Engineering Commons^™

Reliability-Based Conversion Of A Structural Design Code For Railway Prestressed Concrete Sleepers, A M. Remennikov, Martin Murray, Sakdirat Kaewunruen

Faculty of Engineering and Information Sciences - Papers: Part A

"Ballasted railway track is very suitable for heavy-rail networks because of its many superior advantages in design, construction, short- and long-term maintenance, sustainability, and life cycle cost. An important part of the railway track system, which distributes the wheel load to the formation, is the railway sleeper. Improved knowledge has raised concerns about design techniques for prestressed concrete (PC) sleepers. Most current design codes for these rely on allowable stresses and material strength reductions. However, premature cracking of PC sleepers has been found in railway tracks. The major cause of cracking is the infrequent but high-magnitude wheel loads produced by …

Nonlinear Inelastic Behavior Of Circular Concrete-Filled Steel Tubular Slender Beam-Columns With Preload Effects, Vipulkumar Ishvarbhai Patel, Qing Quan Liang, Muhammad N. Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a numerical model based on fiber element formulations for simulating the nonlinear inelastic behavior of eccentrically loaded circular concrete-filled steel tubular (CFST) slender beam-columns with preload effects. Deflections caused by preloads are included in the global analysis of CFST slender beam-columns as initial geometric imperfections. Computational algorithms based on the Müller's method are developed to obtain load-deflection responses of CFST slender beam-columns including preload effects. The accuracy of the numerical model is examined by comparisons of computer solutions with experimental results. The numerical model is utilized to investigate the effects of preloads on the axial load-deflection curves, …

Nonlinear Analysis Of Biaxially Loaded High Strength Rectangular Concrete-Filled Steel Tubular Slender Beam-Columns, Part I: Theory, Qing Quan Liang, Vipulkumar Ishvarbhai Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a new numerical model for the nonlinear inelastic analysis of biaxially loaded high strength thin-walled rectangular concrete-filled steel tubular (CFST) slender beam-columns. The numerical model considers the effects of progressive local buckling, initial geometric imperfections, high strength materials and second order. The accurate fiber element method is used to model the inelastic behavior of composite cross-sections. Theoretical models are developed that simulate the load-deflection responses and strength envelopes of thin-walled rectangular CFST slender beamcolumns under biaxial loads. New computational algorithms based on the M􀂗􁈷 ller's method are developed to adjust the depth and orientation of the neutral …

Hybrid Frp-Concrete-Steel Double-Skin Tubular Columns: Cyclic Axial Compression Tests, Tao Yu, Yu-Bo Cao, Bing Zhang, J G. Teng

Faculty of Engineering and Information Sciences - Papers: Part A

Hybrid FRP-concrete-steel double-skin tubular columns (hybrid DSTCs) are a new form of hybrid columns recently developed at The Hong Kong Polytechnic University. A hybrid DSTC consists of an inner steel tube, an outer FRP tube and a concrete infill between the two tubes. Hybrid DSTCs possess many important advantages over existing column forms, including their excellent corrosion resistance and excellent seismic resistance. While a large amount of research has been conducted on the monotonic behavior of this novel form of columns, only a limited amount of work has been conducted on their behavior under cyclic loading. This paper presents the …

Non-Uniform Stress Distribution In Frp-Wrapped Circular Concrete Columns Under Uniform Axial Deformation, S Q. Li, J F. Chen, Tao Yu, J G. Teng

Faculty of Engineering and Information Sciences - Papers: Part A

The confinement of concrete columns using bonded FRP wraps has become a popular retrofit technique. Through extensive research in the last two decades, many stress-strain models have been developed for concrete in FRP-wrapped circular columns. All these models assume that the stress state is axisymmetric in an FRP-wrapped circular concrete column under concentric axial compression. This implies that the FRP wrap is assumed to be axisymmetric in geometry, but in reality such axisymmetry is not realised due to the existence of an overlapping zone. This paper presents a finite element investigation into the stress state in FRP-wrapped circular concrete columns …

Utilising Non-Composite Steel-Concrete-Steel Panels For Protective Structures, A M. Remennikov, S Y. Kong, Brian Uy

Faculty of Engineering and Information Sciences - Papers: Part A

A high-performance protective structure utilising non-composite steel-concrete-steel (SCS) sandwich panels for protecting buildings and facilities against close-range detonation of VBIEDs and heavy ve-hicle impacts has been developed. Unlike other existing composite sandwich panels, no shear connec-tors between the steel faceplates are utilised to construct protective panels in order to simplify the con-struction process. The concrete core of the panel is included to provide the mass for increased inertia effects, and the steel faceplates are designed to develop tensile membrane resistance at large displace-ment to dissipate impulsive energy. The energy dissipation capability and high ductility of the axially-restrained non-composite SCS panels …

Drying Shrinkage Of Concrete Made From Recycled Concrete Aggregate, B A. Whiting, T J. Mccarthy, E Lume

Faculty of Engineering and Information Sciences - Papers: Part A

Recycled concrete aggregates (RCA) are used in new concrete mixes, termed recycled aggregate concrete (RAC). Among losses in most fresh and hardened properties, literature reports that RAC suffers increased levels of drying shrinkage compared to equivalent mixes incorporating conventional aggregates. This paper describes the procedure and results of a range of experiments conducted on a commercial RCA and its use in new concrete mixes. In particular, this work quantifies the effect 100% RCA has on the drying shrinkage of the resulting concrete. A commercially available RCA was characterised by analysing the particle shape and texture, percentage of solid contaminants, particle …

Behaviour Of Frp Confined Concrete Cylinders Under Different Temperature Exposure, Muhammad N. S Hadi, B A. Louk Fanggi

Faculty of Engineering - Papers (Archive)

Bridge structures are exposed to the elements with a high variation in temperature. The purpose of this study is to investigate the effect of different high temperatures on the behaviour of concrete cylinders wrapped with Fibre Reinforced Polymer (FRP). Twelve concrete cylinders made of 60 MPa having 100 mm diameter and 200 mm height were cast and tested. The cylinders were divided into four groups: cylinders wrapped with a single CFRP layer, cylinders wrapped with two CFRP layers, cylinders wrapped with a single GFRP layer, and cylinders wrapped with two GFRP layers. Each group was exposed to temperatures of 20°C, …

The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed

Dissertations, Master's Theses and Master's Reports - Open

Fly ash has been shown to be an effective replacement for portland cement in concrete mixtures. However, many fly ash materials contain unburned carbon from the combustion process. Unburned carbon in fly ash adsorbs air entraining admixtures (AEAs) reducing their effectiveness in providing a specified air void system in concrete materials. Measurement tools and methods for characterization of the adsorption properties of fly ash materials are necessary for beneficial use of fly ash materials in concrete. In this research, two methods were developed to measure and quantify the adsorption capacity AEAs on fly ash materials. The first method is the …

Strengthening Of Reinforced Concrete Beams Pre-Damaged In Shear, Yousef Mohammed Bachar Chekfeh

Theses

Repair and strengthening of existing reinforced concrete (RC) structures has increased drastically in recent years. Shear reinforcement in RC beams is typically of a small bar diameter, and hence any shear-damage would result in a severe safety hazard and a catastrophic mode of failure especially under extreme loading events. The present work was initiated to the effectiveness of different composite strengthening systems; namely externally bonded carbon fiber reinforced polymer (EB-CFRP), and near surface mounted glass fiber reinforced polymer (NSM-GFRP) to prolong the functional service life of RC beams pre-damaged in shear. It comprised experimental testing and analytical investigation.

The experimental …

Introducing Fly Ash Into Lsi's Recipe, Andrew Mathias Beckrich

All Graduate Theses, Dissertations, and Other Capstone Projects

There has been published data that states that concrete producers can use Fly Ash as an alternative to Portland cement and still generate similar or better strength properties. By applying these principles to our industry and products, what new processes will need to be put in place and followed? What is the correct combination/portion of Fly Ash that will produce similar and better results as well as the adjusted new recipes? What type of cost is associated with the introduction of this new ingredient? Lastly, how does this affect the quality and reputation of the product?

Effects Of High Volume Fly Ash And Powder Activators On Plastic And Hardened Concrete Properties, Drew Alexander Davis

Masters Theses

This study was performed to examine the effects of high volumes of Class C fly ash modified by powder activators upon the plastic and hardened properties of concrete. In a companion study, five Missouri area cements and five Class C fly ashes were examined for incompatibilities, with the most and least reactive combinations being scaled up to full scale concrete testing. Two baseline concrete mixtures were examined, the only difference in mixtures being the sources of portland cement and fly ash. Fly ash replacement was examined at 50% and 70% replacement (by total cementitious mass). Three powder activators were used …

Sensitivity Analysis Of Time/Depth Dependent Chloride Diffusion Coefficient In Concrete, Yung-Ming Sun, Ta-Peng Chang, Ming-Te Liang

Journal of Marine Science and Technology

This paper presents the results for a sensitivity analysis of the time/depth dependent chloride diffusion model in concrete using differential analysis techniques. Four governing prameters of the model are taken to determine the sensitivity of the chloride diffusion coefficient: the time of exposure, inspecting depth, surface chloride concentration, and chloride concetration at the inspecting point. The results of this sensitivity analysis are discussed in detail, including variations in the diffusion coefficient according to the four parameters and the implications for durability design of concrete structures.

Treatment Of Acidic Groundwater In Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, A. Golab, B Guru Prasad

Buddhima Indraratna

Acidic groundwater generated from pyrite oxidation in acid sulfate (AS) soil is a major geoenvironmental problem in Australia. This study aims to evaluate recycled concrete as a reactive material in permeable reactive barriers (PRBs) for the remediation of acidic groundwater in low-lying AS soil floodplains. Laboratory experiments were systematically conducted to investigate the acid neutralization behavior of recycled concrete and its potential to remove dissolved Al and Fe. The results confirmed that recycled concrete could effectively treat acidic groundwater from an AS soil terrain, resulting in near neutral effluent over a long period with complete removal of Al and Fe. …

Evaluating Waste Concrete For The Treatment Of Acid Sulphate Soil Groundwater From Coastal Floodplains, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, Laura Banasiak

Buddhima Indraratna

The treatment of acidic groundwater generated from acid sulphate soil (ASS) terrain is a challenging environmental issue in coastal floodplains of Australia. In this study, a laboratory column experiment was conducted to assess the performance of waste concrete for treating the acidic groundwater leachate from ASS terrain of the Shoalhaven region of NSW. The groundwater was highly acidic (pH of 2.5–3.5) and contained elevated concentrations of iron (10–90 mg/L) and aluminium (30–45 mg/L). Passage of the acidic groundwater through the column filled with waste concrete resulted in a significant improvement in water quality. Reduction in the concentration of iron and …

Development Of A Structured Concrete Thermocline Thermal Energy Storage System, Bradley M. Brown

Graduate Theses and Dissertations

The past couple of decades have shown a concern when considering the way the world obtains its power. The focus has been switching from fossil fuels that have been used for hundreds of years to renewable energy sources, such as the sun. Solar energy is readily and infinitely available for harnessing. One problem with solar energy, though, is its inability to be used during the night time and during cloud covered weather. A solution to this problem is the use of energy storage mechanisms. For solar plants that use solar thermal energy (concentrating solar power plants), thermal energy storage (TES) …

Investigation Into The Role Of Airfield Pavement Deicer In Concrete Pavement Deterioration, David Wingard

All Dissertations

Premature deterioration of concrete due to materials-related distresses has been observed with increased frequency in airfield pavements across the United States in the past two decades. The use of a new breed of deicing chemicals based on alkali-acetates and alkali-formates, starting in the early 1990s, has been suspected to be one of the significant reasons for the increase in the observed deterioration. Previous laboratory-based studies have found that the early-age deterioration in concrete is associated with exposure to deicers causing acceleration of the Alkali Silica Reaction (ASR) deterioration mechanism and consequent failure. However, no systematic forensic studies on the impact …

Retrofit Solutions For Sealed Pervious Concrete Pavements, Gregory Bunting

All Theses

The goal of this research was to design, implement, and evaluate several retrofit solutions for sealed pervious concrete. Properly functioning pervious concrete pavements allow water to drain through the structure, eliminating the need for traditional drainage infrastructure. A recent study of South Carolina porous pavements (Putman 2010) revealed that some pervious concrete pavements are not properly draining, either because of sealing at the surface. Sealed pavements are generally a result of construction processes, and sealed pavements cannot be fixed with sediment removal techniques such as vacuuming and pressure washing. This study investigates a technique to increase infiltration of sealed pervious …

Comparison Of Two Methods For The Assessment Of Chloride Ion Penetration In Concrete: A Field Study, Eric William Ryan

Masters Theses

The currently accepted method for assessing the resistance of concrete to penetration of chloride ions is ASTM C1202, commonly known as the “Rapid Chloride Permeability (RCP) Test.” The test is time-consuming, laborious, has rather high variability, and, is to a degree, user sensitive, making it problematic for inclusion in a performance-based specification. A potential alternative to the RCP test is the “Surface Resistivity (SR) Test”, a method which is dramatically easier, faster, and has less variability than the RCP test. The research reported herein was directed toward determining a correlation between RCP and SR test measurements for Tennessee bridge deck …

Recycling Waste Latex Paint In Overlays, Rigid Pavements, And Pervious Concrete, Oscar Inez Quiroz

UNLV Theses, Dissertations, Professional Papers, and Capstones

With over 16 million gallons of latex paint (WLP) being disposed every year it is the largest by volume, liquid hazardous waste in the United States. WLP is difficult to recycle and hazardous to the environment due to the volatile organic compounds it contains. Several methods exist for disposing WLP including paint swaps, combustion, drying and discarding in a landfill, and by placing pigments in cement. Many communities are moving to dispose WLP by drying and placing in a landfill due to the reduced cost. However, this is the least preferred technique for the environment because it creates a need …

Piedras Blancas Light Station Vista Point Improvement Plan, Larissa Heeren, Reuben Juster, Annamarie Usher, John Rossi, Nick Mitchell

Mechanical Engineering

Piedras Blancas Light station Improvement Involved the design of two separate parking lot/vista point plans as well as the creation of a concrete Iron Ranger located near the gift shop on site.

Gis Based Pavement Maintenance: A Systematic Approach, Robert J. Kmetz

Purdue Polytechnic Directed Projects

Abstract

According to 2008 Federal Highway Administration (FHWA) statistics, there are 2,734,102 miles of paved public roads in the United Sates, with an additional 1,324,245 miles of unpaved public roads. Road conditions deteriorate with time as the result of weather effects, deicing salts, and vehicle loads. The most common pavement distress includes cracking, rutting, and potholes. These pavement defects must be repaired to restore the pavement to a satisfactory service level for road users. According to the FHWA, in 2006 approximately $54.2 billion dollars was spent on maintenance and expansion, just on U.S. highways alone.

Routine maintenance is a cost …

Biodeterioration Of Coastal Concrete Structures By Macro Algae - Ulva Fasciata, Stri Hari Babu Jayakumar, Rama Saravanane, Thirumalai Sundararajan

Journal of Marine Science and Technology

Puducherry is a coastal region in India where the growth of Ulva fasciata (Delile) is very abundant on all marine structures. Though the detrimental effect of this macro algae U. fasciata is a secondary one, its effect has to be investigated. To know its effect, the basic mechanism by which U. fasciata deteriorates concrete structures has been highlighted. To ascertain its detrimental effect on coastal concrete structures, M20 grade concrete cubes were casted and immersed in the coastal area where there is abundant growth of U. fasciata. In addition laboratory simulation has been carried out. Concrete samples collected from the …

Penetration Lag Of Chloride Diffusion Through Concrete Plate Based On Advancing Model, Chih-Hsing Wang, Cho-Liang Tsai, Ching-Chang Lin

Journal of Marine Science and Technology

The solution, based on Neumann's theory, for the content distribution of a diffusion material in a semi-infinite medium is applicable for the case in which a diffusion material diffuses from one side of a plate medium to the other side. After the diffusion material reaches the other side, the penetration rate of the diffusion material is solved using Fick's diffusion law. In this study, concrete plates are manufactured and submerged individually in special containers with saltwater on one side and freshwater on the other side, and no electric charge is applied. The amount of chloride penetrating the plate is monitored. …

Analysis Of Selected Factors Affecting Concrete Cover Measurements On Bridge Decks, Jeffrey Ryan Hoki

Theses and Dissertations

The objective of this research was to quantify the effects of selected parameters on the accuracy of concrete cover measurements on bridge decks. This research involved three full-factorial laboratory experiments each designed to investigate one of three primary variables. These primary variables included distance to a parallel adjacent bar, distance to a reinforcement intersection, and incorrect bar size input for the cover meter. Each experiment also involved four secondary variables known to affect cover readings. These secondary variables included actual cover depth, meter brand, antenna type, and bar size. Statistical analyses were performed to determine the significance of each factor. …

Modeling Of Cfrp-Concrete Interface Subjected To Coupled Pull-Out And Push-Off Actions, Tayyebeh Mohammadi, Baolin Wan, Jian-Guo Dai

Civil and Environmental Engineering Faculty Research and Publications

This paper presents a finite element (FE) modeling method for predicting the IC debonding failure when the FRP/concrete interface is subjected to coupled pull-out (shear) and push-off (dowel) actions. Damaged plasticity model was used to simulate the behavior of concrete close to FRP/concrete interface. A thin damage band exposed to mixed-mode loading condition was modeled separately along the FRP-concrete interface. Cohesive elements were used to model the FRP/concrete interface. A sensitivity analysis was performed to find the appropriate damaged band dimensions, bending stiffness of FRP, and tensile strength of concrete for the model. The numerical results were validated by the …

Development Of Anchorage System For Frp Strengthening Applications Using Integrated Frp Composite Anchors, Geoffrey N. Mcguirk

Masters Theses 1911 - February 2014

Over the past three decades the use of externally bonded fiber reinforced polymer (FRP) materials for structural strengthening applications has become an accepted and widely used method. A primary concern of FRP structural strengthening systems is that the FRP often debonds from the concrete well before the load capacity of the FRP material is reached. In addition, debonding failures are often brittle and occur with little warning. Past research concluded that fastening FRP sheets with FRP anchors is an effective method for delaying or preventing debonding failures. However, there is a clear lack of research pertaining to fastening FRP sheets …

Strength Properties Of Hybrid Nylon-Steel And Polypropylene-Steel Fibre-Reinforced High Strength Concrete At Low Volume Fraction, Hilmi Mahmud

Hilmi Mahmud

The strength properties of hybrid nylon-steel fibre-reinforced concrete were investigated in comparison to that of polypropylene-steel fibre-reinforced concrete, at the same volume fraction (0.5%). The content of the high performance macro structure steel fibres is at 0.4% volume fraction, and the content of micro nylon and polypropylene-fibres is at 0.1% volume fraction. The experimental results show that the compressive strength and splitting tensile strengths and modulus of rupture (MOR) properties of the nylon-steel fibre concrete improved by 3.2, 8.3 and 10.2%, respectively, over those of the polypropylene-steel fibre concrete. On the impact resistance, the first-crack and failure strengths, and the …

Treatment Of Acidic Groundwater In Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, A. Golab, B Guru Prasad

Faculty of Engineering - Papers (Archive)

Acidic groundwater generated from pyrite oxidation in acid sulfate (AS) soil is a major geoenvironmental problem in Australia. This study aims to evaluate recycled concrete as a reactive material in permeable reactive barriers (PRBs) for the remediation of acidic groundwater in low-lying AS soil floodplains. Laboratory experiments were systematically conducted to investigate the acid neutralization behavior of recycled concrete and its potential to remove dissolved Al and Fe. The results confirmed that recycled concrete could effectively treat acidic groundwater from an AS soil terrain, resulting in near neutral effluent over a long period with complete removal of Al and Fe. …

Evaluating Waste Concrete For The Treatment Of Acid Sulphate Soil Groundwater From Coastal Floodplains, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, Laura Banasiak

Faculty of Engineering - Papers (Archive)

The treatment of acidic groundwater generated from acid sulphate soil (ASS) terrain is a challenging environmental issue in coastal floodplains of Australia. In this study, a laboratory column experiment was conducted to assess the performance of waste concrete for treating the acidic groundwater leachate from ASS terrain of the Shoalhaven region of NSW. The groundwater was highly acidic (pH of 2.5–3.5) and contained elevated concentrations of iron (10–90 mg/L) and aluminium (30–45 mg/L). Passage of the acidic groundwater through the column filled with waste concrete resulted in a significant improvement in water quality. Reduction in the concentration of iron and …