Digital Commons Network^™

Guest Editors' Note, Kevin Taylor, Johnathan Flowers

Education and Culture

No abstract provided.

Adherence To Selected Air Carrier (Airline) Operational Regulations For Improved General Aviation Flight Safety In Degraded Visibility, Douglas D. Boyd, Mark T. Scharf

Journal of Aviation Technology and Engineering

Introduction: General aviation largely comprises fixed-wing piston-engine light aircraft (,12,500 lbs). Unfortunately, this civil aviation sector suffers a vastly inferior safety record when compared with air carriers (60- to 80-fold higher accident rate). Additionally, such mishaps pose a considerable financial burden to both the affected family and the United States: US$1.64–4.64 billion annually. We hypothesize that this safety disparity partly reflects more stringent operational regulations for air carriers. Herein, we determined whether compliance with six selected air carrier regulations could potentially reduce general aviation accidents in degraded visibility (IMC) the majority of which are fatal. Methods: Accidents (2005–2019) were identified …

Skill And Knowledge Sharing In Cyber-Augmented Collaborative Physical Work Systems With Hub-Ci, Praditya Ajidarma, Shimon Y. Nof

Production, Robotics, and Integration Software for Manufacturing & Management Center

No abstract provided.

Allelopathy: An Eco-Friendly Approach To Control Palmer Amaranth Using Allelopathic Sweetpotato, Varsha Singh, Worlanyo Segbefia, Mary Gracen Fuller, Mark W. Shankle, Callie J. Morris, Stephen L. Meyers, Te-Ming Tseng

Department of Horticulture & Landscape Architecture Faculty Publications

Palmer amaranth (PA) is one of the major weeds in sweetpotato reducing its quantity and quality. The widespread and repeated use of chemical herbicides has led PA to develop resistance for such chemicals. In addition, chemical herbicides are incompatible with the organic production system. It is imperative to find sustainable weed management strategies to provide weed control suitable for organic cultivation and detain the development of herbicide-resistant weeds under conventional crop production. In the present study, seventeen sweetpotato varieties were screened for their allelopathic (weed-suppressing) effect on the growth of PA. The experiment was conducted in a greenhouse using a …

Affective Image Sequence Viewing In Virtual Reality Theater Environment: Frontal Alpha Asymmetry Responses From Mobile Eeg, Claudia Krogmeier, Brandon S. Coventry, Christos Mousas

Purdue University Libraries Open Access Publishing Fund

Background: Numerous studies have investigated emotion in virtual reality (VR) experiences using self-reported data in order to understand valence and arousal dimensions of emotion. Objective physiological data concerning valence and arousal has been less explored. Electroencephalography (EEG) can be used to examine correlates of emotional responses such as valence and arousal in virtual reality environments. Used across varying fields of research, images are able to elicit a range of affective responses from viewers. In this study, we display image sequences with annotated valence and arousal values on a screen within a virtual reality theater environment. Understanding how brain activity responses …

Study On Acoustic Emission Characteristics Of Concrete Freeze-Thaw Damage, Mei Cao

International Conference on Durability of Concrete Structures

Acoustic emission(AE) technology is a dynamic nondestructive testing technology, which is widely used in structural health monitoring and nondestructive testing. In this paper, based on the AE monitoring method, studies the variation laws of mass loss rate, first wave amplitude and AE characteristic parameters of concrete with different freeze-thaw cycles, and analyzes them with the correlation parameter method. The test results show that with the increase of the number of freeze-thaw cycles, the concrete surface spalling is more serious, the mass loss rate increases, and the amplitude of the first wave decreases, indicating that the internal cracks of the concrete …

The Effects Of Curing Temperature On The Hydration Kinetics Of Plain And Fly Ash Pastes And Compressive Strength Of Corresponding Mortars With And Without Nano-Tio2 Addition., Dan Huang, Mirian Velay-Lizancos, Jan Olek

International Conference on Durability of Concrete Structures

Incorporation of fly ash in cementitious systems containing ordinary portland cement (OPC) increases their long-term strength and durability. However, replacement of cement by fly ash also reduces the heat of hydration of such systems and reduces early-age strength development. The reduced rate of strength development can increase the risk of durability problems, e.g. scaling, in cases when young concrete is exposed to low temperatures and deicing chemicals. This study investigated the potential of nano-titanium dioxide (nano-TiO₂) particles to modify the hydration kinetics of fly ash pastes and compressive strength development of corresponding mortars cured under low (4°C) and …

The Degradation Of Concrete Tunnel Wall Panels: A Case Study, Christian Paglia

International Conference on Durability of Concrete Structures

Concrete panels are often used along tunnel walls for technical and aesthetic purposes. Generally, the environment in contact with such materials is aggressive. Emission gases from the vehicles, sulphates, chlorides coming from the winter salt spreading, high temperature and humidity promote an acceleration of the deterioration phenomena. In this work 30 years old concrete panels placed along a 16 km long highway tunnel across the Alps were investigated with respect to their durability. The focus was given to the tunnel entrance zone. This region of the tunnel exhibited a critical environment with respect to the durability of the cementitious material …

End Effect Of Corroded Steel Bar In Concrete Specimen During Corrosion Test By Galvanostatic Method, Peng Zhao, Gang Xu, Qing Wang, Xuan Wang

International Conference on Durability of Concrete Structures

The galvanostatic method is a commonly used accelerated corrosion method in studying the durability of concrete structures caused by steel corrosion. If this method is not adequately controlled, the ends of steel bars will be corroded seriously (this phenomenon is called end effect), which is not common in natural corrosion. How to effectively control the end effect during electrified corrosion is helpful to make the characteristics of electrified corrosion more similar to that of natural corrosion. In this paper, experimental and electromagnetic numerical simulation methods are used to study the influence of cathode and corrosion medium coverage area along the …

Investigation Of Chloride Transportation Mechanism In Reinforced Concrete Specimen Subjected To Eccentric Compression, Yong Dong Yan

International Conference on Durability of Concrete Structures

In order to deal with the chloride ion transportation mechanism in eccentric compressive concrete pier and column in marine environment, stress distribution in the section of eccentric compressive concrete specimen was analyzed firstly, relationship between chloride diffusion coefficient and stress level was developed according to porosity varying under different loads, at last a model of chloride diffusion coefficient under varying stress level was developed. Conversion-diffusion equation in COMSOL Multiphysics was used in this paper to calculate the chloride ion transportation process. Three test beams with different mixture were cast and then loaded to different stress level. After that, all of …

Finite Element Modeling Of Thermal Effect On Airport Slabs, Chuanyue Shen

International Conference on Durability of Concrete Structures

A sub-ground tunnel connecting two concourses of a terminal at Chicago O’Hare International Airport suffered from water leakage. The airport engineers suspected that the problem was caused by high stresses impinging on the tunnel structure by the pavement sections above the tunnel, acting to damage joints and waterproofing membranes that should have prevented such leakage. To provide a fundamental solution to this problem while minimizing the interference with airport operation, a repair strategy needs to be determined based on a clear understanding of the root cause. A preliminary field inspection confirmed that the concrete pavement slabs moved significantly when ambient …

Application Of Multi-Environmental Time Similarity Theory Based On Relative Information (Ri-Mets) Theory In Durability Of Concrete Structures In Marine Chloride Environment, Zhang Kai

International Conference on Durability of Concrete Structures

The Multi-environmental time similarity (METS) method is a testing method that establishes the similarity relationship between the indoor test environment and the on-site environment to evaluate the durability and predict service life of the proposed or under-constructed concrete structure. Based on the METS theory, a similarity ratio of chloride ion concentration and diffusion coefficient between the indoor accelerated environment and the on-site natural environment was established. Then the relative information entropy was introduced into the Multi-Environmental Time Similarity based on Relative Information (RI-METS) theory to consider the time variability of the diffusion coefficient and the surface chloride ion mass fraction. …

Numerical Simulation On The Influence Of Stirrups During Electrochemical Repair, Jiayuan Hu, Keyu Chen, Xin Cheng, Xiaoyu He, Jian Shen, Jin Xia, Weiliang Jin

International Conference on Durability of Concrete Structures

Stirrup in the concrete structure has noteworthy effect on the electrochemical chloride removal (ECR), which was always ignored in the numerical simulation. Taking the impact of stirrup into consideration has disadvantages on improving the accurate of modeling results. In this paper, a three dimensional (3D) numerical model considering the impact of stirrup on ECR treatment was established, and an experiment was numerically studied to explore the validity of the model. The difference between the residual chloride concentration of simulation and experiment in most region of the concrete structure is within ± 25%. Based on this model, the effect of stirrups …

Durability Assessment Of Repairing Vertical Cracks In Concrete Using Microbially Induced Calcium Carbonate Precipitation Technique, Chunhua Lu

International Conference on Durability of Concrete Structures

No abstract provided.

Damage Detection Of Concrete Under Static Loading Based On Ultrasonic Sensor, Dandan Sun

International Conference on Durability of Concrete Structures

In this paper, an ultrasonic sensor for concrete damage detection was designed and prepared. The ultrasonic sensor was used to detect concrete under static load. The results show that the piezoelectric sensor has high sensitivity when the resonant frequency of piezoelectric ceramic is 112kHz and the thickness of alumina matching layer is 1.5mm. As the concrete load increases gradually, the waveform moves backward, and the time for the sensor to receive the waveform becomes longer and the propagation speed becomes slower. When the load force on the concrete test block is small, peak-to-peak value and first wave amplitude decrease rapidly, …

Tensile Performance Of Waterborne Epoxy Coating Immersed In Saline Solutions, Yuqing Dai

International Conference on Durability of Concrete Structures

Organic coatings can greatly improve the resistant abilities against the migration of harmful species into concrete, resulting in the higher durability performances of concrete structures. Therefore, it is essential to assess the engineering performances of organic coatings in the service environments. In this work, the engineering performances and microstructure of a waterborne epoxy that can be used as a component of concrete’s protective coatings were investigated. The waterborne epoxy samples were immersed in tap water, 5wt% NaCl solution and 5% Na₂SO4 solution for 28 d. A direct tensile test equipped with microscopy was conducted to measure the tensile …

Effect Of Ultrafine Supplementary Cemetitious Materials (U-Scm) On The Early Cracking Of Concrete, Hongya Zong

International Conference on Durability of Concrete Structures

Concrete structures are now the most widely used structures, and mass concrete is the most common application of concrete in engineering. Due to the weakness of its own constituent materials, cracks are inevitable due to the inadequacy of the materials themselves, especially in mass concrete. The causes that make concrete crack are mainly divided into two types - load cracks and non-load cracks, and since non-load cracks account for 80% of the total cracks in concrete, the main discussion in this paper is on non-load cracks. After the experiment, it is concluded that in C30, when the proportion of U-SCM …

Effect Of Ultra-Fine Composite Mineral Admixtures On The Mechanical Properties And Slump Of Concrete, Yubo Pan

International Conference on Durability of Concrete Structures

With the technology of the Mineral Admixtures’ application in Cement-based materials becoming mature, the superfinezied of mineral admixtures has also become a trend . After superfinezied, the hydration activity of the mineral admixtures is greatly improved, while increasing the degree of structural compactness of Cement-based materials ,improving the workability of Cement-based materials. The mineral admixtures applying to concrete materials after superfinezied, which has a certain improvement effect on the performance of concrete. In this paper, the effect of superfinezied mineral admixture on the workability of dry hard concrete and the high performance concrete was investigated. The proportion of ultra-fine composite …

Water And Ions Transport In Calcium Silicate Hydrate: A Molecular Dynamics Study, Wei Zhang, Qingrui Yang, Dongshuai Hou, Xingliang Zhang, Yongmin Zhang, Kai Pang, Xiaoxiang Diao

International Conference on Durability of Concrete Structures

Transport properties of water and ions in calcium silicate hydrate (C-S-H) greatly affect the durability of cementitious materials. In this study, molecular dynamics (MD) technique is used to investigate the transport behaviors of NaCl solution in C-S-H nanopores with different sizes (from 0.5 nm to 5 nm), and the hindering effect of C-S-H on the diffusion of water molecules and Cl ions is further explored in the case of a 5 nm pore. Results show that the diffusion coefficients of water molecules and Cl ions in C-S-H nanopores increase with the expansion of nanopore. At the atomic scale, the Ca-rich …

End Effect Of Corroded Steel Bar In Concrete Specimen During Corrosion Test By Galvanostatic Method, Peng Zhao, Gang Xu, Qing Wang, Xuan Wang

International Conference on Durability of Concrete Structures

Corrosion of steel bars is the main durability problem of concrete structures, which seriously endangers the safety and service life of reinforced concrete (RC) structures. When studying such problems, the electrifying corrosion method is often used to obtain corroded components. How to effectively control the corrosion area of steel bars is the key to improve the applicability of the corrosion method. In this paper, experimental and electromagnetic numerical simulation methods are used to study the influence of cathode and corrosion medium coverage area along the longitudinal direction on the corrosion area of steel bar before concrete protective layer corrosion cracking. …

Causes Of Cement Concrete Pavement Diseases In High-Cold And High-Altitude Areas And Progress In Repairing Techniques, Tiejun Hou

International Conference on Durability of Concrete Structures

The climatic characteristics of high-cold and high-altitude areas are low temperature, large temperature differences, and strong ultraviolet radiation. This paper analyzes the causes of cement concrete pavement diseases in high-cold and high-altitude areas and summarizes the common disease types of cement concrete pavements in high-cold and high-altitude areas. Moreover, new repair techniques to improve the maintenance quality of cement concrete pavements in high-cold and high-altitude areas are introduced.

Application Of Acoustic Emission Technology In Monitoring Corrosion Induced Expansion Cracks Of Reinforced Concrete, Zhen Zeng, Gang Xu, Rui Zhang, Zewen Yang

International Conference on Durability of Concrete Structures

Acoustic emission (AE) technology is used to monitor the whole process of reinforced concrete rust expanding and cracking, and the accuracy of AE technology to distinguish the location and type of cracks in concrete rust expanding and cracking is studied and verified. The results show that the protective layer is accompanied by a large number of acoustic emission signals in the process of rust expansion and cracking, Moment tensor inversion can more accurately identify crack sources such as shear source, tensile source and mixed source; In the process of corrosion-induced expansion cracking, shear source cracks appear before tensile source cracks …

Multifunctional Super-Fine Stainless Wire Reinforced Reactive Powder Concrete For Smart Structures, Sufen Dong

International Conference on Durability of Concrete Structures

No abstract provided.

Improving Properties Of Supersulfated Cement By Regulating Its Physiochemical Features Through Nanosio2-Modification, Heng Chen, Pengkun Hou, Xin Cheng Prof.

International Conference on Durability of Concrete Structures

Supersulfated cement (SSC) has been known as a low-carbon cementitious materials due to its low-clinker requirement but high-slag consumption. However, the slow property gain rate, especially at the early ages, together with the long-term drawbacks introduced by the physiochemical characteristics of SSC, has primarily blocked its application. In this work, a novel property-gain regulation technique by applying nanoSiO₂ (NS) modification on the binding system was reported. Firstly, the macro-property of SSCs with NS was presented, and then the hydration features, as well as the physiochemical properties, were reported. It was found that 3 wt.% NS addition could increase the …

Ultra- Ductile Waterborne Epoxy-Concrete Composite Repair Material, Bo Pang, Zuquan Jin, Yunsheng Zhang, Xiaoyun Song

International Conference on Durability of Concrete Structures

With the extension of service time, the building structure is in urgent need of repair and reinforcement due to its deterioration in safety and durability with the years. Normal cement concrete exposes shortcomings such as high brittleness and low flexural-tensile strength for which fails to meet the requirement of construction repairing. In this paper, a novel waterborne epoxy-concrete composite repair material (WECM) was prepared by using self-synthesized water-based epoxy resin based on the molecular structure-activity relationship. The key flexural and tensile performance parameters of WECM were accurately obtained.

Rheological Properties And Structural Build-Up Of 3d Printed Magnesium Potassium Phosphate Cement, Hui Zhi Zhao

International Conference on Durability of Concrete Structures

This paper focuses on the rheological properties of 3D printed magnesium potassium phosphate cements (MKPCs) with different magnesium-to-phosphate (M/P) mass ratio, MgO fineness and supplementary cementitious materials (SCMs) types. The variable shear rate tests were used to monitor the extrudability. The highest slope of the evolution of storage modulus (G') and the maximum static yield stress (M_τs) value were used as an indication of the rigidification rate. The increased M/P mass ratio, MgO fineness and SCMs addition resulted in the promoted structural build-up of 3D printed MKPCs. The consistency between the evolution of G' and M_τs with …

Mechanical Properties Of Engineering Cement-Based Materials Containing Modified Shape Memory Alloy Fiber, Song Mengfan

International Conference on Durability of Concrete Structures

在这项研究中，提出了一种 SMA 纤维的表面改性方法，以改善水泥基复合材料中纤维的界面性能。SMA 纤维涂有 SiO ₂，预计会与 Ca(OH) _2反应由水泥水化形成，减少了薄弱区的可能性，并在纤维-基体界面处形成了更致密的微观结构。采用扫描电子显微镜 (SEM)、能量色散光谱 (EDS) 和红外吸收光谱 (IR) 对表面改性后的 SMA 纤维进行表征。此外，还进行了抗弯强度试验、抗压强度试验和四点弯曲试验，以评价宏观尺度上界面力学性能的增强情况。实验结果表明，包覆的 SiO ₂，导致改性 SMA 纤维-水泥界面处的 CSH 凝胶量增加和孔隙率降低。改性后的SMA纤维与水泥基体之间的紧密粘附有利于建立更强的界面结合力，有利于提高抗弯强度、抗压强度、四点抗弯强度和挠度。抗弯强度、抗压强度、四点抗弯强度和挠度均在28d时显着增加。结果支持了所提出的表面改性方法适用于 SMA 纤维以提高其在工程水泥基材料中的增强效率的结论。

Super-Hydrophobic Hybrid Coatings Preparation Used By Methyltrithoxysilane (Mtes) And Tetraethylorthosilicate(Teos), Quanwei Li

International Conference on Durability of Concrete Structures

超疏水材料由于其优异的疏水自洁性能，在航空航天、海洋工程、除冰防腐等领域具有广阔的应用前景。本文采用简单的溶胶-凝胶制备超疏水涂层。 . 以甲基三乙氧基硅烷（MTES）和原硅酸四乙酯（TEOS）为前驱体，水解缩合后形成粗糙结构，1H,1H,2H,2H-全氟癸基三乙氧基硅烷（FAS）为低表面能的表面活性剂，系统研究了各自的最佳配比零件。涂层的疏水性和形貌分别通过水接触角测量、扫描电子显微镜（SEM）表征。同时，其官能团通过红外光谱表征。基于大量的实验和优化测试，

Effects Of Organic Corrosion Inhibitors On The Performance Of Repair Mortars, Ominda Nanayakkara Dr.

International Conference on Durability of Concrete Structures

Reinforced concrete (RC) structures are severely degraded due to the corrosion of the embedded reinforcing steel, and hence, the upgrading of RC structures is essential. Repairing mortar is widely used to improve durability and strengthen structures; however, further repairing might be required considering the extended life of the structure. The use of inhibitors to protect the reinforcement from corrosion has become of great interest. Therefore, it is vital to study the potential of using corrosion inhibitors in a newly repaired system.

This study investigated the performance of a commercially available polymer-modified mortar with migrating and admixed corrosion inhibitors. The study …

Corrosion Performance Of Embedded Steel Bar In Cl--Contaminated Limestone Calcined Clay Cement (Lc3) At Initial Stage Of Hydration, Weiwen Li, Zuhua Xu, Yaocheng Wang, Xin Wang, Feng Xing

International Conference on Durability of Concrete Structures

Limestone Calcined Clay Cement (LC3) presents brilliant properties in binding Cl^- so that the embedded steel bars are probably protected in Cl^--contaminated condition, which meets the need of sea sand application. However, the corrosion performance of steel bars embedded in LC3 paste with Cl^‑ is unclear, especially in early age hydration. Thus, a series of experiments were carried out to evaluate the corrosion performance of steel bars on initial and hardened stages of hydration, including concentration of OH^- and Cl^- in real pore solution, open circuit potential (OCP) and chemical elements of steel bars. …