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Articles 331 - 360 of 2196

Full-Text Articles in Materials Science and Engineering

Influence Of Urease-Induced Calcium Carbonate Precipitation On Frost Heave Characteristics Of Saline Soil, Li Jue, Wen Zili, Liu Zhengnan Feb 2025

Influence Of Urease-Induced Calcium Carbonate Precipitation On Frost Heave Characteristics Of Saline Soil, Li Jue, Wen Zili, Liu Zhengnan

Journal of China & Foreign Highway

This study investigated the impact of the soybean urease-induced calcium carbonate precipitation (SICP ) technique on frost heave characteristics of saline soil,specifically addressing the frost heave in saline soil used as a subgrade.The relationships between compaction degree,moisture content,volume ratio of the reaction liquid,and curing temperature with the frost heave rate of treated soil were explored.The results show that SICP significantly reduces the frost heave rate of soil samples by over 28%,with the most noticeable improvement occurring under conditions of higher compaction degree and lower moisture content.Additionally,the increased volume ratio of reaction liquid enhances reaction efficiency,while lower curing temperatures are crucial …

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Prediction And Evaluation Of Road Service Performance In Cold Regions Based On Uncertainty Quantification Theory, Liu Yuanyuan, Si Junling, Zheng Hao, Ren Daoju, Fan Shaobing, Quan Lei Feb 2025

Prediction And Evaluation Of Road Service Performance In Cold Regions Based On Uncertainty Quantification Theory, Liu Yuanyuan, Si Junling, Zheng Hao, Ren Daoju, Fan Shaobing, Quan Lei

Journal of China & Foreign Highway

In cold regions,road service performance is influenced by various nonlinear dynamic factors under complex hydrothermal environments and freeze-thaw cycles.Traditional empirical and mechanical models exhibit significant limitations in comprehensively considering the impacts of complex environments and conducting quantitative analyses.This study proposed a method to predict and assess the service performance of constructed roads in cold regions.The method integrated deep neural networks with uncertainty quantification theory,addressing the inadequacies of existing models in adapting to complex environments and analyzing multiple influencing factors.By utilizing data from Montana road sections in the LTPP database,the study employed deep neural networks to predict the international roughness index …

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Permanent Deformation Prediction Model Of Subgrade Soil Under Freeze-Thaw Cycles Based On Lstm And Transformer, Zhang Anshun Feb 2025

Permanent Deformation Prediction Model Of Subgrade Soil Under Freeze-Thaw Cycles Based On Lstm And Transformer, Zhang Anshun

Journal of China & Foreign Highway

To accurately predict the permanent deformation of subgrade soil under the coupling effect of freeze-thaw cycles and traffic loads,a hybrid neural network model based on long short-term memory (LSTM ) and Transformer was proposed,building upon the results of dynamic triaxial tests.This model effectively captured the temporal dependencies and complex interactive effects among input variables,thereby significantly enhancing the accuracy and generalization ability of permanent deformation prediction of subgrade soil.The results indicate that higher confining pressure improves the resistance of subgrade soil to deformation,but its permanent deformation behavior is still significantly influenced by the magnitude of cyclic loading and the number of …

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Analysis Of Joint Load Transfer Performanc E Of Prefabricated Steel‑Concrete Hollow Pavement Slab, Zhu Guangshan, Dong Zihao, Yang Ye, Wang Jinshan Feb 2025

Analysis Of Joint Load Transfer Performanc E Of Prefabricated Steel‑Concrete Hollow Pavement Slab, Zhu Guangshan, Dong Zihao, Yang Ye, Wang Jinshan

Journal of China & Foreign Highway

In order to study the joint load transfer capacity of a prefabricated steel-concrete hollow pavement slab,a finite element model was established with ABAQUS to carry out numerical analysis.The variation laws of the maximum deflection value and joint load transfer coefficient of the pavement slab with and without cavitation were compared to analyze the load transfer capacity.The results show that when cavitation occurs in the slab,the load transfer coefficient of the slab decreases with the increase in the cavitation area,but the load transfer coefficient of the slab does not change significantly when the cavitation depth reaches a certain level.When there is …

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A Review Of Performance Of Cement- Stabilized Base Materials Containing Recycled Conc Rete Aggregate, Song Chengzhe, Li Jiaquan, Kong Jingxun, Zhou Changjun, An Xing Feb 2025

A Review Of Performance Of Cement- Stabilized Base Materials Containing Recycled Conc Rete Aggregate, Song Chengzhe, Li Jiaquan, Kong Jingxun, Zhou Changjun, An Xing

Journal of China & Foreign Highway

Semi-rigid base offers excellent performan ce and is widely used as a high-grade highway subgrade in China.Currently,with a large stockpile of waste concrete in the country,using it as aggregate in pavement base materials is of great significance for environmental protection,energy conservation,and emission reduction.In this paper,the basic performance indicators of recycled concrete aggregate (RCA ) and the performance of cement-stabilized base materials containing RCA,including strength,shrinkage,fatigue,and erosion resistance were reviewed.It finds that the basic performance indicators of RCA are lower than those of natural aggregate.Therefore,the proportion of RCA in base materials may be limited to 20% ‒ 50%.The shrinkage and erosion resistance …

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Research Progress Of Modified Asphalt With Graphene Materials, Zhang Zongwei, He Kai Feb 2025

Research Progress Of Modified Asphalt With Graphene Materials, Zhang Zongwei, He Kai

Journal of China & Foreign Highway

To clarify the research status of mo dified asphalt properties with graphene materials,relevant research literature in China and abroad was consulted to compare the effects of various graphene materials and preparation parameters on asphalt.The results show that graphene,nano graphite sheets,and oxidized graphene can improve the microstructure and road performance of asphalt,increase the service life of asphalt,and reduce the maintenance cost of asphalt.Continuously optimizing the preparation parameters of modified asphalt and exploring the mechanism of modified asphalt with new material not only help the promotion and application of new road asphalt technologies but also reduce energy consumption,pollutants,and carbon emissions,providing new ideas …

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Mechanical Performance Of Nuts In Tie Rod Assembly Of Anchorage System Of Suspension Bridge, Liu Zheng, Li Zhao, Qin Guifang, Xie Qinjian, Jiang Yuangen, Zhang Jiyong, Wang Lei, Ma Yafei Feb 2025

Mechanical Performance Of Nuts In Tie Rod Assembly Of Anchorage System Of Suspension Bridge, Liu Zheng, Li Zhao, Qin Guifang, Xie Qinjian, Jiang Yuangen, Zhang Jiyong, Wang Lei, Ma Yafei

Journal of China & Foreign Highway

In order to investigate the stress and fatigue performance of nuts in the tie rod assembly of the anchorage system of a long-span suspension bridge,the finite element software Ansys and Abaqus were used to establish the full bridge model and the local finite element models of the tie rod and the hexagonal nut,respectively.Secondly,the whole process variation law of the synergistic force of the tie rod and the nut under the axial tensile load was revealed.The difference in mechanical performance between slotted nuts and unslotted nuts was compared,and the detailed structural parameters of slotted nuts were optimized.Finally,the static tensile and fatigue …

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Installation Direction Design And Construction Control Of Sliding Bearing Of Continuous Girder Bridge, Guan Changlu, Sun Xiudong, Dong Hao, Wang Xingzhou Feb 2025

Installation Direction Design And Construction Control Of Sliding Bearing Of Continuous Girder Bridge, Guan Changlu, Sun Xiudong, Dong Hao, Wang Xingzhou

Journal of China & Foreign Highway

Continuous girder bridges can improve the structural stress,increase the structural bearing capacity,and promote ride comfort.However,some continuous girder bridges suffer from issues such as bearing dislocation,upper torsion,and damage to seismic arrestors.To identify deficiencies in current design and construction control,an in-depth analysis of these issues was conducted.The findings reveal the main reason is that the bidirectional sliding bearings (nearly half of the total ) fail to provide horizontal force,and the main sliding direction of the unidirectional sliding bearings is inconsistent with the deformation of the bridge superstructure.In this paper,factors including temperature-induced deformation,material shrinkage,elastic compression,creep,and construction process control of the bridge superstructure were …

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Crack Propagation Of Vehicle‑Steel Bridge Deck Slabs Based On Pavement Damage, Tang Sheng, Yin Xinfeng, Zhang Ming, Yan Wanli Feb 2025

Crack Propagation Of Vehicle‑Steel Bridge Deck Slabs Based On Pavement Damage, Tang Sheng, Yin Xinfeng, Zhang Ming, Yan Wanli

Journal of China & Foreign Highway

In order to study the influence of vehicles under different pavement damage conditions on crack propagation of welded toe at the roof of steel bridge deck slabs,finite element models of suspension bridges,fine vehicles,and local steel bridge deck slabs were established,and multiple groups of obstacle heights were set to simulate pavement damage.The explicit dynamic analysis program was used to simulate vehicle-bridge coupling vibration and extract the forces of vehicles on the steel bridge deck slabs at different lanes,speeds,and obstacle heights.The crack propagation life of the welded toe at the roof was obtained by applying them to a local steel bridge deck …

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Calculation Of Socket Depth For Circular Pipe Pier-Bearing Platform Socket Connection, Chen Jingli, Xiao Feng, Wang Zhigang, Wang Zhihai, Xu Yan Feb 2025

Calculation Of Socket Depth For Circular Pipe Pier-Bearing Platform Socket Connection, Chen Jingli, Xiao Feng, Wang Zhigang, Wang Zhihai, Xu Yan

Journal of China & Foreign Highway

The minimum socket depth for circular pipe pier-bearing platform socket connection can be calculated according to Article C.0.3 in the Specifications for Design of Highway Precast Concrete Bridges (JTG/T 3365 -05—2022 ).In order to enable engineering designers to fully understand and correctly apply the calculation formula in this article,this paper first introduced the main technical features of the typical connection scheme,as well as the structural failure principles and objectives formulated in the specification of the typical connection scheme.Then,it briefly introduced the experimental research content and results of the typical connection scheme and explained the key construction measures and their functions …

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Reliability Analysis Of Long‑Span Concrete Box Arch Bridge Under Temperature Effect Combinations, Zheng Junlin, Jiang Youbao, Zheng Xinhao, Lu Naiwei Feb 2025

Reliability Analysis Of Long‑Span Concrete Box Arch Bridge Under Temperature Effect Combinations, Zheng Junlin, Jiang Youbao, Zheng Xinhao, Lu Naiwei

Journal of China & Foreign Highway

The existing design methods for concrete arch bridge structures do not consider the random characteristics of the eccentricity generated by load effects and overlook the influence of stochastic eccentricity on structural reliability.To address this deficiency,a calculation model for eccentricity under temperature effect combinations was derived.The random characteristics of eccentricity for different sections of the main arch of concrete arch bridges and their sectional bearing capacities were analyzed under different load parameter combinations.By utilizing the Monte Carlo method,reliability indices were computed for different sections of the main arch and different load parameter combinations after considering the random characteristics of eccentricity.The results …

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Preparation And Performance Of Emulsified Asphalt With High-Temperature Resistant And Wheel Sticking-Free Effects, Yan Han, Zha Xudong, Kang Xiaogang, Gong Yan, Zhang Zhengji, Zhang Wenshuai Feb 2025

Preparation And Performance Of Emulsified Asphalt With High-Temperature Resistant And Wheel Sticking-Free Effects, Yan Han, Zha Xudong, Kang Xiaogang, Gong Yan, Zhang Zhengji, Zhang Wenshuai

Journal of China & Foreign Highway

To address the problem of wheel sticking at high temperatures in the construction process of existing wheel sticking-free emulsified asphalt of tack coat,this paper adopted the composite modification method of 70# and 15# matrix asphalt and waterborne polyurethane resin (WPR ) to prepare hard asphalt-WPR (HA-WPR )-modified emulsified asphalt in accordance with the high-temperature resistant and wheel sticking-free requirements.Through a series of laboratory tests,the technical performance,wheel sticking-free performance,and interlayer bonding performance of the emulsified asphalt were researched and compared with ordinary wheel sticking-free emulsified asphalt and ordinary emulsified asphalt tack coat oil.The results show that the technical performance of the …

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Model Analysis Of Axial Compressive Mechanical Properties Of Concrete Column Constrained By Textile-Reinforced Engineered Cementitious Composites, Ma Gao, Wang Zhaoyang Feb 2025

Model Analysis Of Axial Compressive Mechanical Properties Of Concrete Column Constrained By Textile-Reinforced Engineered Cementitious Composites, Ma Gao, Wang Zhaoyang

Journal of China & Foreign Highway

In order to avoid the problem of matrix cracking in textile-reinforced concrete (TRC ),a reinforcement method of textile-reinforced engineered cementitious composites (ECC ),namely TRECC composed of textile and high-performance ECC was proposed.However,the research on the axial compressive mechanical properties of TRECC-constrained concrete in China and abroad is still insufficient,and there is a lack of reliable strength and ultimate strain analysis models.A total of 116 axial compression test results of TRC-constrained concrete columns and 125 axial compression test results of TRECC-constrained concrete columns were collected.The confinement mechanisms and failure modes of TRECC and TRC-constrained concrete were compared.Then,the strength models and ultimate …

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Key Techniques For Constructing Flexible Geosynthetic Reinforced Soil Abutments, Yu Xiaoxiao, Xu Chao, Li Haoyu, Zuo Binli Feb 2025

Key Techniques For Constructing Flexible Geosynthetic Reinforced Soil Abutments, Yu Xiaoxiao, Xu Chao, Li Haoyu, Zuo Binli

Journal of China & Foreign Highway

The flexible geosynthetic reinforced soil (GRS ) abutments offer several advantages,including cost saving,reduced bridgehead misalignment,and good seismic performance,showing great potential for application in transportation engineering both in China and abroad.The flexible GRS abutment is essentially composed of a composite structure formed by closely spaced layers of geosynthetic reinforcement material,and the construction quality and load-bearing capacity are crucial to the success of the project.To ensure construction quality and study the construction process of flexible GRS abutments,a construction site monitoring method was adopted.Based on the experience from the construction of a vehicular overpass on the Wuwei ‒ Yuexi Expressway,the quality control measures …

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Research On Mechanical Entry Excavation And Reinforcement Measures For Large Cross-Section Tunnel, Liang Xiao, Li Ke, Guo Hongyan, Hu Xuebing, Yao Chengrui Feb 2025

Research On Mechanical Entry Excavation And Reinforcement Measures For Large Cross-Section Tunnel, Liang Xiao, Li Ke, Guo Hongyan, Hu Xuebing, Yao Chengrui

Journal of China & Foreign Highway

With the innovation of tunnel construction techniques and mechanical equipment,mechanical drilling and blasting for mountain tunnels have gradually developed.However,several challenges exist during the mechanical entry excavation for mountain tunnels,including the significant influence of geological factors,limited equipment adaptability,and constrained working space.This research,based on a specific tunnel project,utilized FLAC3D finite difference software to study the mechanical excavation method and auxiliary reinforcement measures for shallow-buried segments at the large cross-section tunnel portal.A comparative analysis was conducted on the displacement of surrounding rock,the stress of supporting structures,and the variation of plastic zones before and after tunnel face reinforcement for different advances per cycle and …

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Application Research Of Bim Technology In Highway Prefabricated Bridge Scheme Design, Li Jinlong, Wang Xinnan, Liu Dongsheng, Chen Zhongzhi Feb 2025

Application Research Of Bim Technology In Highway Prefabricated Bridge Scheme Design, Li Jinlong, Wang Xinnan, Liu Dongsheng, Chen Zhongzhi

Journal of China & Foreign Highway

At present,the highway bridge scheme requires continuous adjustments and upgrading due to iterative updates of design data and refined investigation of the surrounding environment of the bridge site.This paper upgraded the traditional route design software,developed a GIS-integrated platform,built a three-dimensional environment with design data as the core,and created a bridge scheme model through parametric intelligent design.It also evaluated and optimized the bridge scheme based on the integration of the bridge model and the surrounding environment.The results show that by using BIM technology,the forward design of a bridge scheme based on a three-dimensional environment is realized.This approach automates the scale statistics …

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Simulation-Based Models For Postearthquake Response: A Survey And Research Directions, Abhijit Gosavi, Lauryn A. Spearing, Lesley H. Sneed Feb 2025

Simulation-Based Models For Postearthquake Response: A Survey And Research Directions, Abhijit Gosavi, Lauryn A. Spearing, Lesley H. Sneed

Engineering Management and Systems Engineering Faculty Research & Creative Works

Computer simulation is increasingly being used by emergency planners as a tool to improve disaster response given that it can model real-world scenarios, such as earthquakes. Although there has been an increase in simulation research focused on disaster response, much of this literature is from disparate fields and across disaster scenarios. To bridge this gap, this paper surveys simulation-based models for post-earthquake response from the year 2000 onward. Advantages of simulation over closed-form statistical models are discussed. Three main subproblems in post-earthquake response models are explored: (1) service distribution (e.g., food, water), (2) infrastructure restoration (at the building and transportation …

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Rheology And Early-Age Structure Development In Binary And Ternary Blends Modified With Novel Graphene Types, Sahil Surehali, Collin Gustafson, Sayee Srikarah Volaity, Ranjith Divigalpitiya, Aditya Kumar, Narayanan Neithalath Feb 2025

Rheology And Early-Age Structure Development In Binary And Ternary Blends Modified With Novel Graphene Types, Sahil Surehali, Collin Gustafson, Sayee Srikarah Volaity, Ranjith Divigalpitiya, Aditya Kumar, Narayanan Neithalath

Materials Science and Engineering Faculty Research & Creative Works

Interest in the use of graphene to enhance the properties of cementitious materials is growing, but major impediments in implementation are the cost of graphene and changes in binder rheology attributable to these nanomaterials. This study explores the influence of novel, cost-effective, environment-friendly, and mass-producible graphene on the rheology and early-age structure development of cementitious binders. Two novel graphene types—fractal graphene (FG) and reactive graphene (RG)—are used in plain cement mixtures as well as those containing 30 % (by mass) of fly ash and/or limestone powder, at low dosages of ≤0.02 % by mass of binder. The early- and later-age …

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Thermally Stimulated Stiffening And Fly Ash's Alkaline Activation By Ca(Oh)2 Addition Facilitates 3d-Printing, Xiaodi Dai, Sharu Bhagavathi Kandy, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Edward Garboczi, Torben Gaedt, Samanvaya Srivastava, Gaurav Sant Feb 2025

Thermally Stimulated Stiffening And Fly Ash's Alkaline Activation By Ca(Oh)2 Addition Facilitates 3d-Printing, Xiaodi Dai, Sharu Bhagavathi Kandy, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Edward Garboczi, Torben Gaedt, Samanvaya Srivastava, Gaurav Sant

Materials Science and Engineering Faculty Research & Creative Works

3D-printing could offer substantial benefits to the construction industry including the fabrication of customized/bespoke components, eliminating formwork, and reducing material waste. Despite these advantages, control of the pumpability, extrudability, and buildability of 3D-printed concrete (3DPC) remains challenging. This study demonstrates how the use of fly ash (FA) enables enhanced thermal stiffening, and rapid alkali-activation in the presence of portlandite (Ca(OH)2, CH). In general, blends of CH and FA exhibit less structural build-up at low temperatures, but upon reaching a trigger temperature of 75 °C, these blends achieve rapid stiffening, at rates of ∼800 Pa/s. The rapid stiffening arises from the …

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Effects Of Gypsum And Limestone On Early-Age Hydration And Strength Optimization In Belite Calcium Sulfoaluminate Cement, Sai Akshay Ponduru, Bryan K. Aylas-Paredes, Taihao Han, Advaith Neithalath, Narayanan Neithalath, Gaurav Sant, Aditya Kumar Feb 2025

Effects Of Gypsum And Limestone On Early-Age Hydration And Strength Optimization In Belite Calcium Sulfoaluminate Cement, Sai Akshay Ponduru, Bryan K. Aylas-Paredes, Taihao Han, Advaith Neithalath, Narayanan Neithalath, Gaurav Sant, Aditya Kumar

Materials Science and Engineering Faculty Research & Creative Works

Belite calcium sulfoaluminate cement (CSAB), an alternative to Portland cement, exhibits excellent strength at both early and later ages. However, due to its high belite content, the carbon reduction from this type of cement is not sufficient when compared to other alternative cements. To further enhance CSAB's sustainability, this study investigates the performance of CSAB when partially replaced by low-carbon mineral additives (i.e., limestone and gypsum). The primary objective is to identify the optimal mixture design by incorporating gypsum and limestone to formulate a sustainable binder that maintains high compressive strength. The CSAB is replaced (with both additives) by up …

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Effect Of Shrinkage-Mitigating Materials, Fiber Type, And Repair Thickness On Flexural Behavior Of Beams Repaired With Fiber-Reinforced Self-Consolidating Concrete, Jingjie Wei, Kamal H. Khayat Feb 2025

Effect Of Shrinkage-Mitigating Materials, Fiber Type, And Repair Thickness On Flexural Behavior Of Beams Repaired With Fiber-Reinforced Self-Consolidating Concrete, Jingjie Wei, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

While self-consolidating concrete (SCC) has emerged as a highly effective approach for the repair of concrete structures, there have been few investigations regarding the effect of the combination of different fiber and shrinkage-mitigating material types (shrinkage-reducing admixture, SRA; superabsorbent polymer, SAP; and expansive agent, EA) on the flexural behavior of repaired structures. This study aims to explore the influence of three different shrinkage-mitigating materials (1.25%–2.5 % SRA, 4%–8% EA, and 0.2%–0.4 % SAP), four fiber types (two macro synthetic fibers, MSFA and MSFB; 5D hooked steel fibers, 5D; a combination of 80 % 3D hooked steel +20 % short steel …

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Optimizing And Validation Of Sustainable Uhpc With Waste Glass Powder Utilizing Modified Particle Packing Approach And Response Surface Methodology, Mohamed Taman, Elsaid Maaty, Alaa Mehrez, Ahmed Kamal Isaac Jan 2025

Optimizing And Validation Of Sustainable Uhpc With Waste Glass Powder Utilizing Modified Particle Packing Approach And Response Surface Methodology, Mohamed Taman, Elsaid Maaty, Alaa Mehrez, Ahmed Kamal Isaac

Journal of Engineering Research

The current study explores the potential of utilizing Waste glass powder (WGP) as an alternative to cement in the development of sustainable eco-friendly Ultra-high-performance concrete (UHPC). UHPC mixtures underwent optimization through the application of a Modified Andreasen and Andersen (MAA) particle packing model, resulting in a reduction of cement content from 900 to 800 kg/m3. Six mixes were cast, with varying levels of cement replacement ratios with WGP up to 50%. The evaluation focuses on the flowability, dry density, and mechanical properties of UHPC at different ages using normal curing. A statistical model utilizing response surface methodology (RSM) …

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Integrating Off-Spec Scms Into Plc Blends, George A. Qubty Jan 2025

Integrating Off-Spec Scms Into Plc Blends, George A. Qubty

Civil Engineering Theses - Archive

Off-spec supplementary cementitious materials (SCMs) remain underutilized due to variability in reactivity and non-conformance with existing standards. This study evaluates the hydration behavior and fresh-state and mechanical performance of these materials in Portland limestone cement (PLC) systems. One Class F fly ash (FA), one bottom ash (BA), and two calcined clays (HACC and LACC) were evaluated as 20 % replacements to PLC. Hydration behavior was characterized using isothermal calorimetry and thermogravimetric analysis (TGA), while fresh-state and mechanical performance were assessed through flow table, Vicat setting time, load–crack mouth opening displacement (CMOD) flexural testing, and compressive strength testing. HACC increased compressive …

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Flexural Post-Cracking Performance Of Macro Synthetic Fiber Reinforced Super Workable Concrete Influenced By Shrinkage-Reducing Admixture, Jingjie Wei, Nima Farzadnia, Kamal H. Khayat Jan 2025

Flexural Post-Cracking Performance Of Macro Synthetic Fiber Reinforced Super Workable Concrete Influenced By Shrinkage-Reducing Admixture, Jingjie Wei, Nima Farzadnia, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Most literature has focused on the effect of shrinkage-reducing admixture (SRA) in shrinkage mitigation resistance of concrete. This study aims to examine the impact of SRA on the efficiency of macro synthetic fibers (MSF) in enhancing the flexural post-cracking behavior of fiber-reinforced super workable concrete (FR-SWC). A comparative analysis of the influence of fiber combinations on the flexural post-cracking behavior of beams is also included. Results showed that a higher dosage of SRA, particularly at 5 % by mass of binder, had a noticeable negative impact on flexural post-cracking performance of beams while exhibiting positive effect on workability and shrinkage …

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Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field Jan 2025

Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field

Materials Science and Engineering Faculty Research & Creative Works

Nitrogen pickup during air induction melting can result in porosity and a loss of fracture toughness in ultrahigh-strength quenched and tempered steel castings. Nitrogen atoms are easily adsorbed into liquid steel upon exposure to the air, and argon shrouding alone has limited effectiveness. Previous studies have shown that proper charge sequencing and maintaining a high amount of dissolved oxygen in the melt prior to tapping and deoxidation can limit nitrogen pickup in the melt. In the current study, the effect of melt practice and charging procedure on nitrogen pickup was studied as a function of hold time in a series …

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Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck Jan 2025

Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck

Materials Science and Engineering Faculty Research & Creative Works

The effect of gating system design on the inclusion population and size distribution in an aluminum-killed low-alloy advanced high strength steel casting was studied. A mold with four different gating systems: pressurized and non-pressurized with side risers, naturally pressurized with a side riser, and naturally pressurized with a top riser, was designed using computational fluid dynamics and solidification software. The design allowed inclusion populations in castings produced with each gating system to be compared during the same pouring event. Samples taken from different positions just below the top surface of each casting were analyzed using an SEM/EDS system with automated …

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Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali Jan 2025

Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali

Materials Science and Engineering Faculty Research & Creative Works

Efficient oxide scale removal is critical for maintaining surface quality and process efficiency in steel manufacturing. This study optimizes water jet descaling by evaluating the performance of flat and rotary jet nozzles under varying process parameters. Using a combined approach of experimental analysis and computational fluid dynamics, it investigates the influence of pressure (138–275 bar), lead angle (0°, 15°, 25°), working distance (50–100 mm), and spray angle (15°–25°) on descaling efficiency. Findings indicate that flat jet nozzles achieve superior performance at short working distances due to concentrated impact forces, while rotary jet nozzles sustain efficiency over extended distances through dynamic …

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Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo Jan 2025

Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Vegetable oil-based lubricants have attracted increased research attention in recent decades as sustainable alternatives to conventional petroleum-based lubricants in metal machining. However, more studies are required to fully elucidate the thermo-rheological and tribological properties. This study presents an investigation of the thermo-rheological and tribological properties of different vegetable oils, including low- and high-oleic soybean oil, high-oleic sunflower, safflower, and canola oils. The lubricity, and evolution of viscosity and thermodynamic properties as a function of temperature were investigated to obtain important parameters including the viscosity index, flow behavior index, flow activation energy, specific heat capacity, thermal conductivity, coefficient of friction, contact …

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Ultrafast Belite (Β-C2s) Production Using Biofuel-Based Combustion Synthesis, Shubham Agrawal, Sayee Srikarah Volaity, Oluwadamilare Charles Adesina, Bryan K. Aylas-Paredes, Taihao Han, Srinivas Kilambi, Aditya Kumar, Narayanan Neithalath Jan 2025

Ultrafast Belite (Β-C2s) Production Using Biofuel-Based Combustion Synthesis, Shubham Agrawal, Sayee Srikarah Volaity, Oluwadamilare Charles Adesina, Bryan K. Aylas-Paredes, Taihao Han, Srinivas Kilambi, Aditya Kumar, Narayanan Neithalath

Materials Science and Engineering Faculty Research & Creative Works

This study presents a novel low-temperature, combustion synthesis (CS) approach for the rapid production of belite-rich cements. CS leverages the exothermic heat released from the combustion of biofuels such as lignin and/or biomass, intermixed with pelletized limestone and quartz. At an imposed furnace temperature of ∼700°C (as opposed to 1200°C–1300°C required in a conventional kiln), the source materials are rapidly transformed to belite, resulting in energy, emissions, and economic benefits. This work explores the influence of various process parameters, viz., fuel types and contents, airflow rate, porosity, holding temperature, and holding time on the efficiency of CS-based belite synthesis. Through …

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Development Of Bio-Based Coating Materials For Environmentally Friendly Controlled-Release Nitrogen Fertilizer Applications, Anne Carolyne Mendonca Cidreira Jan 2025

Development Of Bio-Based Coating Materials For Environmentally Friendly Controlled-Release Nitrogen Fertilizer Applications, Anne Carolyne Mendonca Cidreira

Electronic Theses and Dissertations

No abstract provided.

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