Engineering Commons^™

Effect Of Recycled Concrete Aggregates On The Long-Term, Elastic, Total Deflection And Strength Of Precast Prestressed Hollow Core Concrete Slabs, Lizeth Marisol Gomez Santana

Civil Engineering Theses

Concrete constitutes the largest portion of construction and demolition waste generated each year in the United States. The Environmental Protection Agency (EPA) estimates that the total production of construction and demolition of concrete waste during 2015 was 381.8 million tons. In order to reduce the economic and environmental effects of waste concrete, researchers have begun to incorporate it into concrete mixtures. However, the inherent variability in mechanical properties between RCA sources makes it difficult to quantify the maximum permissible replacement of natural aggregate and the end-result properties of concrete. This project investigates the use of recycled concrete aggregates (RCA) obtained …

Thin-Walled Steel Tubular Circular Columns With Uniform And Graded Thickness Under Bidirectional Cyclic Loading, Qusay Al-Kaseasbeh, Iraj H.P. Mamaghani

Civil Engineering Faculty Publications

Thin-walled steel tubular circular columns are becoming an increasingly attractive choice as cantilever bridge piers due to their architectural, structural and constructional advantages. This paper aims to evaluate the strength and ductility of thin-walled steel tubular circular columns with uniform thickness (BC) and graded thickness (BGC) under bidirectional cyclic lateral loading in the presence of constant axial force. The analysis is carried out using a finite-element model (FEM) which is substantiated based on the experimental results in the literature. Then, the proposed BGC column with size and volume of material equivalent to the BC column is investigated. As a part …

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 A Mix Design Adjustment Method For Fiber Reinforced Concrete And Super High Performance Concrete Based On Excess Paste, Joe Malloy

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

The main objective of this study was to develop a mix design adjustment method for Fiber Reinforced Concrete (FRC) that would maintain appropriate workability while improving hardened concrete performance. A literature review was conducted to examine existing methods for adjusting mix designs to account for fiber introduction. It was found that while increasing fine aggregate and cement paste content can make up for lost workability with the addition of fibers, no rational mix design adjustment method is available. Reference mix designs from the Nevada Department of Transportation and the Nebraska Department of Transportation were used, and this study focused on …

Strength And Durability Of Hybrid Fibre Reinforced Binary Blend Geopolymer Concrete, Namasivayam Ganesan, P V Indira, R Sahana

International Conference on Durability of Concrete Structures

This paper deals with an investigation on the influence of hybrid fibres on the strength and durability of binary blend geopolymer concrete. Geopolymer concrete was prepared using Fly ash and GGBS as source material and mix design was carried out as per the guidelines of Professor Rangan of Curtin University, Australia. Different fly ash-GGBS proportions namely 50-50%, 60-40%, 70-30%, 80-20% and 90-10% were considered. The tests on Geopolymer concrete reveal that the compressive strength increases as the percentage of GGBS increases up to 30%. Hence the combination of 70% fly ash and 30% GGBS was considered as a base material. …

Mathematical Modeling Of The Structure Cellular Concrete, Anvar Ishanovich Adilkhodjayev, E.V. Shipacheva, S.S. Shaumarov

Journal of Tashkent Institute of Railway Engineers

The article presents the developed mathematical model of the structure of cellular concrete, which allows one to establish pore sizes and characteristics of inter-pore walls corresponding to the required thermal conductivity and strength of the material, and the results of its numerical implementation are presented

Research Of System Conditions For Formation Of Failure On Mathematical Models By The Results Of The Research Of Reinforced Concrete Bridges, E.T. Yaxshiev, F.Z. Zokirov, A.B. Karimova

Journal of Tashkent Institute of Railway Engineers

Based on the data of field surveys, the results of assessing the state of reinforced concrete span structures of bridges and characteristic defects that occur in the structure during operation are presented. An analysis of the results of inspections and periodic inspections responsible for the operation of artificial structures shows that a significant part of reinforced concrete spans has various types of defects and damage to load-bearing structures. Studies show that defects have a significant impact on the operational properties of reinforced concrete spans, leading both to a limitation of the speed regime of train movements and to the emergence …

Investigated The Strength Of Rolling Stock As A Fuzzy Function, M.L. Waail, R.V. Rahimov

Journal of Tashkent Institute of Railway Engineers

In this paper we use Fuzzy Set Theory to solve one of the essential problems in Railway Engineering: estimate the strength of rolling stock. As known, the strength of, any, rolling stock depends upon several factors that cannot determine them accurately. Therefore, we can consider them as fuzzy factors. The strength of any rolling stock can be changed depending on its operating conditions and the intensive of operation, that can consider as fuzzy factors too. A new proposal method developed depending on Fuzzy Set Theory to estimate the strength of mobile equipment or to compare between several rolling stocks for …

On The Application Of Information Technology For The Development Of Software For Automation The Modeling Process Of Wagons At Wagon Enterprises Jsc "O'Zbekiston Temir Yo'llari", V.P. Bubnov, Sh. Kh. Sultonov

Journal of Tashkent Institute of Railway Engineers

The report presents a functional diagram of the developed software for calculating the values of loads acting on the wagon body. The stages of development and the main modules of a software product that implements mathematical calculations are defined. The issues of the software implementation of the presented algorithms using the object-oriented programming language C # are discussed. The performed engineering analysis using the values of loads obtained using the developed software is given. The developed program in C # language with the use of the integrated Visual Studio environment allows to increase the accuracy and reduce the time for …

Long-Term Performance Of Sustainable Pavements Using Ternary Blended Concrete With Recycled Aggregates, Seth M. Wagner

Theses and Dissertations

The purposes of this study were to (a) design concrete pavement mixtures with recycled concrete aggregates using ternary blends of cementitious materials and a low water-to-binder ratio, (b) measure the fresh and hardened properties of the proposed concrete mixtures and (c) assess the long-term performance of the concrete implementing the use of recycled coarse aggregates. Preliminary investigation into ternary blend combinations via the compressive testing of mortar cubes and isothermal calorimetry was used to predict an optimal blend of cementitious material. Mixes using recycled concrete aggregates at varying replacement rates were tested for fresh and hardened properties using the proposed …

Bandpass: A Smart Resistance Exercise Band To Monitor Strength, Suehayla Mohieldin

ENGS 88 Honors Thesis (AB Students)

Resistance exercise bands are being incorporated into clinical weight loss programs, particularly for older adults, as resistance training can mitigate the trajectory of muscle mass and bone density loss that can occur while dieting. However, adherence to home-based treatments cannot be reliably ascertained by clinicians as there is no method for clinicians to monitor patient compliance outside of the clinic. BANDPASS, a smart resistance band used for exercise, was developed to bridge the gap between clinicians and patients, allowing for easy remote monitoring of patients’ exercise performance. The device integrates a 10kΩ linear potentiometer to TheraBand® tubing. When the user …

Commodity Property Of Carbonate-Ammoniumnitratefertilizers On A Basis Of Ammonium Nitrate Melt And Limestone, N.Yo. Juraev, A.A. Mamataliev, Sh.S. Namazov, R. Radjabov, B.M. Beglov

Chemical Technology, Control and Management

The article studies the process of obtaining carbonate-ammonium nitrate (CAN) based on the mixing of melt ammonium nitrate (NH4NO3) with limestone from the Karmana deposit. In this case, the mass ratio of NH4NO3: CaCO3 varied from 100: 5 to 100: 80. For them, the composition, strength, caking capacity, porosity, absorption of dezilnogo fuel, hygroscopic points, sorption capacity and the dissolution rate of the granules were determined. Any amount of limestone flour dramatically reduces caking, porosity, absorption of diesel fuel, increases strength and dissolution rate of nitrate granules. The results of the sorption capacity of the CAN granules show that both …

Correlations Between Shoulder Rotational Motion, Strength Measures And Throwing Biomechanics In Collegiate Baseball Pitchers, Austin William Higgins

Master's Theses (2009 -)

Pitching involves high stresses to the arm that may alter soft tissue responsible for controlling biomechanics. It has been hypothesized that imbalances in strength and flexibility of the dominant shoulder lead to decreased performance and increased injury risk, but it is not fully known what specific pitching biomechanics are altered. There is a critical need to determine correlations between shoulder rotational strength, range of motion and pitching kinetics. Without such knowledge, identifying potential for injury from shoulder imbalances will likely remain difficult and invasive. The goal of this study was to determine correlations between shoulder rotational strength and range of …

Magnesium Nanocomposites: An Overview On Time-Dependent Plastic (Creep) Deformation, Meysem Haghshenas, Manoj Gupta

Mechanical Engineering Faculty Publications

Magnesium (Mg) nanocomposites are created when nano-size particles are embedded into the Mg (or Mg alloy) matrix. The Mg nanocomposites, cited as high-strength energy-saving materials of future, are a group of emerging materials with excellent combination of strength and ductility and superior specific strength property (strength-to-weight ratio). Having said this, Mg nanocomposites are considered as promising replacement for other structural alloys (i.e. aluminum and titanium) wherever low density and high strength are required, i.e. transportation, aerospace, defense, etc. To be able to apply this group of materials for real components, different failure mechanisms at ambient and elevated temperatures under …

Theoretical Aspects Of Structural And Simulation Modeling Of The Macrostructure Of Composite Building Materials, Anvar Ishanovich Adilkhodjayev, I.M. Mahamataliev, S.S. Shaumarov

Journal of Tashkent Institute of Railway Engineers

At the present time, the description of the joint work of multi-component, high-quality concretes in the framework of the structural and simulation modeling of cement composites is a very topical task of building materials science. In the context of the solution of the above problems, theoretical aspects of structural and simulation modeling are presented on the example of the developed program "Concrete-technology", which allows to predict the strength properties of multicomponent high-quality concrete at the macro structural level.

Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Amorphous SiOC films were synthesized by magnetron sputtering at room temperature with/without radio frequency (RF) bias and further improved in terms of mechanical properties by ion irradiation. As-deposited SiOC films without RF bias exhibit catastrophic failure at a low stress and strain, which is ascribed to microstructural heterogeneities associated with the formation of voids during deposition, as evidenced by transmission electron microscopy. Ion irradiation unifies microstructure accompanied with eliminating the voids, resulting in a simultaneously increase in strength and plasticity (ultimate strength of 5–7 GPa and the strain to shear instability of over 20%). Homogeneous microstructures are demonstrated to ensure …

Technology Of Fastening Metal Columns And Places Adjacent To The Foundation With Bolts, R. Narov

Problems of Architecture and Construction

The strength, connection of junctions and stability of the erected buildings and construction depends on the quality of the seaming of the joints of the steel structure. The connection of junctions consists of the following processes: welding, protection against corrosion and concreting, applying protective coverings.

Atomistic Simulation Studies Of Grain-Boundary Segregation And Strengthening Mechanisms In Nanocrystalline Nanotwinned Silver-Copper Alloys, Xing Ke

Graduate College Dissertations and Theses

Silver (Ag) is a precious metal with a low stacking fault energy that is known to form copious nanoscale coherent twin boundaries during magnetron sputtering synthesis. Nanotwinned Ag metals are potentially attractive for creating new interface-dominated nanomaterials with unprecedented mechanical and physical properties. Grain-boundary segregation of solute elements has been found to increase the stability of interfaces and hardness of nanocrystalline metals. However, heavily alloying inevitably complicates the underlying deformation mechanisms due to the hardening effects of solutes, or a change of stacking fault energies in Ag caused by alloying. For the above reasons, we developed a microalloying (or doping) …

Local-Global Interaction Buckling Of Square High Strength Concrete-Filled Double Steel Tubular Slender Beam-Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

High-strength square concrete-filled double steel tubular (CFDST) slender beam-columns with a circular internal steel tube subjected to eccentric loads may undergo interaction local-global buckling. No computational studies on the interaction local-global buckling of slender square CFDST beam-columns have been reported and their behavior has not been fully understood. This paper describes a mathematical model for the simulation of the interaction local-global buckling behavior of square high-strength CFDST slender beam-columns under axial compression in combination with uniaxial bending. The mathematical model is formulated by the fiber approach, accounting for confinement provided by the internal circular steel tube, and geometric and material …

Investigation Of Engineering Properties Of Normal And High Strength Fly Ash Based Geopolymer And Alkali-Activated Slag Concrete Compared To Ordinary Portland Cement Concrete, Nabeel Farhan, M Neaz Sheikh, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Fly ash-based geopolymer (FAGP) and alkali-activated slag (AAS) concrete are produced by mixing alkaline solutions with aluminosilicate materials. As the FAGP and AAS concrete are free of Portland cement, they have a low carbon footprint and consume low energy during the production process. This paper compares the engineering properties of normal strength and high strength FAGP and AAS concrete with OPC concrete. The engineering properties considered in this study included workability, dry density, ultrasonic pulse velocity (UPV), compressive strength, indirect tensile strength, flexural strength, direct tensile strength, and stress-strain behaviour in compression and direct tension. Microstructural observations using scanning electronic …

Concrete Strength Reduction Due To Over Compaction, Ryan Howes, Muhammad N. S Hadi, Warren J. South

Faculty of Engineering and Information Sciences - Papers: Part B

The purpose of this study was to evaluate the effect of over-compaction on the strength of concrete with regards to commercial and industry practices. Normal concrete, which is commonly used in construction was chosen. Samples were cast using a varying vibration time and testing was performed to determine concrete compressive strength, air content, density and a measure for segregation. These parameters were used to determine the relative sensitivity of concrete to under- versus over-compaction. If segregation was present, it was hypothesized the results would indicate a mathematical relationship between the segregation and strength reduction. This relationship would allow for determination …

Numerical Analysis Of Axially Loaded Circular High Strength Concrete-Filled Double Steel Tubular Short Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Circular high-strength concrete-filled double steel tubular (CFDST) columns are high performance members where the internal and external steel tubes offer significant confinement to the concrete infill. The confinement remarkably improves the concrete compressive strength and ductility. However, no fiber element models have been formulated for computing the responses of CFDST columns with circular steel tubes filled with high-strength concrete incorporating accurate confinement to the core and sandwiched concrete. In this paper, a new fiber-based numerical model is developed that computes the axial load-strain responses of circular high-strength CFDST short columns under axial loading. Based on existing experimental results, a new …

Experimental Evaluation Of Tensile Strength Test Methods For Steel Fibre-Reinforced Concrete, Hussam A. Goaiz, Nabeel Farhan, M Neaz Sheikh, Tao Yu, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

This study presents an experimental evaluation of three different methods for determining the tensile strength of steel fibre reinforced concrete (SFRC). The test methods include the splitting test (ST), double punch test (DPT) and direct tensile test (DTT). The compressive strength of the concrete used in this study ranged between 30 and 80 MPa with 0%, 1·5% and 3% steel fibre by volume of the concrete. In total, 81 concrete cylinders were cast and tested for 28-d compressive strength, splitting tensile strength and double punch tensile strength of the concrete. In addition, 27 concrete prism specimens were cast and tested …

Beta-Type Ti-Nb-Zr-Cr Alloys With Large Plasticity And Significant Strain Hardening, Syed F. Jawed, Chirag D. Rabadia, Y. J. Liu, L. Q. Wang, Y. H. Li, X. H. Zang, Laichang C. Zhang

Research outputs 2014 to 2021

A series of Ti-25Nb-8Zr-xCr (x = 0, 2, 4, 6, 8 wt%) alloys were designed based on DV-Xα cluster method and e=a-Δr diagram with an anticipation to obtain high plasticity and significant strain hardening. The designed alloys were produced through cold crucible levitation melting technique in order to effectively investigate their micro-structures and mechanical properties. The addition of Cr significantly enhances the β stability in the microstructures of the Ti-25Nb-8Zr-xCr alloys. Both yield strength and hardness of the studied alloys increase due to the effect of solid-solution strengthening. By contrast, the plasticity, maximum strength and strain hardening rate are influenced …

Ductile Corrosion-Free Self-Centering Concrete Elements, Maged Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion is a major factor in the deterioration of reinforced concrete (RC) structures. To mitigate this problem, steel bars can be replaced with glass-fiber-reinforced-polymer (GFRP) bars. However, the lack of ductility of GFRP-RC elements has prevented their use in many structural applications, especially in seismic areas. Superelastic shape memory alloy (SMA) bars have been proposed to be used in seismic areas because of their self-centering characteristics. Also, they have the added advantage of being corrosion resistant. This paper examines the combined use of SMA and GFRP bars to achieve ductile self-centering and corrosion-free elements. The first challenge for such a …

Flexural Behaviour Of Superelastic Shape Memory Alloy Reinforced Concrete Beams During Loading And Unloading Stages, Yamen Ibrahim Elbahy, Maged Youssef

Civil and Environmental Engineering Publications

Trend of using smart structures, which can adjust when exposed to severe unexpected loading, is increasing. One of the methods to achieve such structures relies on smart materials. For example, replacing conventional steel reinforcing bars in Reinforced Concrete (RC) structures with superelastic Shape Memory Alloy (SMA) bars significantly reduces the residual deformations caused by post-yielding behaviour. This paper provides in-depth understanding of the flexural behaviour of SMA RC beams. A sectional analysis method, which predicts the flexural behaviour of SMA RC beams during both loading and unloading stages, is adopted and validated using available experimental data. An extensive parametric study …

Effect Of Volcanic Ash Pozzolan Or Limestone Replacement On Hydration Of Portland Cement, Kemal Celik, Craig W. Hargis, Rotana Hay, Juhyuk Moon

Craig Hargis