Structural Engineering Commons^™

A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation, Marzuki Silalahi, Hanif Abdurrahman Wicaksana, Ferhat Aziz, Syahfandi Ahda, Mohamad Riza Iskandar

Makara Journal of Technology

Micropowders of oxide-dispersion-strengthened (ODS) steel have been synthesized using the ultrasonic irradiation method with variations in amplitude. The ultrasonic irradiation process is performed for 50 h at a frequency of 20 kHz with 40%, 50%, and 60% amplitudes in toluene solution. The formation of Fe-Cr microalloys in the preparation of Fe- 15Cr-0.5Y2O3 powder was analyzed using SEM-EDS, X-ray diffraction (XRD), and TEM-EDS. The percentage of Fe- Cr phase mass fraction of ODS steel micropowder formed during ultrasonic irradiation with 40%:50%:60% amplitude was 12.2%:34.1%:22.1%, with 25.67:77.02:38.51 nm crystallite size. The crystallite size at 50% amplitude was the largest, and the diffusion …

Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite, Engkir Sukirman, Yosef Sarwanto, Syahfandi Ahda, Andon Insani

Makara Journal of Technology

Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed …

Evaluation Of Fracture Principles In Asphalt Concrete Utilizing The Sc(B) Geometry, Airam Marlee Morales Vega

Graduate Theses and Dissertations

Since cracking is one of the principal distresses to be considered in asphalt concrete, multiple fracture tests and geometries have been used to quantify cracking resistance. One of the most popular geometries that have been used in fracture tests is the Semi-Circular bend (SC(B)). However, for this geometry, most of the fracture test methods use different parameters such as thickness, testing temperatures, and loading rates. Thus, the purpose of this research was first to evaluate fracture energy by performing a ruggedness test based on ASTM E1169. Then, to apply fracture mechanics concepts to evaluate three specimen thicknesses (25, 50, and …

Incorporating Geophysical Data In Slope Stability Modeling For Two Slopes In Arkansas, Vanessa Lebow

Graduate Theses and Dissertations

Slope failures in the United States alone cause millions of dollars in damage to infrastructure, threaten national monuments, create environmental hazards, and take an average of 25-50 lives a year. With the inevitable construction that occurs on slopes, it is imperative that the slopes be properly designed which requires a thorough understanding of slope grade, subsurface soil conditions, soil strength parameters, water table locations, and depth to bedrock across the entire site. The preferred method of data collection would be to use borings and other in-situ methods; however, sometimes due to cost constraints or site accessibility only a very limited …

Evaluation Of Concrete Deck Curing Regimens Using Capillary Pressure Sensing System, Samuel Spann

Graduate Theses and Dissertations

Early-age plastic shrinkage cracking is a common problem with the construction of concrete bridge decks due to the high surface area-to-volume ratio and exposure to potentially detrimental environmental effects. Curing regimens are utilized to mitigate cracking risk during the plastic stage of the concrete; the curing regimens evaluated for this study were wet burlap-polyethylene sheeting, two acrylic curing compounds, and one lithium compound. Capillary pressure in the water filled pores has been shown to correlate to the plastic shrinkage cracking risk of concrete. A new portable system has been developed to measure the capillary pressure that could potentially be used …

Truck Activity Pattern Classification Using Anonymous Mobile Sensor Data, Taslima Akter

Graduate Theses and Dissertations

To construct, operate, and maintain a transportation system that supports the efficient movement of freight, transportation agencies must understand economic drivers of freight flow. This is a challenge since freight movement data available to transportation agencies is typically void of commodity and industry information, factors that tie freight movements to underlying economic conditions. With recent advances in the resolution and availability of big data from Global Positioning Systems (GPS), it may be possible to fill this critical freight data gap. However, there is a need for methodological approaches to enable usage of this data for freight planning and operations.

To …

Study Of Internal Strains Developed In Concrete Decks At Early Ages In Steel Continuous Bridges, Fernando R. Benitez Ortiz

Graduate Theses and Dissertations

The Arkansas Department of Transportation (ARDOT) has identified bridge deck cracking shortly after concrete decks are placed and prior to applying traffic loads. Previous researchers have confirmed improper construction practices and design methods can lead to deck cracking. Currently, many contractors throughout Arkansas are using continuous deck pours. This construction approach may restrict the concrete slab from movement during early age shrinkage, causing tensile stresses to develop. The final stresses at the end of construction must be lower than the concrete tensile strength, if not cracking issues will develop. Eventually, these cracks may enlarge due to service load stresses and …

Behavior Of Hollow-Core Composite Bridge Columns Having Slender Inner Steel Tubes, Mohanad M. Abdulazeez, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper experimentally investigates the seismic behavior of three large-scale hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) columns. An HC-FCS column consisted of a concrete shell sandwiched between an outer glass fiber-reinforced polymer (GFRP) tube and an inner steel tube. Both tubes provided continuous confinement for the concrete shell along with the height of the column. The columns had two different steel tube diameter-to-thickness (Ds/ts) ratios of 85, and 254. Each steel tube was embedded into the footing, with an embedded length of 1.25-1.6 times its diameter, while the GFRP tube was not embedded into the footing. Two columns were tested as as-built …

Review On Rheological Characterization Of Bio-Oils/Bio- Binders And Their Applicability In The Flexible Pavement Industry, Ahmed Hemida, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper mainly presents a qualitative review on to what extent the bio-oil has the potential to replace asphalt binder for a sustainable, flexible pavement industry. The current research comprises reviews on the rheological characterization of pure bio-oils and bio-oil modified binders (bio-binders) investigated in the literature. The literature showed that several sources of bio-oils have the potential to contribute to the flexible pavement industry. This research mainly discusses the high-temperature properties, especially viscosity for the construction process (mixing and compaction) and viscoelasticity for the elevated temperature of in-service roads. This review paper encourages orientation towards these kinds of renewable …

Multifunctional Lightweight Aggregate Containing Phase Change Material And Water For Damage Mitigation Of Concrete, Wenyu Liao, Aditya Kumar, Kamal Khayat, Hongyan Ma

Materials Science and Engineering Faculty Research & Creative Works

This paper presents an innovative concept of multifunctional lightweight aggregate, which is produced by loading phase change material (PCM) into the interior of lightweight sand (LWS) and sealing the surface pores using water. The PCM loaded in the LWS functionalizes it as a temperature management agent in concrete, and the water in surface pores enables internal curing. It has been found that the particle shape and pore structure of crushed expanded shale LWS makes it an ideal carrier for PCM, loading sufficient PCM and maintaining better (compared to natural sand) mechanical interlocking. When coupled with the internal curing effect, the …

Development Of Finite Element Techniques To Simulate Concrete-Filled Fiber-Reinforced Polymer Tube Structures, Hakeem S. Majeed

Electronic Theses and Dissertations

This dissertation presents the development of finite-element (FE) techniques to simulate the behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) in support of more effective structural design and analysis methods for buried composite arch bridges (BCABs) that use CFFT arches as main structural members. The research includes three specific topics to make contributions in different aspects of the investigation of these complex structures.

The first topic is the nonlinear three-dimensional FE modeling of steel-free CFFT splices. For model validation, comparisons were made between the model predictions and control beam and spliced beams with and without internal collars tested by …

Investigating The Addition Of Suicide Prevention Barriers To The Natchez Trace Parkway Bridge, Jaideep Thota, Nancy Abdo, Payne Susong, Connor Campbell, Joseph Allston, Meet Patel

Chancellor’s Honors Program Projects

No abstract provided.

Safety Assessment Of Road Vehicle In Crosswind Considering Driver Behavior, Jiexuan Hu

LSU Doctoral Dissertations

With expansion of the economy, more and more highway networks extend to coastal areas and mountain valley areas. Vehicles will be exposed to strong crosswinds when driven on these highway roads, especially in hurricane season and in winter in these two different topographic areas. Strong crosswinds threaten the safety of transportation infrastructure and passing vehicles in forms of vehicle accidents that usually result in traffic blockage and driver injury, posing negative effects on economic growth. This dissertation aimed to evaluate the vehicle safety when running through crosswinds in consideration of driver behaviors.

Firstly, the aerodynamic characteristics of road vehicles were …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

Conditional Survival Analysis For Concrete Bridge Decks, Azam Nabizadeh, Habib Tabatabai, Mohammad A. Tabatabai

Civil and Environmental Engineering Faculty Articles

Bridge decks are a significant factor in the deterioration of bridges, and substantially affect long-term bridge maintenance decisions. In this study, conditional survival (reliability) analysis techniques are applied to bridge decks to evaluate the age at the end of service life using the National Bridge Inventory records. As bridge decks age, the probability of survival and the expected service life would change. The additional knowledge gained from the fact that a bridge deck has already survived a specific number of years alters (increases) the original probability of survival at subsequent years based on the conditional probability theory. The conditional expected …

Pore Characteristics And Computed Permeability Of Pastes Subject To Freeze-Thaw Cycles At Very Early Ages By X-Ray Ct, Ya Wei, Zehong Wu, Xiang Gao

International Conference on Durability of Concrete Structures

Freeze-thaw cycling can damage microstructure of concrete and reduce the service life of concrete structures. This is especially detrimental for concrete subject to freeze-thaw cycles at very early-ages, such as within the first few days after constructions. Typical low and high water-to-cement (w/c) ratio pastes are investigated experimentally and numerically in this study. The pastes are subject to freeze-thaw cycles at the age of 1, and 7 days and then sealed-cured to the age of 45 days. The pore size distribution is measured and quantified by X-ray computer tomography (CT) with high resolution. The permeability of the corresponding pastes is …

Development Of Engineered Cementitious Composites With Conductive Inclusions For Use In Self-Sensing Applications, Benny Suryanto Dr, Danah Saraireh Ms, Steven Walls Mr, Jaehwan Kim Dr, W John Mccarter Prof

International Conference on Durability of Concrete Structures

The mechanical and a.c. electrical properties of a new varietal of engineered cementitious composite (ECC) incorporating conductive inclusions are presented. Electrical measurements were undertaken over a wide frequency range while curing and when under uniaxial tensile loading to study the influence of ongoing hydration and multiple microcrack formation on the composite electrical impedance. When presented in Nyquist format, the work shows that conductive inclusions reduce the bulk resistance of the composite while enhancing its polarizability, transforming the classic, single-arc bulk response of typical cement-based materials to a two-arc response. The bulk resistance was shown to increase with time and damage, …

Rehabilitation Of Low Rise Rcc Structure Along 9m High Retaining Wall, Aniruddha Nakhawa Er, Vivek Deshmukh Dr

International Conference on Durability of Concrete Structures

Mumbai is the financial, commercial and entertainment capital of India, facing bigger challenges in accommodating its over growing population day by day. The Mumbai City has population of 18.4 million over its 634 km2 area, ie. Almost 350 ft2/person. This enormous rise in population density has restricted the development to expand vertically. This also, results in growth of major slums, which is almost 62% of the population dwelling in slums. Subsequently, the authorities is in need of a large scaled Slum Sanitation Program, which utilize the scarcely available land for construction of Community Toilet Blocks with involvement of NGO’s and …

Residual Service Life Estimation And Its Importance For Pretensioned Concrete (Ptc) Bridges In Coastal Cities, Dyana Joseline, Deepak K. Kamde, Sripriya Rengaraju, Radhakrishna G. Pillai

International Conference on Durability of Concrete Structures

Many pre-tensioned concrete (PTC) bridges are experiencing premature chloride-induced corrosion. Hence, it is crucial to estimate their residual service life and update it with newer data on a periodic basis - to plan for corrosionpreventionorcontrolmeasuresandensuresafetyofexistingbridges.Criticalchloridethreshold(Cl th) is one of the parameters necessary to estimate the corrosion initiation period. However, quantitative estimates on Clth for prestressing (PS) steel are not well-reported in literature. This paper presents experimental data on the Clth of PS steel, the chloride diffusion coefficient (Dcl), and surface chloride concentration (Cs) of concrete samples obtained from a PTC bridge girder in a coastal city in India. For estimation …

Mechanical And Microstructure Characteristics Of Concrete-Mixtures Designed For Durability Of Rc-Structures In Corrosive Environment, Saeid A. Alghamdi Dr., S. Ahmad, M. M. Khaled

International Conference on Durability of Concrete Structures

As exposures to chloride-salts are known as prime factors causing initiation and continuity of corrosion-process of steel reinforcement bars in reinforced concrete (RC) structures, it has always been a major concern for designers considering the requirements of structural-durability for targeted-service life of RC-structures in aggressively corrosive environments typically prevalent in coastal regions. Research works previously reported by the researchers have modeled corrosion-process in terms of corrosion-current density, and it was realized that concrete-mixtures design quality and characteristics, degree of exposures to corrosive-agents such as chloride salts, and protective-concrete cover-thickness are now known beyond doubt to be determinant factors as regards …