Civil Engineering Commons^™

Enhancing Concrete Sustainability With Self-Healing Technologies, Al Shimaa Abdullatif

Theses and Dissertations

Thanks to its strength, durability and affordability, Portland cement concrete is the most commonly used building material worldwide. However, concrete cracking is inevitable due to numerous factors including shrinkage, exposure to external chemicals, internals reactions, excessive loads, to name but a few. Self-healing is a promising technique that can enable concrete to autogenously heal cracks and alleviate much of the damage. Such healing can without a doubt extend the service life with less need for external repair works therefore it contributes to sustainability. Over the years, several means of self-healing agents have been explored including bio-based procedures and the incorporation …

The State Of The City's Bridges, Leo G. Miranda

Capstones

An analysis by NYCity News Service of 2024 federal bridge inspection found that 118 segments of city bridges are in poor condition, around 8% of all bridges citywide. Among these are segments of major highways and bridges like the Brooklyn Queens Expressway, FDR Drive, Harlem River Drive, Grand Central Parkway and even a part of the iconic Brooklyn Bridge. On a single stretch of highway, where the Grand Central Parkway and the Whitestone Expressway meet in Queens, there are seven parts of highway or ramps in poor condition.

Bridge segments can be any raised roadway that passes over another parkway, …

A Case Against Exclusive Reliance On Volumetric Mixture Characterization For Future Asphalt Pavements And The Advancement Of A Viable Alternative, Jonathan Randy Easterling

Theses and Dissertations

Volumetric properties have been the cornerstone of asphalt mixture design and control dating back to the early 20th century. However, social and economic drivers have caused the asphalt industry to make changes in materials and processes used to produce mixtures that have stretched the limits of volumetric centric methodologies. The primary objectives of this dissertation were to present an extensive case on how volumetrics is limited in their ability to characterize asphalt mixtures and to advance the body of knowledge of a viable alternative. State agency specifications were examined and found that Departments of Transportation (DOTs) were using asphalt volumetric …

Assessing Plate Load Testing And Modulus Of Subgrade Reaction Determination For Pavements, Jami Lynn Rushing

Theses and Dissertations

This thesis aims to: 1) determine the effect of plate size on the modulus of subgrade reaction (k), 2) investigate the differences between the ASTM D1196-21 and CRD-C 655-95 plate load test methods, and 3) develop new effective k curves. 150 plate load tests were executed on three subgrade materials under varying base course thicknesses. Plate load testing was designed to evaluate various plate sizes and testing standards (e.g., the military standard – CRD-C 655-96 and the ASTM standard – ASTM D1196-21). By performing plate load tests on varying base course thicknesses, newly developed effective k curves were developed from …

The Plastics Crisis: Responsible Recycling In Civil Engineering And Infrastructure, Jason Howell Stewart

Theses and Dissertations

A global plastics crisis exists with around 400 million metric tons (MMT) of plastics production and 350 MMT of plastics waste generated annually around the globe. Plastics are durable and essentially non-biodegradable, so they accumulate in both terrestrial and marine environments as pollution and within landfills without breaking down over time. Plastics are ubiquitous in 21st-century society and culture, comprising essential elements in most industries including packaging, transportation, electrical/electronics, and building/construction. The role of civil engineering and infrastructure in addressing the plastics crisis was specifically explored. Responsible plastics recycling yields products with improved engineering properties, performance characteristics, marketability, and/or manufacturing …

Physics-Based And Data-Driven Constitutive Modeling Of Unsaturated Soils Under Multi-Physics Loading Conditions, Mohsen Ajdari

Theses and Dissertations

Understanding the behavior of unsaturated soils under multi-physics loading is crucial for addressing several challenges related to emerging geo-energy technologies, climate change, and geohazard mitigation. The main objective of this research is to enhance the state of the art for modeling unsaturated soils under multi-physics loading conditions through physics-based and data-driven approaches. Toward this objective, this dissertation is divided into two distinct yet interrelated parts. In the first part (Chapters 2, 3, and 4), thermodynamic principles are employed to develop new constitutive functions to describe soil suction and stress-dilatancy of unsaturated soils under temperature-dependent conditions. Building upon the insights gained …

Enhanced Wind Velocity Imputation Near Building Structures Using Advanced Machine Learning Techniques, Istiak Ahammed, Sujeen Song, Gang Hu, Jinwoo An, Bubryur Kim

Civil Engineering Faculty Publications

The evaluation of instantaneous wind flow patterns nearest to building architecture is crucial to ensuring structural stability, architectural integrity, and pedestrian safety. Particle image velocimetry (PIV), a technique for studying fluid flow by tracing particles, provides accurate predictions of instantaneous wind velocities (IWV). However, PIV encounters challenges in specific regions due to laser light-based experimentation, leading to missing data. Consequently, investigating the wind circulation pattern around buildings becomes more challenging. Numerous ML techniques have been employed to impute missing wind velocities at random building locations with minimal structural impact. This paper focuses on addressing this concern by utilizing a machine …

Enhancing Civil Infrastructure Performance Through Lidar-Based Dynamic Monitoring And Phased-Construction Bridges, Khalid Hossam Alkady

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

This dissertation aims to enhance the performance and structural integrity of civil infrastructure systems through two primary goals. The first goal is to develop and rigorously validate end-to-end frameworks for full-field monitoring of the dynamic response of civil structures via Ground-based Lidar (GBL) scanners. GBL can be employed to sample point clouds at a high sampling rate for dynamic data collection, which addresses the limitations of using contact-based sensors in structural health monitoring (SHM) applications used for early-detection of structural damage.

The second goal of this dissertation concerns the challenges associated with constructing bridges in phases, so they can remain …

Increasing Drift Capacity Of Non-Ductile Concrete Shear Walls Through Confinement With Fiber-Reinforced Polymer Application, Andrew Duong, Sophia Maglabe, Sheyna Rongong

Architectural Engineering: Graduate Reports

The seismic response and laboratory testing of pre-1980s reinforced concrete (RC) shear walls commonly exhibit undesirable concrete crushing and rebar buckling in the wall end-zones leading to a flexural compressive failure. The lack of ductility of these walls is attributed to low reinforcement ratios and absence of special boundary elements (SBE) as required by modern design code. Thus, the authors are proposing a fiber reinforced polymer (FRP) retrofit method to provide confinement to the end-zones of pre-1980s walls equivalent to that of an SBE. Current industry applications of FRP have largely been for shear strengthening of RC beams, columns, and …

Assessing The Effect Of Material Properties On Full Depth Reclamation (Fdr) Mixtures Via Compressive Strength Characterization, Toluwanimi Ogundipe

Graduate Theses and Dissertations

Enormous amounts of money to replace all poorly maintained roads with brand new construction or with rehabilitation options like the mill and overlay which neglects the address of underlying pavement issues. To reduce the cost intensity of new construction of dilapidated pavements, state departments of transportation are seeking cost-effective techniques to rehabilitate roads. One of the techniques that have been explored and implemented by state DOTs is full-depth reclamation. Full depth reclamation (FDR) as a pavement rehabilitation technique is the reclaiming and recycling of an existing pavement with a predetermined amount of existing base layer. The combination of the reclaimed …

Controlling Expansion Behavior Through Curing And Mix Design For An Expansive, Rapid-Setting Bcsa Cement, Amanda Parolini Dutra

Graduate Theses and Dissertations

Cracking in concrete has been a concern for engineers because it reduces its durability and strength. Some of this cracking behavior is due to shrinkage, which occurs when the water in the concrete evaporates and causes a reduction in volume. Expansive cements were invented to counteract this shrinkage behavior. This research studies a new formulation of a standalone, fast-setting, fast-strength gain expansive BCSA cement. Since it is a new cement, a limited amount of literature is available about mixture design, strength properties, and how to obtain the desired level of expansion. This study then aims to fill some of these …

Determination Of The Internal Erosion Potential Of Bcsa Soil-Cement Using A Modified Hole Erosion Test System, Edgar Enrique Ortega De La Cruz

Graduate Theses and Dissertations

Levees play a fundamental role in preserving human lives and resources and are the key infrastructure protecting against flood events. In the United States, the levee system is extensive, but unfortunately many of the levees were either not engineered or have well exceeded their intended design life. This was evident after the Midwest floods of 2019, which resulted in the failure of multiple levees leading to costly losses and repairs. In addition, flood levels remained high for days at a time, making it imperative to find fast and effective repair methods. This thesis presents a study conducted at the University …

Paste Properties, Hardened Concrete Properties, And Mix Design Process For Magnesium Phosphate Cement, Rilye Dillard

Graduate Theses and Dissertations

Magnesium phosphate cement (MPC) is a rapid-setting alternative cement typically used as a quick repair material. MPC has gained popularity in recent years due to its ability to reduce CO2 emissions, its strong chemical resistance, and potential use in large scale applications. There is currently limited research on the properties of MPC when varying the proportions of its ingredients. Several hardened concrete properties were analyzed on concrete mixtures made with MPC. A mix design process for MPC concrete is proposed based on testing of 300 MPC paste mixtures and 115 MPC concrete mixtures. A standardized mix design process is imperative …

An Investigation Into The Effect Of Performance Engineered Mixture (Pem) Design On The Workability And Strength Of Concrete Pavement Mixtures, Alexander Cook

Graduate Theses and Dissertations

The Arkansas Department of Transportation (ARDOT) currently requires a minimum cement content of 564 pounds of cement per cubic yard of concrete. This minimum cement requirement can be reduced through the utilization of optimized gradation of aggregates within concrete mixtures as well as the addition of supplementary cementitious materials (SCMs) such as fly ash. The study presented in this paper aims to demonstrate how the use of the Tarantula Curve can be used to design concrete mixtures with reduced cement contents while maintaining sufficient workability for concrete mixtures to be used for slipform paving. Fresh workability was measured using the …

Life-Cycle Cost Analysis Of Fm4 Txdot Roadway Alternatives In Cleburne, Texas, Ethan A. Bright

2024 Fall Honors Capstone Projects - Archive

The Engineering senior design group proposed a three-span concrete bridge, merged lane intersection, and a single storm conduit system. The Honors contribution to this project was analyzing the design’s alternative’s life-cycle costs to compare the most economic design. The project’s cost consists of initial construction, maintenance, and decommission. Utilizing Texas Department of Transportation (TxDOT) bid code unit prices, each design alternative is calculated by multiplying each material amount by the unit price then summed. Although the parallel conduit system has a cheaper initial cost, it requires more maintenance during its lifetime, therefore the single conduit system was recommended. Notably, cost …

A Strategic Insight Into The Market For Carbon Management Capacity, Mahelet G. Fikru, Ting Shen, Jennifer Brodmann, Hongyan Ma

Economics Faculty Research & Creative Works

This study presents the market for carbon management capacity via carbon capture, utilization, and storage technologies, identifying demand and supply forces, as well as clarifying the potential impact of market and non-market-based shocks on technology developers versus adopters. The paper addresses a prevailing gap in market analysis, introducing a microeconomic framework and unique dataset to identify key players, market forces, and policy incentives shaping the carbon capture, utilization, and storage landscape. The analysis equips industry stakeholders, policymakers, and investors with valuable insights regarding (1) leaders in the design, development, and manufacture of carbon capture, utilization, and storage technologies (supply), (2) …

Fitting Quality Of Nmr Relaxation Data To Differentiate Asphalt Binders, Rebecca M. Herndon, Kevin Lai, Magdy Abdelrahman, Klaus Woelk

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Asphalt binder performance grades (PGs) are important metrics in designing pavements for effective transportation infrastructure. the PG system relies on the binder's stiffness and is determined through energy- and time-intensive physical testing. Physical properties, like stiffness, can also be determined by spin–lattice NMR relaxometry, a non-destructive chemical method. NMR relaxometry can quantify the molecular mobility of materials by determining relaxation times from exponential decays of excited nuclear magnetization. While relaxation times have been used to determine physical properties of materials, a quantitative relation to the PG grades of asphalt binder is yet to be established. in this study, T1 NMR …

Impacts Of Stream Bed Adjustment On Local Bridge Morphology At Highway 281, Molly G. Likins

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

Nebraska sand-bed rivers have long been a part of sediment transport studies and have been used in the development of numerous well-known empirical bedload equations. Some of these studies have shown how adjustments in streambed elevation led to changes in local stream morphology. The sand-bed rivers of Nebraska are highly susceptible to such changes due to their wide, shallow cross-sections and erodibility. The objective of our study is to synthesize a hydrodynamic model with high-resolution field data and improved methods of representing sediment transport to better predict both short and long-term channel adjustments for an aggraded sand-bed river.

The field …

Development And Evaluation Of Highly Thixotropic Uhpc Mixtures For Bridge Overlay Applications, Akbota Aitbayeva

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

Ultra-high-performance concrete (UHPC) is an advanced construction material renowned for its exceptional strength and durability. However, conventional UHPC is typically self-consolidating, making it unsuitable for bridge deck overlay applications due to challenges posed by potential surface slopes. UHPC overlay construction requires a highly thixotropic material that not only responds well to vibration but also maintains workability over an extended period and remains stable on sloped surfaces. Despite the complex rheological properties of highly thixotropic UHPC, limited testing methods are available to effectively assess the workability and rheology of overlay mixtures. To address this gap, the present study provides a comprehensive …

Exploring Variably Saturated Flow Formulations For Modflow: Implementing A Fully 3d Richards' Equation In Modflow 6, Sebastian Vazquez-Gasty

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

This thesis explores the implementation of a fully 3D Richards’ equation solution into MODFLOW 6 to solve for saturated/unsaturated flow. Currently, MODFLOW 6 has limited capability for solving unsaturated zone flow problems by using the Unsaturated Zone Flow (UZF) package, which neglects capillarity and assumes vertical 1-dimensional flow. Various formulations of the Richards’ equation were first evaluated for their strengths and weaknesses. Various numerical solution approaches to Richards’ equation were also studied to understand the robustness and efficiency of different approaches and to select one that would best fit into the MODFLOW 6 framework. The MODFLOW 6 framework was also …