Civil Engineering Commons^™

Crack Control And Bond Performance Of Alternative Coated Reinforcements In Concrete, Sachin Sreedhara

All Dissertations

Concrete cracking in structures is a ubiquitous problem which can lead to the deterioration of the structure. Other than affecting the strength aspect of a structure, cracking impacts the serviceability criteria as well. Although cracking phenomenon in any structure is highly inevitable, it has to be minimized in order to maintain a structure’s life effectively. Cracking in reinforced concrete structures is related to the bond strength developed between the bar and the concrete. It also depends on an ability of the bar to resist the stresses due to shrinkage to minimize the crack. Another important aspect is the resistance offered …

Wind Flow Characteristics Of Multi-Vortex Tornadoes And Their Wind Effects On Residential Houses, Yi Zhao

Doctoral Dissertations

"Tornadoes strike the USA very frequently, with an average of 1200 reports per year, and the average annual tornado-induced property loss has reached $10B. The devastation from recent tornadoes have prompted a renewed interest in better understanding tornado dynamics, their interactions with the built environment, and the performance of civil structures during tornadoes. In the past, the wind effects caused by single-vortex tornadoes have been widely studied, while the multi-vortex tornadoes were rarely considered. In fact, many previous deadly, costly tornadoes involved multiple vortices. Therefore, it is important to understand the wind flow characteristics of multi-vortex tornadoes in order to …

Evaluation Of The Chloride Ions Penetration Into Concrete Structure With The Surface Penetrants Served In Cold Marine Environment For 20 Years, Yanhua Kuang, Yuki Sakoi Associate Professor, Naoto Takashima Postgraduate, Minoru Aba Professor, Yoichi Tsukinaga Professor,

International Conference on Durability of Concrete Structures

The intrusion of chloride ions in concrete served in the marine environment is the leading cause of corrosion of steel bars. This paper examined the result of a long-term survey on the actual structure (the Tomakomai breakwater) treated with a set of penetrants partly. The survey was conducted twice, in the 12th and 20th years after construction.

The results showed that the penetrants could effectively reduce the penetration of chloride ions into concrete. After using the penetrants, the calculated surface chloride ion concentration was decreased by 5.04%/72.18% (the 12th year/the 20th year). As the service years increase, surface chloride ion …

Efficiency Of Bank Filtration In The Removal Of Cyanotoxins Under Different Levels Of Nutrients, Luke Walkenhorst

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

Harmful Algal Blooms (HABs) are an increasing concern not only in Nebraska, but across the world. Increasing global temperatures in conjunction with overuse of synthetic fertilizers are leading causes to the increasing frequency and concern of HABs. In the present work, the effectiveness of simulated bank filtration (BF), as an economical water treatment option, to remove cyanotoxins under different levels of nutrients (nitrates and phosphates) was investigated. Vertical flow-through columns pre-acclimated with two levels of nutrients (e.g., nitrate and phosphate—10 vs. 50 mg/L) were exposed to two different levels of cyanotoxins (10 vs. 75 μg/L). Results from the study confirmed …

Autonomous Vehicles On The Smart Roads: Challenges And Potentials, Laura Cristancho, Baleki Campbell, Mahyar Amirgholy

The Kennesaw Journal of Undergraduate Research

Self-driving vehicles and smart roads are not new concepts. These ideas have been discussed for many years but for much of this time, the required technology was not available to make them a reality. Just recently has our technology caught up to our ideas and we are beginning to see progress towards the realization of the automated highway system. As the transition to a complete automated system is still in progress, this leaves many questions that still need to be answered as well as allowing for novel solutions to be presented. Using modern research papers to formulate a sound basis …

Wetland Soil Development Along Salinity And Hydrogeomorphic Gradients In Active And Inactive Deltaic Basins Of Coastal Louisiana, Amanda Fontenot

LSU Master's Theses

Coastal wetlands provide an abundance of ecosystem services that benefit society, such as essential habitat for commercial species, storm protection, nutrient cycling, and carbon storage. Louisiana faces rapid rates of relative sea level rise (natural subsidence and eustatic sea levels) that threaten wetland survival, which are amplified by a reduction of riverine sediment input. An important determining factor of marsh survival is the formation of wetland platform elevation, known as vertical accretion, which is determined by several processes including sediment deposition & erosion, below ground biomass (BGB) productivity, decomposition of organic matter, shallow & deep subsidence, and soil compaction. Feldspar …

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 …

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. …

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.

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. …

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.

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. …

Investigation On The Properties Of Calcium Sulfoaluminate Cement Waterproof Repair Mortar Modified With Ethylene-Vinyl Acetate Powder, Dong Dong

International Conference on Durability of Concrete Structures

本文采用乙烯-醋酸乙烯酯（EVA）粉体和CSA水泥制备了防水修复砂浆，并对其水化和性能进行了研究。结果表明，EVA粉体延长了凝固时间，提高了防水修补砂浆的流动性，使其在实际工程中更容易应用。EVA粉提高了防水修复砂浆的不渗透性，降低了吸水性。虽然EVA粉降低了防水修补砂浆的抗弯强度和抗压强度，但它仍然符合JC/T 2381-2016标准对刚性修复砂浆的要求。EVA粉体降低了防水修复砂浆的收缩率，改善了界面过渡区和拉伸粘接强度、弯曲粘接强度等粘接性能。EVA粉末抑制CSA水泥的水合作用6 h，在3 d水化年龄时抑制作用消失。

Influence Of Biological Sulfuric Acid On Corrosion Mechanism Of Alkali-Activated Cement Concrete, 季 韬 教授

International Conference on Durability of Concrete Structures

生物硫酸对碱活化水泥混凝土腐蚀机理的影响

丁方硕、韬骥、潘伟杰

福州大学土木工程系

抽象的

讨论了不同浓度的生物硫酸对碱活化水泥混凝土（AACC）腐蚀的影响，并以化学硫酸为参考。AACC的质量和抗压强度、孔溶液的pH曲线和Ca ²⁺对其释放进行了研究，并通过 ESEM-EDS 和 XRD 揭示了 AACC 的腐蚀机理。结果表明，在不同浓度的化学硫酸和生物硫酸作用下，AACC的腐蚀产物主要是石膏。随着硫酸浓度的增加，AACC的失重率增加，AACC的抗压强度降低。石膏阻碍化学硫酸进入混凝土。然而，石膏为细菌提供了生存环境，细菌很容易渗透到混凝土中，加速了AACC的破坏。与化学硫酸相比，生物硫酸增加了AACC的质量损失率和抗压强度。

参考

荣H，Wu，C.，Ma，G.，Zheng，X.，和Liu，Z，2021。污水环境下混凝土微生物腐蚀研究进展。中国陶瓷学会学报，49（5）：988-999。

Scholz, F., 1997。微生物影响的材料腐蚀：科学和工程方面。固态电化学杂志，1（2）：181-181。

谢毅，林，X.，吉，T.，2019。普通硅酸盐混凝土与碱活化混凝土在生物硫酸侵蚀下的耐腐蚀机理比较。建筑和建筑材料，228（20）：1-12。

Frost Resistance And Pore Structure Properties Of Mortar Containing Air Entraining Agent Combined With Superabsorbent Polymer, Yanqun Xu, Qiang Yuan

International Conference on Durability of Concrete Structures

The air entraining effect of air entraining agent (AEA) is deeply affected by environment, which will further influence its function of improving frost resistance. To solve this problem, a strategy of using AEA combined with superabsorbent polymer(SAP) to improve the frost resistance of mortar was proposed in this study. Mass loss and relative dynamic elastic modulus of mortar were used to characterize frost resistance of mortar. Air void density, spacing factor, air void distribution and air content were measured to analyze its pore structure properties. The results verify that the combined use of AEA and SAP can improve the frost …

The Transportation Of Corrosion Products In Cementitious Material Under Chloride-Rich Environment, Yuzhou Wang

International Conference on Durability of Concrete Structures

Corrosion products, forming on steel bar in cementitious material, can lead to concrete cracking. Clear the transportation of corrosion products is of great significance to predict corrosion-induced structural deterioration. This study investigates the corrosion products in steel-reinforced concrete specimen. By Raman spectroscopy and SEM method, the chemical constituents and micromorphology of corrosion products at steel-concrete interface as well as those inside the pore of cement paste are investigated. The proportion of corrosion products filling into the cement paste is determined by EDTA titration method. The results reveal that corrosion products diffuse in forms of ion in solution under chloride-rich environment, …

Research On Water Absorption And Frost Resistance Of Concrete Coated With Different Impregnating Agents For Ballastless Track Structure, Xin Ge, Yanbin Tan, Xiaowei Wang, Yongjiang Xie, Qinfei Li, Linxiang Li, Lu Yang, Zhongwei Feng

International Conference on Durability of Concrete Structures

In consideration of performance requirement of ballastless track concrete in cold regions of China, 3 types of commercially available impregnating agents were employed to research their effect on water absorption and frozen resistance of concrete, containing silanes, potassium silicate and osmotic curing agent. The results presented that coating silanes was the most effective on the reduction of water absorption among all employed impregnating agents, because of the most significant character change of concrete surface from hydrophilicity to hydrophobicity which could be proved by the contact angle test of concrete. The promotion on frozen resistance of concrete was not as significant …

Study On Corrosion Resistance Of Portland Cement-Calcium Sulphoaluminate Cement Binary System In A Sodium Chloride Environment, Shilin Song, Tao Xing, Yu Zhang, Jianzheng Wang, Xiaodong Shen, Ying Ma

International Conference on Durability of Concrete Structures

Portland cement is widely used in civil engineering. However, Portland cement-based materials are easy to be corroded by seawater in marine environment. Many research show the corrosion resistance of Portland cement mortar can be improved by add appropriate amount of mineral admixture.Sulphoaluminate cement have high strength and good corrosion seawater resistance. However, the short setting time and high hydration heat of sulphoaluminate cement limit its application in civil engineering.Portland cement-sulphoaluminate cement (PC-CSA) not only have high strength and corrosion resistance but also long setting time.In this work, the sulphoaluminate cement was used to partially replace Portland cement. The replacement level …

Predicting Tensile Strength For Prestressed Reinforced Concrete-Driven Piles, Thuyet N. Nguyen, Thang Pham, Thuy Vu, Adnan A. Malik, Duc N. Dinh

Civil Engineering Faculty Publications

Reinforced concrete piles installed by impact hammers have been used as a common solution for deep foundations because they are cost effective and require less time for construction. Driven piles are often used in large volumes for infrastructure and industrial projects in rural areas. Unlike other installation methods, installing piles using impact hammers can generate tensile stress during construction, which can result in pile failures. Induced tensile stress occurs when piles are being driven through a hard soil layer to a softer soil layer, and transverse cracks happen when induced tensile stress exceeds the pile tensile strength. This issue is …

Anthropogenic Stressors Compound Climate Impacts On Inland Lake Dynamics: The Case Of Hamun Lakes, Arash Modaresi Rad, Jason Kreitler, John T. Abatzoglou, Kendra Fallon, Kevin R. Roche, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Inland lakes face unprecedented pressures from climatic and anthropogenic stresses, causing their recession and desiccation globally. Climate change is increasingly blamed for such environmental degradation, but in many regions, direct anthropogenic pressures compound, and sometimes supersede, climatic factors. This study examined a human-environmental system – the terminal Hamun Lakes on the Iran-Afghanistan border – that embodies amplified challenges of inland waters. Satellite and climatic data from 1984 to 2019 were fused, which documented that the Hamun Lakes lost 89% of their surface area between 1999 and 2001 (3809 km² versus 410 km²), coincident with a basin-wide, multi-year …

Performance Modeling And Analysis Of A Thermoelectric Building Envelope For Space Heating, Xiaoli Liu, Ming Qu, Kazuaki Yazawa, Jorge Kohanoff, Piotr Chudzinski, Lorenzo Stella, Brian Norton, Niall Holmes Dr., Ruchita Jani, Hongxi Yin

Conference papers

To provide energy-efficient space heating and cooling, a thermoelectric building envelope (TBE) embeds thermoelectric devices in building walls. The thermoelectric device in the building envelope can provide active heating and cooling without requiring refrigerant use and energy transport among subsystems. Thus, the TBE system is energy and environmentally friendly. A few studies experimentally investigated the TBE under limited operating conditions, and only simplified models for the commercial thermoelectric module (TEM) were developed to quantify its performance. A holistic approach to optimum system performance is needed for the optimal system design and operation. The study developed a holistic TBE-building system model …

Structural Health Monitoring Of Fatigue Cracks For Steel Bridges With Wireless Large-Area Strain Sensors, Sdiq Anwar Taher, Jian Li, Jong-Hyun Jeong, Simon Laflamme, Hongki Jo, Caroline Bennett, William N. Collins, Austin Downey

Faculty Publications

This paper presents a field implementation of the structural health monitoring (SHM) of fatigue cracks for steel bridge structures. Steel bridges experience fatigue cracks under repetitive traffic loading, which pose great threats to their structural integrity and can lead to catastrophic failures. Currently, accurate and reliable fatigue crack monitoring for the safety assessment of bridges is still a difficult task. On the other hand, wireless smart sensors have achieved great success in global SHM by enabling long-term modal identifications of civil structures. However, long-term field monitoring of localized damage such as fatigue cracks has been limited due to the lack …

The Effects Of Recycled Waste On Concrete Mixture Properties, Noral Hadbawi

Master of Science in Civil Engineering Theses

Recent years have seen an exponential increase in plastic product consumption worldwide. Manufacturing, and individuals rely on plastics in almost every aspect, as a result, a negative impact on the environment is detected due to the large quantities and low biodegradability of plastic waste. The massive amount of plastic waste and end-of-life tires produced annually required a vast area of landfills, which became a major concern far and wide. To address these issues, an eco-friendly approach consisting of incorporating plastic and rubber waste into engineering applications, such as plastic concrete, and rubberized concrete was proposed. A primary objective of this …

A Deep Learning Image Segmentation Model For Agricultural Irrigation System Classification, Ehsan Raei, Ata Akbari Asanjan, Mohammad Reza Nikoo, Mojtaba Sadegh, Shokoufeh Pourshahabi, Jan Franklin Adamowski

Civil Engineering Faculty Publications and Presentations

Effective water management requires a large-scale understanding of agricultural irrigation systems and how they shift in response to various stressors. Here, we leveraged advances in Machine Learning and availability of very high resolution remote sensing imagery to help resolve this long-standing issue. To this end, we developed a deep learning model to classify irrigation systems at a regional scale using remote sensing imagery. After testing different model architectures, hyper parameters, class weights and image sizes, we selected a U-Net architecture with a Resnet-34 backbone for this purpose. We applied transfer learning to increase training efficiency and model performance. We considered …

Impact Of Stormwater Infiltration On Rainfall-Derived Inflow And Infiltration: A Physically Based Surface–Subsurface Urban Hydrologic Model, Kun Zhang, Anthony J. Parolari

Civil and Environmental Engineering Faculty Research and Publications

The subsurface fate of stormwater infiltration enhanced by green infrastructure (GI) is unknown. GI redirects stormflows from the surface into the subsurface, which can be partitioned to evapotranspiration or baseflow, or be intercepted by buried infrastructure trenches. Stormwater that infiltrates sanitary sewer pipes is referred to as rainfall-derived inflow and infiltration (RDII) and represents a rapid pathway for infiltrated stormwater to reach receiving waters. To quantify the partitioning of infiltrated stormwater between slow and fast flows, a physically-based hydrologic model was developed integrating coupled surface–subsurface processes and urban sewer systems and applied to a sewershed near Milwaukee, WI. In this …

Influence Of Rainfall-Induced Erosion On The Stability Of Sandy Slopes Treated By Micp, Shihui Liu, Kang Du, Kejun Wen, Catherine Armwood-Gordon, Lin Li

Civil and Architectural Engineering Faculty Research

As an environmentally friendly technology, microbially induced calcite precipitation (MICP) is widely used to improve the engineering properties of soil. The goal of this study was to investigate the effect of rainfall-induced erosion on the stability of sandy slopes which were treated by MICP technology. The observation of the erosion pattern of low concentration (0.25 M Ca) and high concentration (0.5 M Ca) of MICP-treated slopes, the mechanical behaviors of MICP-treated and cement-treated samples, and the effects of rainfall-induced erosion on the roughness of 0.5 M Ca MICP-treated and 10% cement-treated slope were studied through visual observation, unconfined compressive tests, …