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Articles 1 - 19 of 19
Full-Text Articles in Architecture
An Experimental Study On Bond Strength Of Reinforcing Steel In High-Volume Fly-Ash Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
An Experimental Study On Bond Strength Of Reinforcing Steel In High-Volume Fly-Ash Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The production of Portland cement-the key ingredient in concrete-generates a significant amount of carbon dioxide. However, because of its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete's contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. an experimental investigation was conducted to compare the bond strength of reinforcing steel in high-volume fly-ash concrete (HVFAC)-concrete with at least 50 % of the cement replaced with fly ash-with conventional concrete (CC). This study investigated two HVFAC mixes [with …
Quantifying The Effect Of Nanoparticles On As(V) Ecotoxicity Exemplified By Nano-Fe2o3 (Magnetic) And Nano-Al2o3, Ji Hu, Demin Wang, Brett E. Forthaus, Jianmin Wang
Quantifying The Effect Of Nanoparticles On As(V) Ecotoxicity Exemplified By Nano-Fe2o3 (Magnetic) And Nano-Al2o3, Ji Hu, Demin Wang, Brett E. Forthaus, Jianmin Wang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Nano-Fe2O3 (magnetic) and nano-Al2O3 are increasingly used in biomedical fields for cellular labeling and drug delivery, and in the industry as catalysts. However, they may also serve as carriers of toxic contaminants and negatively impact the environment and human health. in the present study, Ceriodaphnia dubia was used to assess the toxicity of these nanoparticles (NPs) with and without the presence of background arsenic(V) (As[V]). the results showed that although these NPs alone did not exhibit significant toxicity in the experimental concentration range, they could significantly enhance the toxicity of As(V). the accumulation of …
Influencing Factors On The Dynamic Properties Of Organobentonites, Bate Bate, Susan Burns
Influencing Factors On The Dynamic Properties Of Organobentonites, Bate Bate, Susan Burns
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The dynamic responses of soils are important engineering properties, especially for soils with high organic contents, because these soils can underlie critical support structures such as highway bridges or levees. Consequently, the initial tangent shear modulus (Gmax), secant shear modulus ratio (G/Gmax), and damping ratio (D) are important parameters in evaluating the dynamic soil behavior for soils subjected to earthquake, wind, waves, traffic, and equipment vibration. in this study, these dynamic properties of organ bentonites were quantified experimentally using resonant column tests. the results from this study were evaluated in terms of the effect of shear strain, organic content, and …
Effect Of Scc Mixture Composition On Thixotropy And Formwork Pressure, A. F. Omran, Kamal H. Khayat, Y. M. Elaguab
Effect Of Scc Mixture Composition On Thixotropy And Formwork Pressure, A. F. Omran, Kamal H. Khayat, Y. M. Elaguab
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
High lateral pressure exerted on formwork systems by self-consolidating concrete (SCC) is one of the hindrances for using such highly flowable concrete in cast-in-place applications. Self-consolidating concrete is a complex system that can be made using a wide range of mixture proportioning and often incorporated various chemical admixtures and supplementary cementitious materials. the investigation of the effect of each material ingredient independently on lateral pressure of SCC is not a simple task. in this study, thixotropy is rather used to assess the effect of various mixture parameters on formwork pressure. Thixotropy is determined by the evaluation of the structural buildup …
Statistical Modelling Of The Coupled Effect Of Mix Design And Rebar Spacing On Restricted Flow Characteristics Of Scc, Yahia Ammar, Khayat H. Kamal, Sayed Mohammed
Statistical Modelling Of The Coupled Effect Of Mix Design And Rebar Spacing On Restricted Flow Characteristics Of Scc, Yahia Ammar, Khayat H. Kamal, Sayed Mohammed
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Self-consolidating concrete (SCC) is designed to exhibit high deformability and stability to maintain homogenous suspension of coarse aggregate particles in the mortar during flow to ensure adequate passing ability of the concrete through restricted areas and the filling of the formwork without any consolidation. Proper deformability and uniform suspension of coarse aggregate particles in the matrix are key parameters to ensure successful casting and adequate in situ performance. the required flow properties of concrete are affected by the rheological properties of the mixture and the characteristics of the cast element, including the level of reinforcement. the mixture proportioning of SCC …
Dendrochemistry Of Multiple Releases Of Chlorinated Solvents At A Former Industrial Site, Jean Christophe Balouet, Joel Gerard Burken, Frank Karg, Don Vroblesky, Kevin T. Smith, Håkan Grudd, Anders Rindby, François Beaujard, Michel Chalot
Dendrochemistry Of Multiple Releases Of Chlorinated Solvents At A Former Industrial Site, Jean Christophe Balouet, Joel Gerard Burken, Frank Karg, Don Vroblesky, Kevin T. Smith, Håkan Grudd, Anders Rindby, François Beaujard, Michel Chalot
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Trees Can Take Up and Assimilate Contaminants from the Soil, Subsurface, and Groundwater. Contaminants in the Transpiration Stream Can Become Bound or Incorporated into the Annual Rings Formed in Trees of the Temperate Zones. the Chemical Analysis of Precisely Dated Tree Rings, Called Dendrochemistry, Can Be Used to Interpret Past Plant Interactions with Contaminants. This Investigation Demonstrates that Dendrochemistry Can Be Used to Generate Historical Scenarios of Past Contamination of Groundwater by Chlorinated Solvents at a Site in Verl, Germany. Increment Cores from Trees at the Verl Site Were Collected and Analyzed by Energy-Dispersive X-Ray Fluorescence (EDXRF) Line Scanning. the …
An Experimental Study On Bond Strength Of Reinforcing Steel In Self-Consolidating Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
An Experimental Study On Bond Strength Of Reinforcing Steel In Self-Consolidating Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental investigation was conducted to compare the bond strength of reinforcing steel in self-consolidating concrete (SCC) with conventional concrete (CC). This study investigated two different compressive strengths of SCC as well as CC. the experimental program consisted of 24 pull-out specimens as well as 12 full-scale beams (three for each concrete type and strength). the pull-out specimens were based on RILEM recommendations, and the beam specimens were tested under a simply supported four-point loading condition. the CC test results served as a control and were used to evaluate the results from the SCC pull-out and beam specimen tests. Furthermore, …
Behavior Of Segmental Precast Posttensioned Bridge Piers Under Lateral Loads, Haitham Dawood, Mohamed Elgawady, Joshua Hewes
Behavior Of Segmental Precast Posttensioned Bridge Piers Under Lateral Loads, Haitham Dawood, Mohamed Elgawady, Joshua Hewes
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Abstract a segmental precast posttensioned (SPPT) bridge pier is an economic recentering structural system. Understanding the seismic behavior of a SPPT system is an important step toward its application in high seismic zones. This paper presents a detailed three-dimensional finite-element (FE) model that was developed using the ABAQUS platform. a brief description and discussion of cyclic tests on eight large-scale SPPT piers is also presented. Four of the piers were constructed and tested to a predefined degree of damage. Then, these piers were retrofitted and retested. the FE models developed and presented in this paper predicted the backbone curves of …
Behavior Of Full-Scale Rc T-Beams Strengthened In Shear With Externally Bonded Frp Sheets, Abdeldjelil Belarbi, Sang Wook Bae, Antonio Brancaccio
Behavior Of Full-Scale Rc T-Beams Strengthened In Shear With Externally Bonded Frp Sheets, Abdeldjelil Belarbi, Sang Wook Bae, Antonio Brancaccio
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Recently many research studies have investigated the shear behavior of reinforced concrete (RC) beams strengthened with fiber-reinforced polymer (FRP) composites. However, most were conducted on small-scale specimens. Thus, analytical models and design equations developed from those studies may not predict the actual behavior of large-scale RC beams strengthened with FRPs. in this study, an experimental study was performed on this topic using full-scale RC T-beams in order to understand the behavior of full-scale bridge beams strengthened in shear with FRP. the main parameters investigated in this study were the transverse steel reinforcement ratio and the effect of mechanical anchorage systems. …
Multinomial Logistic Regression Model For Single-Vehicle And Multivehicle Collisions On Urban U.S. Highways In Arkansas, Ghulam Bham, Bhanu S. Javvadi, Uday R.R. Manepalli
Multinomial Logistic Regression Model For Single-Vehicle And Multivehicle Collisions On Urban U.S. Highways In Arkansas, Ghulam Bham, Bhanu S. Javvadi, Uday R.R. Manepalli
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Multivariate analysis can be used to identify the effects of several factors on the causes of a crash compared with univariate analysis. This paper uses a multivariate-analysis technique, the multinomial logistic regression (MLR) model, to examine the differences in crash-contributing factors for six collision types for both divided- and undivided-highway nonjunctions, given that a crash has occurred. Multinomial logistic regression was used to investigate (1) single-vehicle and (2) multivehicle collisions, which included (1) angular, (2) head-on, (3) rear-end, (4) sideswipe-same-direction, and (5) sideswipe-opposite-direction collisions. the risks associated with different collision types were found to be significantly influenced by various vehicle …
Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz
Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Self-consolidating concrete (SCC) has the potential to significantly reduce costs associated with concrete construction. SCC is a highly flowable, Non segregating concrete that has a variety of advantages over conventional concrete (CC). However, SCC is not without its problems, which can include increased creep and shrinkage, as well as decreased bond and shear strength. the goal of this research project was to evaluate the creep, shrinkage, and shear behavior of a chemically Based SCC mix. One of the benefits of a chemically Based approach is the potential to eliminate the negative side effects of many SCC mixes. the investigation included …
High-Volume Fly Ash Concrete For Sustainable Construction, Jeffery S. Volz
High-Volume Fly Ash Concrete For Sustainable Construction, Jeffery S. Volz
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
With worldwide production of fly ash approaching 800 million tons annually, increasing the amount of fly ash used in concrete will remove more material from the solid waste stream and reduce the amount ending up in landfills. However, most specifications limit the amount of cement replacement with fly ash to less than 25 or 30%. Concrete with fly ash replacement levels of at least 50% - referred to as high-volume fly ash (HVFA) concrete - offers a potential green solution. the following study investigated the structural performance of HVFA concrete compared to conventional Portland-cement concrete. Specifically, the research examined both …
Monotonic Behavior Of Mississippi River Valley Silt In Triaxial Compression, Shuying Wang, Ronaldo Luna
Monotonic Behavior Of Mississippi River Valley Silt In Triaxial Compression, Shuying Wang, Ronaldo Luna
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The static behavior of Mississippi River Valley silt was characterized using triaxial compression testing. Silt specimens, especially over consolidated ones, showed dilation behavior. There was no unique critical state among specimens with different over consolidation ratios (OCRs). with OCRs of 1, 2, and 8, the specimens exhibited normal behavior and dilated more as effective consolidation pressure dropped. However, for an OCR of 4, the specimens showed opposite behavior and dilated more as effective consolidation pressure rose. the friction angle of the silt was computed on the basis of several failure criteria, and the limiting strain was found to be the …
Factors Influencing Crack-Induced Tensile Strength Of Compacted Soil, Tae Hyung Kim, Tae Hoon Kim, Gi Chun Kang, Louis Ge
Factors Influencing Crack-Induced Tensile Strength Of Compacted Soil, Tae Hyung Kim, Tae Hoon Kim, Gi Chun Kang, Louis Ge
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Mode I (tensile) fracture is the most commonly observed failure in Geostructure's resulting from cracks in soil. Direct or indirect tensile tests have been used to evaluate the tensile strength of geomaterials. in this paper, the unconfined penetration device and experimental procedure were modified to reduce measurement errors. It was then used to determine the tensile strength of compacted soil. Factors influencing the tensile strength of the compacted soil, including the plasticity index, rate of loading, and size of specimen were discussed in detail, as well as its reliability. Experimental results indicated that the modified, unconfined penetration technique is sufficiently …
Time-Weighted Average Spme Analysis For In Planta Determination Of Cvocs, Emily M. Sheehan, Matt A. Limmer, Philipp Mayer, Ulrich Gosewinkel Karlson, Joel Gerard Burken
Time-Weighted Average Spme Analysis For In Planta Determination Of Cvocs, Emily M. Sheehan, Matt A. Limmer, Philipp Mayer, Ulrich Gosewinkel Karlson, Joel Gerard Burken
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The Potential of Phytoscreening for Plume Delineation at Contaminated Sites Has Promoted Interest in Innovative, Sensitive Contaminant Sampling Techniques. Solid-Phase Microextraction (SPME) Methods Have Been Developed, Offering Quick, Undemanding, Noninvasive Sampling Without the Use of Solvents. in This Study, Time-Weighted Average SPME (TWA-SPME) Sampling Was Evaluated for in Planta Quantification of Chlorinated Solvents. TWA-SPME Was Found to Have Increased Sensitivity over Headspace and Equilibrium SPME Sampling. using a Variety of Chlorinated Solvents and a Polydimethylsiloxane/carboxen (PDMS/CAR) SPME Fiber, Most Compounds Exhibited Near Linear or Linear Uptake over the Sampling Period. Smaller, Less Hydrophobic Compounds Exhibited More Nonlinearity Than Larger, More …
An Improved Prediction Model For Spacecraft Damage Following Orbital Debris Impact, Joel E. Williamsen, William P. Schonberg
An Improved Prediction Model For Spacecraft Damage Following Orbital Debris Impact, Joel E. Williamsen, William P. Schonberg
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper offers a new set of 'generic', data-Based hole size and crank length prediction models for spherical orbital debris particles impacting multi-plate targets at velocities up to ~12 km/s. the equations are applicable to a wide variety of spacecraft target configurations, but are limited to hole sizes above, but relatively near, the ballistic limit of the impacting particles. Additional work is underway to expand these models to diameters farther above the ballistic limit for the described shield types.
Effects Of Nano-Copper(Ii) Oxide And Nano- Magnesium Oxide Particles On Activated Sludge, Guoqiang Liu, Jianmin Wang
Effects Of Nano-Copper(Ii) Oxide And Nano- Magnesium Oxide Particles On Activated Sludge, Guoqiang Liu, Jianmin Wang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Effects of nano-copper (II) oxide (nano-CuO) and nano-magnesium oxide (nano-MgO) particles on activated sludge endogenous respiration (aerobic digestion), biochemical oxygen demand (BOD) biodegradation, and nitrification were investigated through respiration rate measurement. for comparison, the effects of Cu (II) and Mg (II) ions on activated sludge were also studied. Results indicated that soluble Cu (II) has half maximum inhibitory concentration (IC50) values of 19, 5.5, 53, and 117 mg Cu/L for endogenous respiration, BOD biodegradation, ammonium oxidation, and nitrite oxidation, respectively. However, nano-CuO only inhibited BOD biodegradation at 240 mg Cu/L or more, and its associated toxicity was primarily caused by …
Long-Term Performance Of Passive Materials For Removal Of Ozone From Indoor Air, C. J. Cros, Glenn C. Morrison, J. A. Siegel, R. L. Corsi
Long-Term Performance Of Passive Materials For Removal Of Ozone From Indoor Air, C. J. Cros, Glenn C. Morrison, J. A. Siegel, R. L. Corsi
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The health effects associated with exposure to ozone range from respiratory irritation to increased mortality. in this paper, we explore the use of three green building materials and an activated carbon (AC) mat that remove ozone from indoor air. We studied the effects of long-term exposure of these materials to real environments on ozone removal capability and pre- and post-ozonation emissions. a field study was completed over a 6-month period, and laboratory testing was intermittently conducted on material samples retrieved from the field. the results show sustained ozone removal for all materials except recycled carpet, with greatest ozone deposition velocity …
Shake Table Testing Of A Utility-Scale Wind Turbine, Ian Prowell, Chia Ming Uang, Ahmed Elgamal, J. Enrique Luco, Lanhui Guo
Shake Table Testing Of A Utility-Scale Wind Turbine, Ian Prowell, Chia Ming Uang, Ahmed Elgamal, J. Enrique Luco, Lanhui Guo
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Shake table tests were undertaken on a full-scale wind turbine (65-kW rated power, 22.6-m hub height, and 16-m rotor diameter) using the Network for Earthquake Engineering Simulation Large High Performance Outdoor Shake Table at the University of California, San Diego. Structural response characteristics and modal parameters are presented for base shaking imparted in two configurations, both parallel (configuration 1) and perpendicular (configuration 2) to the axis of rotation of the rotor. Results are summarized for a series of progressively stronger motions imparted in configuration 1, with analysis identifying damage sources leading to an overall loss in stiffness. Two sources of …