice and inter-slice dependencies. Results from empirical-mix simulations indicate that SF respondents, despite having higher baseline confidence and willingness-to-ride, exhibit greater sensitivity to policies prioritizing pedestrians, with significant declines across all scenarios. By contrast, SA respondents show comparatively stable and modestly positive shifts, particularly …

Modeling Disaster Resilience Through A Human-Centered Lens: Exposure, Vulnerability And Adaptation, Tong Liu

All Dissertations

The core of reframing and operationalizing disaster resilience with a human-centered lens is to incorporate concepts from socio-ecological resilience into engineering resilience to better understand the humans’ capability for disaster adaptation. Existing studies have drawn practical implications by identifying actionable thresholds for infrastructure systems under disasters, which can be easily applied by policymakers, emergency managers and municipal agencies. However, how individuals interact with, respond to, or adapt under these infrastructure thresholds remain understudied. This hinders the operationalization of disaster resilience at the human scale.

First, I examined exposure by analyzing how configuration and distribution of urban infrastructure systems, such as …

Influence Of Mixing Duration And Absorption Characteristics Of Superabsorbent Polymers On The Fresh And Hardened Properties Of High-Performance Concrete, Yu Cun Gu, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigates the combined influence of superabsorbent polymers (SAPs) with distinct absorption kinetics and extended mixing sequences on the rheological, mechanical, and transport properties of high-performance concrete (HPC). Two SAPs—an ionic acrylamide-co-acrylic acid copolymer (SAP-P) and a non-ionic acrylamide polymer (SAP-B)—were incorporated at an internal curing level of 100%. The impact of extended mixing times (3, 5, and 7 min) following SAP addition was systematically evaluated. Results showed that longer mixing durations led to increased superplasticizer demand and higher plastic viscosity due to continued water absorption by SAPs. However, yield stress remained relatively stable owing to the dispersing effect …

Treatment And Activation Effects On Kaolinite-Based Earth Concrete, Mojtaba Kohandelnia, Maroua Zerzouri, Ammar Yahia, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-consolidating earth concrete (SCEC) addresses the long construction process of conventional earthen constructions and their structural limitations, while further efforts are needed to enhance its sustainability. This study explores the development of a kaolinite-based self-consolidating earth paste (SCEP) due to their blended powder system, incorporating raw and treated (calcined and ground-calcined) kaolinite under various activation techniques, such as water hydration, sodium hexametaphosphate (NaHMP), and sodium hydroxide (NaOH) activation. The synergistic effect of calcination and mechanosynthesis on rheological, mechanical, structural, and microstructural properties of SCEP were investigated. Mechanically treated kaolinite increased yield stress, plastic viscosity, storage modulus evolution, and build-up index, …

Evaluation Of The Effects Of Various Types Of Inert And Active Fillers On Asphalt Mixture Performance, Mohammad Hadizadeh Pirbasti

LSU Master's Theses

Abstract:

The performance of asphalt mixtures is significantly influenced by the type and characteristics of fillers used as a replacement for filler part of the aggregates’ batching. According to this research investigation the performance along with durability characteristics of asphalt mixtures are evaluated through different inert and active fillers. The fillers used include Fly Ash, Cement, steel slag powder, and additional filler. These fillers incorporate into two types of asphalt mix design of Stone Matrix Asphalt (SMA) and a surface mix. Fillers are categorized according to their reactive properties alongside their physical attributes leading to active fillers strengthening bond formation …

Airfield Pavement Management Framework Using Advanced Modeling Techniques, Heena Dhasmana, Marwa Hassan, Elise Mansour

Publications

Airport authorities constantly collect pavement condition data and utilize life-cycle cost analysis to select construction and maintenance alternatives. The current Federal Aviation Administration (FAA) Advisory Circular 150/5380-7B recommends using Pavement Condition Index (PCI) to assess airfield pavement condition for planning of Maintenance and Rehabilitation (M&R) treatments. However, structural and functional performance might not be fairly represented by solely one indicator, the PCI. The latter might mask the root cause of the pavement deterioration and lead to inadequate M&R recommendations. Furthermore, the regression nature of the existing airfield pavement assessment models is not adequate for establishing pavement performance prediction as a …

Optimizing The Sustainability Of Asphalt Pavements Through Incorporating Crumb Rubber In High-Modulus Asphalt Concrete (Hmac) Mixtures In Louisiana, Heena Dhasmana, Marwa Hassan, Mohamed Abdelmageed

Publications

Asphalt mixtures are traditionally produced using the Superpave mix design method, which emphasizes volumetric properties; however, current research is shifting toward performance-based and sustainable approaches. Within this context, the French High Modulus Asphalt Concrete (HMAC) design focuses on achieving specific performance criteria for workability, stiffness, rutting resistance, and fatigue behavior, employing a hard binder with higher asphalt content and fewer air voids than Superpave mixes. In this study, HMAC mixtures were developed using crumb rubber and locally sourced Louisiana materials. Five HMAC mixes using PG 76-22 and PG 67-22 binders with 10% and 20% crumb rubber were prepared, along with …

Hickory Street Square Revitalization, Spencer Knight, Grace Dungan, Tim Kula, Evan Lauritsen, Lindsey Mennenga

Honors Program: Senior Projects (Public)

The Hickory Street Square Revitalization Project seeks to transform a central public space in Sidney, Nebraska into a dynamic, community-oriented area that supports local events, economic activity, and cultural heritage. The project addresses six core objectives: 1) convertible street design, 2) parking lot reconfiguration, 3) public amenities, 4) event flexibility, 5) lighting and signage, and 6) old electric plant renovation. A conceptual design was developed by the design team (S.T.E.E.L. Sentinel Solutions) by synthesizing the most effective features of three preliminary alternatives, shaped further through community feedback and evolving project constraints. The final project design minimizes disruption to existing activity …

Comparison And Evaluation Of Overlay And Leveling Binder In Traffic Circle Construction, Pratik Neupane

Graduate Theses and Dissertations (2019 - present)

Traffic circles play a vital role in managing traffic flow and ensuring safety, yet their unique traffic conditions make them prone to early cracking and deformation. This study evaluated the performance of overlay and leveling binder asphalt mixtures for a reconstructed traffic circle at the University of South Alabama, using plant-mixed laboratory-compacted (PMLC) specimens. Volumetric analyses were performed to determine maximum specific gravity (Gmm), bulk specific gravity (Gmb), and air voids content. Laboratory tests were conducted on both the overlay and leveling binder layers using indirect tensile cracking test (IDEAL-CT) and indirect tensile rutting test (IDEAL-RT) to assess cracking tolerance …

Incorporating Recycled And Repurposed Plastic Into 100% Reclaimed Asphalt Pavement, Basant Bhatt

Graduate Theses and Dissertations (2019 - present)

The increasing awareness of sustainability in the asphalt industry has driven the use of recycled materials like reclaimed asphalt pavement (RAP) and waste plastic. This study examines the incorporation of recycled polypropylene (rPP), recycled high-density polyethylene (rHDPE), and recycled low-density polyethylene (rLDPE) at 0.3%, 0.6%, and 0.8% dosages into 100% RAP, along with the warm mix asphalt additive Evotherm® P25. Laboratory tests were conducted to evaluate the mechanical and durability performance of the modified asphalt mixtures while rutting and fatigue life were evaluated using mechanistic-empirical (ME) analysis in PerRoad software. Both plastic type and dosage had a statistically significant impact …

Enhancing Asphalt Mix Design Through Film Thickness And Bailey’S Gradation Method, Lydia Quinn

Civil Engineering Undergraduate Honors Theses

Contemporary asphalt research aims to strike a balance between rutting and fatigue cracking to enhance pavement longevity. The performance of asphalt mixtures is influenced by factors such as aggregate gradation and asphalt film thickness. Although gradation typically adheres to the mid-gradation method, asphalt film thickness is included in certain mix designs, even though it is not universally regarded as an essential parameter. Nonetheless, no current method primarily addresses both gradation and asphalt film thickness together. In this research, aggregate gradations were designed using the principles of Bailey’s method along with various other criteria such as control points, the dust to …

A Statistical Investigation Of The Parameters Influencing Rutting And Cracking Performance In Asphalt Mixtures, Alexis Light

Civil Engineering Undergraduate Honors Theses

Durable pavement is essential for modern transportation infrastructure, especially in the United States of America which boasts over 8.5 million lane miles of roads and highways. Despite advanced construction techniques, asphalt pavements are susceptible to rutting and cracking, significantly affecting their performance and maintenance costs. Current methods for analyzing rutting and cracking in asphalt mixtures rely on various parameters, leading to measurement variability. This highlights the need for more rigorous analysis to explore the relationship between mix design variables and pavement performance. This research explores the IDEAL-CT and APA data from 171 mix designs collected by the Arkansas Department of …

Mash Crashworthiness Of Work Zone Devices And Breakaway Luminaire Poles, Mohammadreza Rajaee

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

This thesis presents a study on the crashworthiness of two commonly-used roadside safety devices: Type II barricades and luminaire poles supported by TB1-17 transformer bases. The first part focuses on designing and evaluating a non-proprietary, Type II barricade that meets MASH criteria. A validated LS-DYNA model, based on a previously-tested Type III barricade, was used to guide the design. The proposed Type II system was evaluated through simulation and confirmed with full-scale crash testing. The second part of the study investigates luminaire poles supported by the TB1-17 transformer base. A previously-developed LS-DYNA model was updated and validated using test No. …

Development Of Timber Bridge Railing And Approach Guardrail Transition, Aaron Lechtenberger

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

Timber bridges with transverse and longitudinal bridge decks are increasingly utilized across the United States. However, limited research exists to develop bridge railing systems for high-service-level roadways that meet current vehicular impact safety standards. In response to this gap, the United States Department of Agriculture - Forest Service -Forest Products Laboratory (USDA-FS-FPL), in collaboration with the Midwest Roadside Safety Facility (MwRSF), initiated a research program to develop, crash test, and evaluate higher-service-level bridge railings and approach guardrail transitions (AGTs) compliant with the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH).

This study continued …

Comparative Analysis On Design Error Risks In Design-Bid-Build And Design-Build Construction Approaches, Eradius Edward Rwakarehe

Tanzania Journal of Engineering and Technology (TJET)

This study was conducted to compare design errors risk in Design-Bid-Build (DBB) (traditional) and Design-Build (DB) methods in building projects. Several construction projects under both DB and DBB method were reviewed. On most of construction projects under DB method, it was found that there were over supply of floor area due to different reasons. Also, it was found that, clients’ requirements were changed during project execution, which resulted into change on schedule, contract value and project quality. It was also revealed that in most cases, designs were in accordance with the clients’ requirements as submitted earlier but during construction clients …

Pros And Cons Of Preservation Treatments, Buzz Powell

Local Transportation Asset Management Conference

No abstract provided.