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Full-Text Articles in Engineering

Common Ground Newsletter Fall 2024, Missouri University Of Science And Technology Sep 2024

Common Ground Newsletter Fall 2024, Missouri University Of Science And Technology

Common Ground

-Internship Experiences

-Lady Softball Trio

-Summer Camps

-Design Teams


Reduction In Scc Form Pressure Through In-Situ Co2 Mineralization, Sean Monkman, Soo Duck Hwang, Kamal Khayat Sep 2024

Reduction In Scc Form Pressure Through In-Situ Co2 Mineralization, Sean Monkman, Soo Duck Hwang, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

One challenge of using self-consolidating concrete (SCC) for cast-in-place structural applications is that the rheological properties of the concrete (low yield stress and low plastic viscosity) can lead to increased lateral pressure exerted on the formwork. High structural build up and thixotropy can reduce the lateral pressure, thereby allowing for simpler formwork and faster construction. The addition of CO2 to SCC, in proportions from 0.063 % to 0.250 %, by weight of cement, was investigated as a rheology modifier. The CO2 served to increase the plastic viscosity with little impact on the dynamic yield stress up to a …


Transfer Learning With Spinally Shared Layers, H. M.Dipu Kabir, Subrota Kumar Mondal, Syed Bahauddin Alam, U. Rajendra Acharya Sep 2024

Transfer Learning With Spinally Shared Layers, H. M.Dipu Kabir, Subrota Kumar Mondal, Syed Bahauddin Alam, U. Rajendra Acharya

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Transfer-learned models have achieved promising performance in numerous fields. However, high-performing transfer-learned models contain a large number of parameters. In this paper, we propose a transfer learning approach with parameter reduction and potential high performance. Although the high performance depends on the nature of the dataset, we ensure the parameter reduction. In the proposed SpinalNet shared parameters, all intermediate-split-incoming parameters except the first-intermediate-split contain a shared value. Therefore, the SpinalNet shared parameters network contains three parameter groups: (1) first input-split to intermediate-split parameters, (2) shared intermediate-split-incoming parameters, and (3) intermediate-split-to-output-split parameters. The total number of parameters becomes lower than the …


Price Escalation In Construction Projects: Examining National And International Contracts, Bahaa Chammout, Islam H. El-Adaway, Mohammad Abdul Nabi, Rayan H. Assaad Sep 2024

Price Escalation In Construction Projects: Examining National And International Contracts, Bahaa Chammout, Islam H. El-Adaway, Mohammad Abdul Nabi, Rayan H. Assaad

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The construction industry has witnessed unprecedented disruptions in the supply chain (SC) over the past four years due to the consecutive impacts of the 2018 steel and aluminum tariffs, the COVID-19 pandemic, and the Russian-Ukrainian war. SC disruptions have been linked to price escalations, the management of which varies across different construction contracts. Thus, there is a timely need to understand the contractual implications of price escalation clauses. This article fulfills this research requirement by following an interdependent research methodology. First, the authors analyzed and compared price escalation provisions under various US-based, international, and UK-based standard design-bid-build contracts. Second, the …


Environmental Engineering 3.0: Faced With Planetary Problems, Solutions Must Scale-Up Caring, Daniel B. Oerther, Sarah Oerther, Linda A. Mccauley Sep 2024

Environmental Engineering 3.0: Faced With Planetary Problems, Solutions Must Scale-Up Caring, Daniel B. Oerther, Sarah Oerther, Linda A. Mccauley

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.


Genetically Linked Litho- And Organo-Facies In Meter-Scale Cycles Of Lacustrine Deposits Within The Permian Lucaogou Formation In The Bogda Mountains, Northwest China: Implications For Paleoenvironment And Organic Matter Origin, Xin Zhan, Wan Yang, Qiao Feng, Zhao Wen Zhan, Sile Wei, Yujiao Zhang, Hongquan Kang, Tao Cheng, Hongyan Zhao, Wenjie Cai Sep 2024

Genetically Linked Litho- And Organo-Facies In Meter-Scale Cycles Of Lacustrine Deposits Within The Permian Lucaogou Formation In The Bogda Mountains, Northwest China: Implications For Paleoenvironment And Organic Matter Origin, Xin Zhan, Wan Yang, Qiao Feng, Zhao Wen Zhan, Sile Wei, Yujiao Zhang, Hongquan Kang, Tao Cheng, Hongyan Zhao, Wenjie Cai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A close correlation between lithofacies and organofacies in meter-scale high-order cycles composed of lacustrine sediments enables comparison and refinement of lithofacies-defined cyclostratigraphy. Four lithofacies and four organofacies have been identified in fluctuating profundal high-order cycles in the lower-Permian Lucaogou Formation, southern Bogda Mountains, NW China. The four lithofacies include interbedded and interlaminated coarse siltstone and very fine sandstone, black shale, wackestone and dolostone, and calcareous and dolomitic shales. Four distinctive organofacies have been identified, on the basis of geochemical composition of organic matter and specific biomarker proxies related to organic matter types, rather than to depositional conditions and thermal maturity. …


256-Level Honey Memristor-Based In-Memory Neuromorphic System, Harshvardhan Uppaluru, Zoe Templin, Mohammed Rafeeq Khan, Md Omar Faruque, Feng Zhao, Jinhui Wang Sep 2024

256-Level Honey Memristor-Based In-Memory Neuromorphic System, Harshvardhan Uppaluru, Zoe Templin, Mohammed Rafeeq Khan, Md Omar Faruque, Feng Zhao, Jinhui Wang

Electrical and Computer Engineering Faculty Research & Creative Works

Promising synaptic behavior has been exhibited by memristors based on natural organic materials. Such memristor-based neuromorphic systems offer notable benefits, including environmental sustainability, low production and disposal costs, non-volatile storage capability, and bio/Complementary Metal-Oxide-Semiconductor (CMOS) compatibility. Here, a 256-level honey memristor-based neuromorphic system is experimentally evaluated for image recognition. In detail, first, 256-level honey memristors are manufactured and tested based on in-house technology; next, the non-linear characteristics and inherent variation of honey memristor devices, which lead to imprecise weight updates and limit the inference accuracy, are investigated. Experimental results indicate that the inference accuracy of the 256-level honey memristor-based neuromorphic …


A New Air-Assisted Flare Tip Design For Managing Gas Flare Emissions (Cfd Analysis), Ahmed A. Maaroof, Joseph D. Smith, Mohammed H.S. Zangana Sep 2024

A New Air-Assisted Flare Tip Design For Managing Gas Flare Emissions (Cfd Analysis), Ahmed A. Maaroof, Joseph D. Smith, Mohammed H.S. Zangana

Chemical and Biochemical Engineering Faculty Research & Creative Works

Recently, flares have been considered as a major source of air pollution from the petroleum refining industry. The United Nations has instigated an international effort related to the management of flare emissions to reduce the global warming impact related to flaring. Eliminating or removing the need for gas flares is difficult because these devices are generally used as safety devices to allow the combustion of flammable gases in a controlled fashion which supports safe operation. However, reducing flaring is generally possible using well-designed, efficiently operated flare equipment. In general, flare performance can be enhanced following the API-521 methodology and using …


Quantitative Assessment Of The Architect's Role Under Us Standard Construction Contracts: A Graph Theory Approach, Mariam Elazhary, Ahmed Shiha, Islam H. El-Adaway, Sammi Young Sep 2024

Quantitative Assessment Of The Architect's Role Under Us Standard Construction Contracts: A Graph Theory Approach, Mariam Elazhary, Ahmed Shiha, Islam H. El-Adaway, Sammi Young

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Evaluating the Architect's Role in Construction Contracts is Vital for Improving the Contractual Relationship and Preventing Disputes. Standard Contracts Define the Architect as an Owner's Agent And/or a Contract Administrator. Studies Often Use Qualitative and Subjective Evaluations to Analyze the Architect's Role. However, there is a Lack of Quantitative Measures that Objectively Evaluate the Architect's Capacities in Construction Contracts. This Paper Fills This Knowledge Gap. This Study Proposes a Quantitative Graph Theory-Based Approach to Analyze the Architect's Roles under Three Standard Forms of Construction Contracts in the US: (1) Extracting and Classifying Party Interactions; (2) Modeling the Interactions using Network …


A Robust Recurrent Neural Networks-Based Surrogate Model For Thermal History And Melt Pool Characteristics In Directed Energy Deposition, Sung Heng Wu, Usman Tariq, Ranjit Joy, Muhammad Arif Mahmood, Asad Waqar Malik, Frank Liou Sep 2024

A Robust Recurrent Neural Networks-Based Surrogate Model For Thermal History And Melt Pool Characteristics In Directed Energy Deposition, Sung Heng Wu, Usman Tariq, Ranjit Joy, Muhammad Arif Mahmood, Asad Waqar Malik, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In directed energy deposition (DED), accurately controlling and predicting melt pool characteristics is essential for ensuring desired material qualities and geometric accuracies. This paper introduces a robust surrogate model based on recurrent neural network (RNN) architectures—Long Short-Term Memory (LSTM), Bidirectional LSTM (Bi-LSTM), and Gated Recurrent Unit (GRU). Leveraging a time series dataset from multi-physics simulations and a three-factor, three-level experimental design, the model accurately predicts melt pool peak temperatures, lengths, widths, and depths under varying conditions. RNN algorithms, particularly Bi-LSTM, demonstrate high predictive accuracy, with an R-square of 0.983 for melt pool peak temperatures. For melt pool geometry, the GRU-based …


Ground Vacuum Facility To Simulate Low Earth Orbit Plasma Environment, Emmanuel Kofi Asuako Wie-Addo, Jacob Ortega, Daoru Han Sep 2024

Ground Vacuum Facility To Simulate Low Earth Orbit Plasma Environment, Emmanuel Kofi Asuako Wie-Addo, Jacob Ortega, Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a large vacuum facility (6-ft-diameter, 10-ft-long chamber) equipped with a magnetic filter-type low Earth orbit plasma source. A recommended operating envelope for the plasma source was established through single-point measurements by varying the discharge currents of the plasma source and the gas flow rates. A three-axis translation stage was fabricated and tested with 2D and 3D scans of the simulated plasma environment. The measured plasma density during this study was between 1:63 x 1012 − 3:1 x 1012 m−3 for the electrons and 7:54 x 1012 − 1:82 x 1013 m−3 for the ions, whereas the electron …


The Role Of The Metaverse In Transforming The Management Skill Set Of Construction Practitioners, Ali M. Saad, Islam H. El-Adaway Sep 2024

The Role Of The Metaverse In Transforming The Management Skill Set Of Construction Practitioners, Ali M. Saad, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.


Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk Sep 2024

Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. The aging of asphalt binder during construction is traditionally modeled by rolling thin film oven (RTFO) testing, while aging during service life is modeled by pressure aging vessel (PAV) testing. Comparing these models to the aging of binders in actual pavements is limited because, to be used for current testing, binders must be separated from the pavement's aggregate by solvent extraction. Solvent extraction will, at …


Nuclear Magnetic Resonance (Nmr) Assessment Of Bio And Crude Oil-Based Rejuvenation, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk Sep 2024

Nuclear Magnetic Resonance (Nmr) Assessment Of Bio And Crude Oil-Based Rejuvenation, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Asphalt binders in pavements lose their stability through aging and eventually fail in the field. Using nuclear magnetic resonance (NMR) to monitor the primary longitudinal relaxation time of asphalt samples and the ratio of material that carries this primary relaxation time has been shown to indicate the impact of ultraviolet (UV) radiation on the aging of asphalt pavements. Longitudinal NMR relaxation was used to investigate two types of proposed asphalt rejuvenators, a bio-oil-based rejuvenator and a crude-oil-based rejuvenator. Two different binders with the performance grades (PG) 64-22 and 76-22 were considered for their interactions with the rejuvenators. After 72 h …


Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk Sep 2024

Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. the aging of asphalt binder during construction is traditionally modeled by rolling thin film oven (RTFO) testing, while aging during service life is modeled by pressure aging vessel (PAV) testing. Comparing these models to the aging of binders in actual pavements is limited because, to be used for current testing, binders must be separated from the pavement's aggregate by solvent extraction. Solvent extraction will, at …


Surrogate-Based Multidisciplinary Optimization For The Takeoff Trajectory Design Of Electric Drones, Samuel Sisk, Xiaosong Du Sep 2024

Surrogate-Based Multidisciplinary Optimization For The Takeoff Trajectory Design Of Electric Drones, Samuel Sisk, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft attract attention due to their unique characteristics of reduced noise, moderate pollutant emission, and lowered operating cost. However, the benefits of electric vehicles, including eVTOL aircraft, are critically challenged by the energy density of batteries, which prohibit long-distance tasks and broader applications. Since the takeoff process of eVTOL aircraft demands excessive energy and couples multiple subsystems (such as aerodynamics and propulsion), multidisciplinary analysis and optimization (MDAO) become essential. Conventional MDAO, however, iteratively evaluates high-fidelity simulation models, making the whole process computationally intensive. Surrogates, in lieu of simulation models, empower efficient MDAO with the …


Forecasting Construction Material Prices Using Macroeconomic Indicators Of Trading Partners, Ahmed Shiha, Islam H. El-Adaway Sep 2024

Forecasting Construction Material Prices Using Macroeconomic Indicators Of Trading Partners, Ahmed Shiha, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Supply chain instabilities and inflated material prices have had a disruptive impact on cost estimating of construction projects. While several research efforts used national macroeconomic indicators to forecast the prices of domestically produced construction materials, none of the existing studies investigated whether the lagged macroeconomic indicators of the main trading partners could enhance the predictability of the prices of cement, steel, and lumber in the US construction sector. This paper fills this knowledge gap. The authors adopted a multi-step methodology that included: (1) collecting data on the target variables and the candidate leading indicators; (2) identifying the structural breaks in …


Antibiotic-Loaded Dendrimer Hydrogels In Periodontal Bone Regeneration: An In Vitro Release Feasibility Study, Nicholas Yesbeck, Da Huang, Caroline Carrico, Parthasarathy Madurantakam, Hu Yang Sep 2024

Antibiotic-Loaded Dendrimer Hydrogels In Periodontal Bone Regeneration: An In Vitro Release Feasibility Study, Nicholas Yesbeck, Da Huang, Caroline Carrico, Parthasarathy Madurantakam, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

The prescription of a course of oral antibiotics following bone grafting procedures is a common practice in clinical periodontics to reduce surgical site infections. The goal of this study is to characterize the release profile of antibiotics via local delivery using dendrimer hydrogels (DH) and to analyze the effect of two different particulate bone allografts on the release of the antibiotics in vitro. DH were synthesized from Poly amidoamine (PAMAM) dendrimer G5 and polyethylene glycol diacrylate, and cefazolin was chosen as the antibiotic. The antibiotic-loaded samples were bathed in PBS and incubated at 37 °C; aliquots were taken (1 h, …


Response Of ¹¹B Enriched Zrb2 Ultra-High Temperature Ceramic To Neutron Irradiation At Elevated Temperatures, Yan Ru Lin, Takaaki Koyanagi, David J. Sprouster, Christian M. Petrie, William Fahrenholtz, Greg Hilmas, Yutai Katoh Sep 2024

Response Of ¹¹B Enriched Zrb2 Ultra-High Temperature Ceramic To Neutron Irradiation At Elevated Temperatures, Yan Ru Lin, Takaaki Koyanagi, David J. Sprouster, Christian M. Petrie, William Fahrenholtz, Greg Hilmas, Yutai Katoh

Materials Science and Engineering Faculty Research & Creative Works

ZrB2, an ultra-high temperature ceramic (UHTC) is being considered for use in fusion reactor first-wall structures, yet its response to irradiation remains poorly understood. This study employed scanning/transmission electron microscopy (S/TEM), synchrotron X-ray diffraction (XRD), finite element calculations, and thermal property measurements to thoroughly investigate the neutron-irradiation effects on 11B-enriched ZrB2. Neutron irradiations were conducted at 220 °C and 620 °C, with a neutron fluence of 2.2 x 1025 neutron/m2 (energy > 0.1 MeV), resulting in 3.9 dpa and 4200 appm He. The study revealed the unusual prevalence of prism loops and a > c anisotropic lattice …


Study Of The Structure Of Zn And Na Borophosphate Glasses Using X-Ray And Neutron Scattering Techniques, Uwe Hoppe, Parker T. Freudenberger, Richard K. Brow, Jozef Bednarčik, Alex C. Hannon Sep 2024

Study Of The Structure Of Zn And Na Borophosphate Glasses Using X-Ray And Neutron Scattering Techniques, Uwe Hoppe, Parker T. Freudenberger, Richard K. Brow, Jozef Bednarčik, Alex C. Hannon

Materials Science and Engineering Faculty Research & Creative Works

The atomic structures of Zn and Na borophosphate glasses were studied using X-ray and neutron scattering techniques. Peaks assigned to the B−O, P−O, and O−O distances confirm that only BO4 units co-exist with the PO4 tetrahedra. The Zn−O and Na−O coordination numbers are found to be a little larger than four. The narrowest peaks of the Zn−O first-neighbor distances exist for the glasses along a line connecting the Zn (PO3)2 and BPO4 compositions (50 mol% P2O5), which is explained by networks of ZnO4, BO4, and PO …


Consistent Intraocular Pressure Reduction By Solid Drug Nanoparticles In Fixed Combinations For Glaucoma Therapy, Da Huang, Pedro Norat, Lin Qi, Anna Chernatynskaya, James D. Cole, Vimalin Jeyalatha Mani, Lei Xu, Xiaorong Liu, Hu Yang Aug 2024

Consistent Intraocular Pressure Reduction By Solid Drug Nanoparticles In Fixed Combinations For Glaucoma Therapy, Da Huang, Pedro Norat, Lin Qi, Anna Chernatynskaya, James D. Cole, Vimalin Jeyalatha Mani, Lei Xu, Xiaorong Liu, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Efficient topical drug delivery remains a significant challenge in glaucoma management. Although nanoparticle formulations offer considerable promise, their complex preparation processes, co-delivery issues, and batch consistency have hindered their potential. A scalable fabrication strategy is developed here for preparing solid drug nanoparticles (SDNs) with enhanced drug delivery efficiency. Utilizing hydrophobic antiglaucoma drugs brimonidine (BM) and betaxolol (BX), uniform fixed combination BM/BX SDNs are fabricated through a continuous process, improving batch-to-batch consistency for combined glaucoma treatment. With trehalose being used as a lyoprotectant, BM/BX SDNs can be stored as dry powder and easily reconstituted in phosphate buffered saline. Importantly, reconstituted BM/BX …


Final Report - Nondestructive Data Driven Motion Planning For Inspection Robots, Hung Manh La Aug 2024

Final Report - Nondestructive Data Driven Motion Planning For Inspection Robots, Hung Manh La

Project AS-5

This report presents the development and implementation of autonomous navigation systems for steel bridge inspection robots, designed to enhance the efficiency and safety of bridge maintenance. The Advanced Robotics and Automation (ARA) lab has developed innovative climbing robots capable of operating in complex environments using a hybrid approach that combines mobile and inch-worm-inspired locomotion modes. A novel control and navigation framework has been proposed, featuring algorithms for surface detection, path planning, and mode switching based on 3D point cloud data. The effectiveness of these systems has been validated through experiments on steel bridge structures, demonstrating the potential for real-world application …


Molecular Dynamics Simulation Insights Into Rejuvenating Aged Asphalt With Waste Soybean Oil And Polymers, Ke Shi, Feng Ma, Zhen Fu, Jenny Liu, Ruimeng Song, Dongdong Yuan, Yujie Tang Aug 2024

Molecular Dynamics Simulation Insights Into Rejuvenating Aged Asphalt With Waste Soybean Oil And Polymers, Ke Shi, Feng Ma, Zhen Fu, Jenny Liu, Ruimeng Song, Dongdong Yuan, Yujie Tang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study utilized molecular dynamics simulations to assess the rejuvenation of aged asphalt (AA) with waste soybean oil (WSO) and functionalized SBS polymers, focusing on: 1) constructing and validating models for virgin asphalt (VA), AA, and composite rejuvenated asphalt with WSO and polymers; 2) analyzing diffusion effects and binding abilities in these rejuvenated models; 3) evaluating interface binding and diffusion behaviors in composite rejuvenated models. The addition of functionalized SBS molecules and WSO improved the diffusion rates of various components within these models. Specifically, functionalized linear-SBS (LSBS) molecules demonstrated superior diffusion performance compared to star-SBS (SSBS) molecules. Incorporating WSO and …


Investigation Of The Cohesive Behavior Of Water-Intervened Rejuvenated Sbs-Modified Bitumen, Ke Shi, Feng Ma, Zhen Fu, Jenny Liu, Ruimeng Song, Dongdong Yuan, Yujie Tang Aug 2024

Investigation Of The Cohesive Behavior Of Water-Intervened Rejuvenated Sbs-Modified Bitumen, Ke Shi, Feng Ma, Zhen Fu, Jenny Liu, Ruimeng Song, Dongdong Yuan, Yujie Tang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

When water interacts with bitumen, the diffusion and cohesion characteristics between the components of bitumen are negatively impacted. Molecular dynamics simulations were employed to construct various bitumen models, including bitumen–bitumen (without water), water-containing single bitumen, water-containing bitumen–bitumen, and bitumen–water–bitumen models. The primary research objectives were as follows: comparing the changes in the densities of bitumen models with and without water, analyzing the interlayer cohesive energies of bitumen models interacting with water, evaluating the hydrogen bonds in water-containing bitumen models, and characterizing the diffusion behaviors of bitumen components. The results indicated that when water interacted with the bitumen, it filled internal …


Effect Of Superabsorbent Polymer On 3d Printing Characteristics As Rheology-Modified Agent, Yu Cun Gu, Kamal H. Khayat Aug 2024

Effect Of Superabsorbent Polymer On 3d Printing Characteristics As Rheology-Modified Agent, Yu Cun Gu, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study aims to investigate the effects of two superabsorbent polymer (SAP) types, S1 and S2 (with continual absorption and rapid desorption, respectively) as rheology-modified agent on 3D printing characteristics. Three base mixtures were selected with different thixotropic behaviors (i.e., mixtures with high re-flocculation (τfloc), high structuration rate (Athix), and both low τfloc and Athix, respectively). The initial mini-slump flow of 190±10 mm was secured by adjusting superplasticizer (SP) or water demand (increasing w/b by either 0.025 or 0.05). An extrudable region was determined within the range of τfloc (200-890 Pa) and Athix (15-60 Pa/min). The use of the S2 …


Coupled Effect Of Fiber Type And Reinforcement Ratio On Flexural Behavior Of Reinforced Beams Cast With Super Workable Concrete, Jingjie Wei, Le Teng, Kamal H. Khayat Aug 2024

Coupled Effect Of Fiber Type And Reinforcement Ratio On Flexural Behavior Of Reinforced Beams Cast With Super Workable Concrete, Jingjie Wei, Le Teng, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigated the effect of 5-dimensional hooked-end fiber (5D) on the structural performance of beams and compared its efficiency with other fibers in strengthening structural performance of reinforced concrete (RC) beams with an increase in reinforcement ratio (ρ). The potential of using fibers to reduce the longitudinal rebar based on various design criteria was investigated. The fibers included 5D, a combination of 80 % 3-dimensional hooked-end and 20 % short steel fibers (STST), and two combinations of macro synthetic fibers A and B (MSF). Experimental results indicated that, compared to non-fibrous beams, using 5D was the most efficient in …


Simulation Of Calcium Carbonate Nucleation Processes In Confined C-S-H Nanopores With Different Calcium-Silicon Ratios, Jiao Yu, Kerui Wang, Peixuan Yang, Mengmeng Li, Biqin Dong, Zuquan Jin, Shuxian Hong, Hongyan Ma Aug 2024

Simulation Of Calcium Carbonate Nucleation Processes In Confined C-S-H Nanopores With Different Calcium-Silicon Ratios, Jiao Yu, Kerui Wang, Peixuan Yang, Mengmeng Li, Biqin Dong, Zuquan Jin, Shuxian Hong, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Carbonation curing technology plays an important role in carbon cycling and improving the properties of cement-based materials, while the nucleation and growth mechanism of calcium carbonate (CaCO3) is still unclear. Based on molecular dynamics simulation, the formation process and nucleation mechanism of CaCO3 in confined C-S-H nanopores with different calcium-silicon ratios were studied. The results show that the clustering behavior of CaCO3 in C-S-H nanopores filled with saturated CaCO3 solution can be divided into three phases, rapid agglomeration stage, slow cluster stage, and stable cluster stage. The aggregation is mainly dependent on ionic bonding for …


Final Report - Integration Of Aerial Manipulation, Haptics-Based Human-In-The- Loop Control, And Augmented Reality For Bridge Deck Hosing, Paul Oh, Blake Hament, Dongbin Kim Aug 2024

Final Report - Integration Of Aerial Manipulation, Haptics-Based Human-In-The- Loop Control, And Augmented Reality For Bridge Deck Hosing, Paul Oh, Blake Hament, Dongbin Kim

Project AS-9

This Year 5 and Year 6 report integrates the designs, analyses, and results of the previous years. These have culminated into the design, development and deployment of a hosing-drone. This drone carries and 3000 PSI (pounds per square inch) pressure washer often used to clean bridges. This accomplishment leverages the work in aerial manipulation, human-in-the-loop control, haptics, and augmented- and virtual-reality (AR/VR) executed in prior years. Additionally, this report presents results using a cable-driven parallel robot (CDPR) and telescopic mast. This robot provides another platform that has applications in bridge inspection, maintenance and repair.


Effect Of Absorption Kinetics Of Superabsorbent Polymers On Printability And Interlayer Bond Of 3d Printing Concrete, Yu Cun Gu, Shuyi Zheng, Hongyan Ma, Wu Jian Long, Kamal H. Khayat Aug 2024

Effect Of Absorption Kinetics Of Superabsorbent Polymers On Printability And Interlayer Bond Of 3d Printing Concrete, Yu Cun Gu, Shuyi Zheng, Hongyan Ma, Wu Jian Long, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study examines the effect of the material characteristics of superabsorbent polymers (SAPs) on the printability and interlayer bond strength of 3D printing concrete. Three types of SAP, including two acrylamide-co-acrylic polymers with coarse and fine particle sizes (S1 and S2) and an acrylic copolymer (S3), were employed. The investigated mortar mixtures had a fixed initial mini-slump flow of 195 ± 10 mm and yield stress of 290 ± 25 Pa. The fluidity of SAP-incorporated mortars was maintained by either adjusting the superplasticizer dosage or increasing the water content. Test results indicate that particle flocculation is dependent on SAP absorption …


Extrudability Window And Offline Test Methods To Predict Buildability Of 3d Printing Concrete, Yu Cun Gu, Kamal H. Khayat Aug 2024

Extrudability Window And Offline Test Methods To Predict Buildability Of 3d Printing Concrete, Yu Cun Gu, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Study Investigates the Effect of Thixotropy and Stiffness Evolution on the Extrudability and Buildability of 3D Printing Concrete. Different Types of Supplementary Cementitious Materials and Limestone Filler Were Used to Prepare Mortars with Varying Levels of Thixotropy and Early-Age Stiffness. Mixtures with Yield Stress and Flocculation (Τfloc) of 180–400 and 420–950 Pa, Respectively, Exhibited Adequate Extrudability Without Plastic Collapse. the Printing Was Completed 8–15 Min after Mixing at a Vertical Build-Up Rate of 138 Mm/min. Several Process Parameters, Including Rest Time to Secure a Penetration Resistance of 150 KPa (T150) and Penetration Resistance at Various Rest Times Were Developed …