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Full-Text Articles in Architecture

Synergetic Effect Of Viscosity Modifying Admixtures And Polycarboxylate Ether Superplasticizer On Key Characteristics Of Thixotropic Uhpc For Bonded Bridge Deck Overlay Rehabilitation, Le Teng, Ming Jin, Jiadi Du, Kamal H. Khayat Jul 2024

Synergetic Effect Of Viscosity Modifying Admixtures And Polycarboxylate Ether Superplasticizer On Key Characteristics Of Thixotropic Uhpc For Bonded Bridge Deck Overlay Rehabilitation, Le Teng, Ming Jin, Jiadi Du, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Thin bonded ultra-high-performance concrete (UHPC) overlay is an advanced technology for bridge deck rehabilitation. UHPC should be tailored to secure adequate flowability and high thixotropy to facilitate mixing and placement with a low risk of sagging of the material on sloped bridge deck surfaces. The synergetic effect between nano clay (NC) and polycarboxylate ether (PCE) superplasticizer or cellulose-based viscosity modifying admixture (VMA) and PCE on the rheological properties (yield stress, plastic viscosity, and thixotropy), cement hydration, autogenous shrinkage, compressive strength, and porosity was systematically investigated. The bond strength between conventional concrete (CC) representing existing bridge deck concrete and thixotropic UHPC …


A Review Of Whipple Shield Ballistic Limit Equations, S. Ryan, W. (William) P. Schonberg May 2024

A Review Of Whipple Shield Ballistic Limit Equations, S. Ryan, W. (William) P. Schonberg

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Ballistic limit equations (BLEs) are semi-analytical expressions used to predict the risk posed by micrometeoroid and orbital debris (MMOD) impacts on a spacecraft. A foundational BLE, known as the new non-optimum (NNO) equation was published by Eric Christiansen of NASA Johnson Space Center in 1990 for application on Whipple shields – two-plate configurations consisting of a thin sacrificial plate located at some standoff in front of the spacecraft pressure hull or structural wall. Today, BLEs for almost all multi-plate spacecraft structures, e.g., honeycomb sandwich panels, monolithic structures with thermal insulation blankets, etc., are based on the NNO Whipple BLE. We …


Four-Way Cfd-Dem Coupling To Simulate Concrete Pipe Flow: Mechanism Of Formation Of Lubrication Layer, Tooran Tavangar, Masoud Hosseinpoor, Jeffrey S. Marshall, Ammar Yahia, Kamal H. Khayat May 2024

Four-Way Cfd-Dem Coupling To Simulate Concrete Pipe Flow: Mechanism Of Formation Of Lubrication Layer, Tooran Tavangar, Masoud Hosseinpoor, Jeffrey S. Marshall, Ammar Yahia, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study introduced a four-way CFD-DEM coupling approach to simulate the shear-induced particle migration (SIPM) mechanism leading to formation of the lubrication layer (LL) during concrete pumping. The CFD-DEM simulations considered the coupled effect of concentration (10 %–40 %) and wide size distribution (1–17 mm) of aggregate and rheology of the mortar for forces between the suspending matrix and the particles (and vice versa), as well as force transmission directly between particles (and the pipe wall). The formation of the LL was successfully simulated through a more realistic understanding the SIPM mechanism and rheological evaluation across the pipe with comparable …


Comprehensive Numerical Modeling Of Prestressed Girder Bridges Under Low-Velocity Impact, Mohamed T. Elshazli, Mohanad M. Abdulazeez, Mohamed Elgawady, Ahmed Ibrahim Mar 2024

Comprehensive Numerical Modeling Of Prestressed Girder Bridges Under Low-Velocity Impact, Mohamed T. Elshazli, Mohanad M. Abdulazeez, Mohamed Elgawady, Ahmed Ibrahim

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Accidental Collisions Involving Over-Height Trucks That Exceed Vertical Clearance Limits And Bridge Superstructures Frequently Happen, Resulting In Compromised Girders And Potential Threats To Structural Safety And Performance. The Numerical Simulation Of Large-Scale Prestressed Girder Bridge Collisions Poses Challenges Due To The Associated Nonlinearities, As Well As The Limited Availability Of Large-Scale Experimental Testing Data In The Literature Due To Cost And Complexity Constraints. This Study Introduces A Numerical Modeling Approach To Efficiently Capture The Response Of Prestressed Girder Bridges Under Lateral Impact Loads. A Finite Element (FE) Model Was Developed Using LS-DYNA And Meticulously Validated Against Experimental Data From The …


Methodology To Design Eco-Friendly Fiber-Reinforced Concrete For 3d Printing, Haodao Li, Alfred Addai-Nimoh, Eric Kreiger, Kamal H. Khayat Mar 2024

Methodology To Design Eco-Friendly Fiber-Reinforced Concrete For 3d Printing, Haodao Li, Alfred Addai-Nimoh, Eric Kreiger, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Greater use of locally available supplementary cementitious materials (SCM) to reduce cement content and addition of fiber reinforcement can enhance the performance of 3D printing (3DP) technology in construction. In this study, three classes of eco-friendly 3D printable fiber-reinforced mixtures were targeted, namely ultra-high-performance concrete (UHPC), high-performance concrete (HPC), and conventional concrete (CC). A step-by-step methodology was proposed to maximize the substitution rate of cement with SCM and limestone filler and optimize fiber volume for the successful development of 3D printable fiber-reinforced materials. Binder combinations were initially investigated on the paste level to determine the packing density and robustness. Selected …


Natural Gas Induced Vegetation Stress Identification And Discrimination From Hyperspectral Imaging For Pipeline Leakage Detection, Pengfei Ma, Ying Zhuo, Genda Chen, Joel G. Burken Mar 2024

Natural Gas Induced Vegetation Stress Identification And Discrimination From Hyperspectral Imaging For Pipeline Leakage Detection, Pengfei Ma, Ying Zhuo, Genda Chen, Joel G. Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Remote Sensing Detection of Natural Gas Leaks Remains Challenging When using Ground Vegetation Stress to Detect Underground Pipeline Leaks. Other Natural Stressors May Co-Present and Complicate Gas Leak Detection. This Study Explores the Feasibility of Identifying and Distinguishing Gas-Induced Stress from Other Natural Stresses by Analyzing the Hyperspectral Reflectance of Vegetation. the Effectiveness of This Discrimination is Assessed Across Three Distinct Spectral Ranges (VNIR, SWIR, and Full Spectra). Greenhouse Experiments Subjected Three Plant Species to Controlled Environmental Stressors, Including Gas Leakage, Salinity Impact, Heavy-Metal Contamination, and Drought Exposure. Spectral Curves Obtained from the Experiments Underwent Preprocessing Techniques Such as Standard …


Characterization Of Alkali-Silica Reaction (Asr) Products And C-S-H Using Swir Spectroscopy For Nondestructive Detection Of Asr, Pengfei Ma, Wenyu Liao, Ying Zhuo, Hongyan Ma, Yanping Zhu, Genda Chen Feb 2024

Characterization Of Alkali-Silica Reaction (Asr) Products And C-S-H Using Swir Spectroscopy For Nondestructive Detection Of Asr, Pengfei Ma, Wenyu Liao, Ying Zhuo, Hongyan Ma, Yanping Zhu, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study explores the feasibility of characterizing alkali-silica reaction (ASR) products and calcium silicate hydrates (C-S-H) from short-wave infrared (SWIR) spectroscopy. ASR products and C-S-H samples with different Ca/Si ratios were synthesized and analyzed through XRD, 29Si nuclei magnetic resonance (NMR) and SWIR spectroscopy. Fourier-transform infrared spectroscopy (FTIR) was collected to help interpret the results from the SWIR spectroscopy. The obtained spectroscopic features were applied to quantify the ASR product abundance denoted by the length expansion of mortar bars after an accelerated ASR test. The results show that the SWIR spectra of the synthetic ASR gels are similar regardless of …


Evolution Of Sbs-Modified Asphalt Performance Under Aging And Rejuvenation Cycle Conditions, Ke Shi, Feng Ma, Jenny Liu, Zhen Fu, Ruimeng Song, Dongdong Yuan, Aboudou Wassiou Ogbon Feb 2024

Evolution Of Sbs-Modified Asphalt Performance Under Aging And Rejuvenation Cycle Conditions, Ke Shi, Feng Ma, Jenny Liu, Zhen Fu, Ruimeng Song, Dongdong Yuan, Aboudou Wassiou Ogbon

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Improving the poor long-term service performance of rejuvenated SBS-modified asphalt (REF-LT) is highly challenging. In this study, a blend of aged and virgin binders was used to rejuvenate REF-LT and the evolution of the asphalt performance was observed during regeneration and reaging processes. An SBS-modified asphalt (SBM) and base asphalt (BA) were mixed with REF-LT in specified ratios to prepare SBM- and BA-rejuvenated asphalts. The rejuvenated asphalts were subjected to short- and long-term aging. The high/low-temperature rheological properties, fatigue resistance, rejuvenation mechanism, and changes in the functional groups of the rejuvenated and reaged asphalts were characterized using a dynamic shear …


Numerical And Experimental Investigation Of Negative Stiffness Beams And Honeycomb Structures, Yasser Darwish, Mohamed A. Elgawady Feb 2024

Numerical And Experimental Investigation Of Negative Stiffness Beams And Honeycomb Structures, Yasser Darwish, Mohamed A. Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Metamaterial structures that exhibit negative stiffness (MSNS) behavior have shown the potential to be used as energy dissipation systems in different applications. Negative stiffness honeycomb structures consist of multiple pre-buckled beams that snapping through from one pre-buckled mode to another buckled mode, when subjected to transverse loads, displaying negative stiffness, and dissipating a significant portion of the input energy. This paper presents finite element models (FEMs) developed to investigate the performance of negative stiffness pre-buckled beams and honeycombs. The FEMs were validated using experimental results of single pre-buckled beams and honeycomb structures. The experimental testing of the pre-buckled beams was …


Synergistic Effect Of Macro Synthetic Fiber And Shrinkage-Reducing Admixture On Engineering Properties Of Fiber-Reinforced Super-Workable Concrete, Jingjie Wei, Nima Farzadnia, Kamal H. Khayat Feb 2024

Synergistic Effect Of Macro Synthetic Fiber And Shrinkage-Reducing Admixture On Engineering Properties Of Fiber-Reinforced Super-Workable Concrete, Jingjie Wei, Nima Farzadnia, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study aims to enhance fiber-reinforced super-workable concrete (FR-SWC) by optimizing the system of shrinkage-reducing admixture (SRA) and macro-synthetic fiber (MSF) for low shrinkage and uncompromised mechanical properties. A factorial design approach was employed to model the effect of fiber content, SRA dosage, and combined ratios of two types of MSF on performance of FR-SWC. MSF content had the greatest impact on mechanical properties, followed by SRA and MSF combination. Using MSF increased equivalent flexural strength ratio by 310% compared to the control mixture, regardless of MSF combination and SRA. SRA had the most significant effect on drying shrinkage, followed …


From Pumping To Deposition: A Comprehensive Review Of Test Methods For Characterizing Concrete Printability, Ali Fasihi, Nicolas A. (Ali) Libre Feb 2024

From Pumping To Deposition: A Comprehensive Review Of Test Methods For Characterizing Concrete Printability, Ali Fasihi, Nicolas A. (Ali) Libre

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

3D concrete printing (3DCP) technology has gained significant attention in the construction industry due to its potential to revolutionize the way buildings are designed and constructed. However, successful application of 3DCP requires robust standard test procedures to characterize the printability of concrete. Printability is a measure of workability for a printing material in the 3DCP process, which is characterized by pumpability, extrudability, and buildability. This paper presents a comprehensive review of the test methods that could be used for material characterization during various printing steps, including pumping, extrusion, and layer deposition. The underlying mechanisms relevant to each step, key governing …


Use Of Hybrid Fibers And Shrinkage Mitigating Materials In Scc For Repair Applications, Kamran Aghaee, Kamal H. Khayat Jan 2024

Use Of Hybrid Fibers And Shrinkage Mitigating Materials In Scc For Repair Applications, Kamran Aghaee, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-consolidating concrete (SCC) is used to repair structural elements with congested reinforcement or restricted access to placement and consolidation. In addition to adequate flowability, passing ability, filling capacity, and stability, adequate bonding to the substrate and reinforcing bars, low shrinkage and cracking resistance are required for successful repair. This study employs various shrinkage mitigating materials, including expansive agent (EA), coupled use of EA with shrinkage reducing admixture (SRA), and EA with pre-saturated lightweight sand (LWS) to fulfill these requirements. The effect of these materials on the performance of SCC made with a hybrid synthetic (PP) fiber and a hybrid steel-synthetic …


The Hydration, Microstructure, And Mechanical Properties Of Vaterite Calcined Clay Cement (Vc³), Yaqiang Li, Yue Li, Hongyan Ma, Jiaqi Li Jan 2024

The Hydration, Microstructure, And Mechanical Properties Of Vaterite Calcined Clay Cement (Vc³), Yaqiang Li, Yue Li, Hongyan Ma, Jiaqi Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Limestone (calcite) calcined clay cement (LC3) is a promising low-CO2 binder, but the low activity of calcite cannot compensate the reduction in clinker factor, resulting in low one-day strength and limiting its broad applications. As recent carbon capture and utilization technologies allow scalable production of vaterite, a more reactive CaCO3 polymorph, we overcome the challenge by introducing vaterite calcined clay cement (VC3), inspired by the vaterite-calcite phase change. In the present study, VC3 exhibits higher compressive strengths and faster hydration than LC3. Compared to hydrated LC3, hydrated VC3 exhibits increased amount of hemi- and mono-carboaluminate formation and decreased amount of …


Quantifying The Role Of Insurance In Tornado-Impacted Community Recovery: A Survey And Simulation-Based Approach, Jie Zhao, Ji Yun Lee, Guirong Grace Yan, Fangjiao Ma Jan 2024

Quantifying The Role Of Insurance In Tornado-Impacted Community Recovery: A Survey And Simulation-Based Approach, Jie Zhao, Ji Yun Lee, Guirong Grace Yan, Fangjiao Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Insurance against disasters plays a critical role in community recovery by providing policyholders with reliable and timely payments for repairing or reconstructing damaged houses. By allowing homeowners to transfer risk, insurance enables homeowners to address house without experiencing significant financial burdens. Although historical events have highlighted the importance of insurance, its quantitative impact on community recovery, particularly in tornado-impacted communities, is understudied. This study focuses on advancing our understanding of whether sufficiently insured houses can have a positive impact on the recovery of tornado-impacted communities (i.e., the main research question). This paper proposes a two-stage simulation framework to quantitatively evaluate …


Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability, Amine El Mahdi Safhi, Hamed Dabiri, Ahmed Soliman, Kamal Khayat Dec 2023

Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability, Amine El Mahdi Safhi, Hamed Dabiri, Ahmed Soliman, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Interest in Implementing Self-Consolidating Concrete (SCC) in Major Construction Projects Has Increased Significantly in Recent Years. This Paper Reports the Results of an Extensive Survey of Experimental Data of More Than 1700 SCC Mixtures from over 100 Studies Published in the Last Decade. the Survey Included the SCC Mixture Proportioning, Key Fresh Properties Including Flowability, Passing Ability, and Segregation Resistance, as Well as Some of the Derived Properties (E.g., Paste Volume). the Statistical Analysis of the Reported Parameters Showed Wide Variations in Values. the Outcome of the Survey Indicates that SCC Mixture Design and Workability Properties Do Not Systematically …


Design And Performance Of Fiber-Reinforced Shrinkage Compensating Eco-Friendly Concrete, Kamran Aghaee, Kamal Khayat Dec 2023

Design And Performance Of Fiber-Reinforced Shrinkage Compensating Eco-Friendly Concrete, Kamran Aghaee, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Eco-Crete is an ecological and economical concrete that benefits from high packing density of solid materials and reduced paste. Eco-Crete can enhance the service life of structures by reducing the risk of shrinkage cracking. In this study, shrinkage mitigating materials included an expansive agent (EA), a shrinkage reducing admixture (SRA), and a lightweight sand (LWS), as well as steel and synthetic fibers were used to minimize the risk of cracking. A total of 35 fiber-reinforced Eco-Crete mixtures were prepared with 350 kg/m3 of cementitious materials and 55 % substitution of fly ash and slag. Key fresh and mechanical properties in …


Barriers To Use Of Cross-Laminated Timber In Maine, Shane R. O'Neill Dec 2023

Barriers To Use Of Cross-Laminated Timber In Maine, Shane R. O'Neill

Forest Resources Faculty Scholarship

To increase understanding of both the adoption rate and in-state manufacturing of mass timber In Maine, the 131st Legislature and Governor Mills passed LD 881, a resolve directing a study of the barriers facing cross-laminated timber In Maine and provide recommendations to promote their use in construction. This study was developed in response to the resolve. The study engaged 108 unique participants to define available training, education, and experiences across the stakeholders throughout the building lifecycle process in the state.

From this information, the following five recommendations are proposed:

  1. Understand the policies and initiatives of other states to develop …


Truck Platooning Reshapes Greenhouse Gas Emissions Of The Integrated Vehicle-Road Infrastructure System, Huailei Cheng, Yuhong Wang, Dan Chong, Chao Xia, Lijun Sun, Jenny Liu, Kun Gao, Ruikang Yang, Tian Jin Dec 2023

Truck Platooning Reshapes Greenhouse Gas Emissions Of The Integrated Vehicle-Road Infrastructure System, Huailei Cheng, Yuhong Wang, Dan Chong, Chao Xia, Lijun Sun, Jenny Liu, Kun Gao, Ruikang Yang, Tian Jin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Reducing greenhouse gas emissions has turned into a pillar of climate change mitigation. Truck platooning is proposed as a strategy to lower emissions from vehicles on roads. However, the potential interactive impacts of this technology on road infrastructure emissions remain unclear. Here, we evaluate the decarbonization effects of truck platooning on the integrated vehicle-road system at a large-scale road network level, spanning 1457 road sections across North America. We show that truck platooning decreases emissions induced by truck operations, but it degrades faster the durability of road infrastructure and leads to a 27.9% rise in road emissions due to more …


Effectiveness Of The Different Eutectic Phase-Change Materials In Cooling Asphalt Pavement, Jiasheng Dai, Feng Ma, Zhen Fu, Jenny Liu, Chen Li, Yingjie Hou, Hanli Wu Dec 2023

Effectiveness Of The Different Eutectic Phase-Change Materials In Cooling Asphalt Pavement, Jiasheng Dai, Feng Ma, Zhen Fu, Jenny Liu, Chen Li, Yingjie Hou, Hanli Wu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Choosing a Phase-Change Material (PCM) Adapted to the Specific Phase-Change Temperature (Tm) Required for Each Temperature Condition is of Utmost Importance in Cooling Pavements. Eutectic Phase-Change Materials (EPCMs) Realize the Customization of the Desired Tm and Reduce the Difficulty of Matching PCMs. This Work Aims to Investigate the Effectiveness of a Group of Binary/ternary EPCMs with Tm Ranging from 30 to 60 ℃ and Melting Enthalpies of Around 200 J/g as Thermal Regulation Components for Different Asphalt. to Achieve This Goal, the Thermal and Rheological Properties of Phase-Change Asphalt Binders (PCAB) Were Evaluated by Differential Scanning Calorimeter, Thermogravimetric, Fourier Transform …


International Information Management And Bim Best Practice Report, Ted Mckenna, Davitt Lamon Nov 2023

International Information Management And Bim Best Practice Report, Ted Mckenna, Davitt Lamon

Reports

In order to inform the Digital Leadership and Cultural Change pillar of the Build Digital, a study of international best practice in digital adoption within the built environment sector globally was undertaken and is presented here-in. In order to identify key learnings for Ireland in the context of digital transformation, eight countries were included in this study, namely, Denmark, Finland, Netherlands, Germany, United Kingdom (UK), New Zealand, Australia and Singapore. These countries were selected for various reasons, including the level of digital maturity, the scale of the built environment sector and geographic spread. Key data for each country is included …


Sustainability And Circular Economy Horizon Scan And Needs Analysis, Sadaf Dalirazar, Mark Kelly, Derek Sinnott, James O'Donnell Nov 2023

Sustainability And Circular Economy Horizon Scan And Needs Analysis, Sadaf Dalirazar, Mark Kelly, Derek Sinnott, James O'Donnell

Reports

The construction industry plays a crucial role in addressing the climate crisis as it is the largest global consumer of raw materials and contributes significantly to global energy consumption and emissions. Considering the world’s continuous population growth and the imperative to address infrastructure and housing demands the construction sector needs to adopt further sustainable strategies in its activities to reduce the pressure on natural resources. In addition, the Architecture, Engineering, and Construction (AEC) sector is responsible for generating substantial amount of waste known as Construction and Demolition Waste (CDW), which is projected to increase due to the future construction developments. …


Digital Construction Annual Survey 2022 Report, Davitt Lamon, Ted Mckenna Nov 2023

Digital Construction Annual Survey 2022 Report, Davitt Lamon, Ted Mckenna

Reports

The Annual Survey 2022 was conducted to assess the state of digital transformation in the Irish construction and built environment sector. This report presents the analysis of survey data, with a focus on implications for the Build Digital project and Build Digital’s five pillars: Digital Leadership & Cultural Change, Digital Standards, Digital Education & Training, Digital Procurement, and Sustainability & Circular Economy. Key findings from the survey indicated that a significant number of organisations have started their digital transformation journey, with many identifying themselves as proactive and possessing a clear business-focused strategy. However, a considerable cohort of respondents are keen …


Cement-Based Materials With Solid-Gel Phase Change Materials For Improving Energy Efficiency Of Building Envelope, Zhuo Liu, Jiang Du, Ryan Steere, Joshua P. Schlegel, Kamal Khayat, Weina Meng Nov 2023

Cement-Based Materials With Solid-Gel Phase Change Materials For Improving Energy Efficiency Of Building Envelope, Zhuo Liu, Jiang Du, Ryan Steere, Joshua P. Schlegel, Kamal Khayat, Weina Meng

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

This paper evaluated the cement-based materials incorporated with novel solid-gel phase change materials (PCMs) for improving the energy efficiency of building envelopes. This novel PCM is form-stable, which will not leak as solid-liquid PCMs do and not need encapsulation, and it features high energy-storage capacity. Experimental results showed that the thermal properties of cement-based materials were improved as the increase of PCM content. A 30% replacement of sand by volume with PCM can increase the latent heat of the mixture from around 0 to 7 J/g and decrease the thermal conductivity of PCM mortar based on the generalized self-consistent (GSC) …


Effect Of Type And Quantity Of Inherent Alkali Cations On Alkali-Silica Reaction, Pengfei Ma, Jiaoli Li, Jincheng Bai, Ying Zhuo, Lingyu Chi, Yanping Zhu, Zhenhua Shi, Hongyan Ma, Genda Chen Nov 2023

Effect Of Type And Quantity Of Inherent Alkali Cations On Alkali-Silica Reaction, Pengfei Ma, Jiaoli Li, Jincheng Bai, Ying Zhuo, Lingyu Chi, Yanping Zhu, Zhenhua Shi, Hongyan Ma, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, the macroscopical expansion induced by alkali-silica reaction (ASR) and its corresponding ASR products are investigated using ordinary Portland cement (OPC) mortar specimens with a gradient of boosted alkalis. Experimental results show that the expansion increases with the concentration of inherent alkalis. Sodium-boosted samples expand approximately three times as much as potassium-boosted samples. ASR gels that are present in aggregate veins are calcium-free and amorphous; the atomic ratios of ASR gels are nearly independent of the type and quantity of alkali cations. Aggregate ASR gel exudation occurs in high (≥2.5 %) sodium cases and produces potential Na-shlykovite. Crystalline …


Evaluation Of Residual Flexural Behavior Of Corroded Fiber-Reinforced Super Workable Concrete Beams, Jingjie Wei, Nima Farzadnia, Alfred Addai-Nimoh, Kamal Khayat Nov 2023

Evaluation Of Residual Flexural Behavior Of Corroded Fiber-Reinforced Super Workable Concrete Beams, Jingjie Wei, Nima Farzadnia, Alfred Addai-Nimoh, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Study Investigates the Effect of Macro Synthetic Fiber (MSF) Volume and Crack Widths on Corrosion of the Reinforcing Bars and Residual Flexural Behavior of Fiber-Reinforced Super-Workable Concrete (FR-SWC) Beams Exposed to Accelerated Corrosion. FR-SWC Beams Prepared with 0, 0.33%, and 0.66% MSF Were Pre-Cracked at 0.2-, 0.4-, and 0.75-Mm Widths Before Corrosion Testing. the Controlled Crack Width Was Initiated in One Set of Beams that Were Then Unloaded. the Crack Width Was Maintained for Another Set of Beams during Corrosion Testing by Inserting a Shim. Test Results Showed that the Use of 0.33% and 0.66% MSF Reduced Crack Development …


Transportation Components Of The City Of Bennet Comprehensive Plan And Downtown Economic Development Plan, Kyle Mclaughlin Nov 2023

Transportation Components Of The City Of Bennet Comprehensive Plan And Downtown Economic Development Plan, Kyle Mclaughlin

Community and Regional Planning Program: Theses and Student Projects

In partnership with the City of Bennet, the University of Nebraska, and Marvin Planning Consultants, this project assisted the creation of the City’s Comprehensive Plan and Downtown Economic Development Plan by creating a transportation focused report as a supplement to those plans. The project operates in six sections; Introduction and Overview, Evaluate the Present, Engage the Community, Recommendations, Strategies, and Policies, Implementation and Funding, and Monitoring and Evaluation. The project scope included existing conditions understanding, qualitative and quantitative transportation analysis, public engagement and stakeholder meetings, coordination with two plan creators, identifying transportation improvements, description of implementation steps, overview of available …


Evaluation Of Feasibility And Performance Of Foamed Fire-Resistant Coating Materials, Anyou Zhu, Hanli Wu, Yizhuang David Wang, Jenny Liu Oct 2023

Evaluation Of Feasibility And Performance Of Foamed Fire-Resistant Coating Materials, Anyou Zhu, Hanli Wu, Yizhuang David Wang, Jenny Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A preliminary study found high-performance cement mortar, geopolymer mortar, and magnesium phosphate cement mortar (MPCM) have the potential as new fire-resistant materials. In this study, foam was added to these three fire-resistant materials to further improve their rheological, mechanical, and fire-resistant performance and reduce costs. Systematic design and experimental programs were conducted. The results showed the addition of foam enhanced workability, adhesiveness, and fire resistance, allowing the materials to withstand higher temperatures and further delay heat transfer. A mixture of 70% MPCM and 30% foam was identified as the optimum design, which could withstand 1000 °C with low heat transfer …


Improving Rheological And Thermal Performance Of Gilsonite-Modified Binder With Phase Change Materials, Farshad Saberi K., Yizhuang David Wang, Jenny Liu Oct 2023

Improving Rheological And Thermal Performance Of Gilsonite-Modified Binder With Phase Change Materials, Farshad Saberi K., Yizhuang David Wang, Jenny Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Gilsonite, as a type of natural asphalt binder, has been used to improve the high-temperature performance of regular asphalt binders. However, the addition of Gilsonite may compromise binders' low-temperature thermal cracking resistance. In this research, polyethylene glycol (PEG), as one type of the phase change materials (PCMs), was used as an innovative material to balance the impacts of Gilsonite on high and low performance of asphalt binders. The dosages of Gilsonite and PEG were first determined based on the materials' rheological behaviors at low temperatures. The performance of the PEG-Gilsonite-modified binder was then fully evaluated in terms of the resistance …


Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat Oct 2023

Mechanism Underlying Effect Of Expansive Agent And Shrinkage Reducing Admixture On Mechanical Properties And Fiber-Matrix Bonding Of Fiber-Reinforced Mortar, Kamran Aghaee, Taihao Han, Aditya Kumar, Kamal Khayat

Materials Science and Engineering Faculty Research & Creative Works

Expansive agent (EA) and shrinkage reducing admixture (SRA) are utilized to reduce shrinkage and risk of cracking in concrete. EA compensates shrinkage by initial expansion, and SRA reduces surface tension in the pore fluid. Although EA and SRA effectively reduce shrinkage, they can impair micro-structure of concrete at high contents. The shrinkage reduction effect of EA and SRA is well known; however, there is limited knowledge about their negative effect on microstructure and fiber matrix interfacial transition zone (ITZ). The current study explores the effect of using 10 % CaO-based EA, 2 % SRA, and their combination on mechanical, shrinkage, …


Rilem Tc 266-Mrp: Round-Robin Rheological Tests On High Performance Mortar And Concrete With Adapted Rheology—Evaluating Structural Build-Up At Rest Of Mortar And Concrete, Sofiane Amziane, Kamal Khayat, Mohammed Sonebi, Arnaud Perrot Oct 2023

Rilem Tc 266-Mrp: Round-Robin Rheological Tests On High Performance Mortar And Concrete With Adapted Rheology—Evaluating Structural Build-Up At Rest Of Mortar And Concrete, Sofiane Amziane, Kamal Khayat, Mohammed Sonebi, Arnaud Perrot

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Presents the Results of a Round-Robin Testing Program Undertaken by RILEM TC-266-Measuring Rheological Properties of Cement-Based Materials in May 2018 at the Université D'Artois in Bethune, France. Seven Types of Rheometers Were Compared; They Consisted of Four ICAR Rheometers, Viskomat XL Rheometer, EBT-V Rheometer, Sliding Pipe Rheometer (SLIPER), RheoCAD Rheometer, and 4SCC Rheometer, as Well as the Plate Test. This Paper Discusses the Results of the Evolution of the Static Yield Stress at Rest of Three Mortar and Five Concrete Mixtures that Were Determined using Two ICAR Rheometers, Viskomat XL, and EBT-V Rheometers, as Well as the Plate …