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Full-Text Articles in Engineering
Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani
Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani
Civil Engineering ETDs
The time-dependent rheological and early-age strength parameters of Polymer concrete (PC) were investigated. PC flow decreased, and the static yield stress and thixotropy increased as the specimen aged, while the dynamic yield stress remained unchanged. The study found that the Herschel-Bulkley model can accurately describe the PC’s rheological behavior over time. The change in cohesion strength and internal friction angle over time was observed using uniaxial unconfined compression and direct shear tests of fresh PC. A time-dependent MohrCoulomb failure criterion was established. Temperature analysis was used to determine the gel time and explain the evolution of the time-dependent early-age strength …
Investigation Into The Load Transfer Mechanism Of Trees To Develop An Innovative Foundation Configuration Using 3d Finite Element Modeling, Kaleb Boland
All Theses
This study was inspired by a tree’s reliance on its root system that enables it to withstand a natural disaster, such as an extreme hydroclimatic event or hurricane. This curiosity has led to an investigation into what makes this possible, developing a new and innovative foundation configuration for infrastructure systems, and a new possible construction material and method. This study provides results on a material that does not have conventional testing procedures or standards: a tree root. The trees studied are common to the upstate of South Carolina, which are Pine, Sweetgum, and White Oak. According to the results, on …
Design And Predicting Performance Of Carbon Nanotube Reinforced Cementitious Materials : Mechanical Properties And Dispersion Characteristics., Mahyar Ramezani
Design And Predicting Performance Of Carbon Nanotube Reinforced Cementitious Materials : Mechanical Properties And Dispersion Characteristics., Mahyar Ramezani
Electronic Theses and Dissertations
Recently, Carbon Nanotubes (CNTs) are drawing considerable attention of researchers for reinforcing cementitious materials due to their excellent mechanical properties and high aspect ratio (length-to-diameter ratio). However, CNTs might not disperse well within the cement matrix, resulting in little improvement or even degradation of concrete properties. The uncertainty in producing the consistent results in different studies might be attributed to multiple interactions between the experimental variables affecting the nanotube dispersion and the final properties of CNT-cement nanocomposites. Therefore, this research mainly focused on proposing equations that can reliably capture these interactions in order to correlate CNT dispersion with the mechanical …
Eco-Efficient Preplaced Recycled Aggregate Concrete Incorporating Recycled Tire Waste Rubber Granules And Steel Wire Fibre Reinforcement, Saud A. Alfayez
Eco-Efficient Preplaced Recycled Aggregate Concrete Incorporating Recycled Tire Waste Rubber Granules And Steel Wire Fibre Reinforcement, Saud A. Alfayez
Electronic Thesis and Dissertation Repository
With increasing world population and urbanization, the depletion of natural resources and generation of waste materials is becoming a considerable challenge. As the number of humans has exceeded 7 billion people, there are about 1.1 billion vehicles on the road, with 1.7 billion new tires produced and over 1 billion waste tires generated each year. In the USA, it was estimated in 2011 that 10% of scrap tires was being recycled into new products, and over 50% is being used for energy recovery, while the rest is being discarded into landfills or disposed. The proportion of tires disposed worldwide into …
Mechanical Properties Of Inconel 718 Processed Using Electron Beam Free Form Fabrication (Ebf3), Brent R. Waters
Mechanical Properties Of Inconel 718 Processed Using Electron Beam Free Form Fabrication (Ebf3), Brent R. Waters
Theses and Dissertations
Electron beam freeform fabrication (EBF3) is a rapid metal deposition process that works efficiently with the wieldable alloy Inconel 718 (IN 718). EBF3 is a developing additive manufacturing (AM) process that can manufacture IN 718 parts directly from computer aided design (CAD) data. EBF3 can produce parts significantly faster and more energy efficient than competing IN 718 AM technologies. The EBF3 process utilizes metal wire feedstock which is induced into a molten pool using a focused electron beam in a vacuum environment. This allows parts to be built layer by layer, creating intricate shapes that …
Mechanical Characterization Of Polymer Concrete With Nanomaterials, Alaeddin Douba
Mechanical Characterization Of Polymer Concrete With Nanomaterials, Alaeddin Douba
Civil Engineering ETDs
Nanomaterials are defined by those whose characteristic length scale lies within the nanometer scale. Their extreme dimension achieves extraordinary mechanical properties superior to other micro and macro additives. The introduction of nanotechnology to Civil Engineering utilizes low volume inclusions of nanomaterials to alter the properties of conventionally used bulk materials. Polymer Concrete (PC) where epoxy polymer binders replace cement binders, has become a common repair material among many other application and often can be considered an alternative to Portland cement concrete (PCC). PC is often used in bridge deck overlays, manholes, machine foundations and repairs. Its diverse chemical composition and …
Functionalized Graphitic Nanoreinforcement For Cement Composites, Nima Zohhadi
Functionalized Graphitic Nanoreinforcement For Cement Composites, Nima Zohhadi
Theses and Dissertations
Physical and mechanical properties of graphitic nanomaterials, in particular multiwalled carbon nanotubes (MWCNTs) and graphene nano-platelets (GNPs) make them promising candidates for nanoreinforcement of cement composites. The two key challenges associated with the incorporation of MWCNTs and GNPs are to attain uniform dispersion and interfacial bonding within the composite matrix. The effects of three main-stream dispersion techniques (namely, ultrasonication, acid-etching, and surfactant-coating) on the mechanical properties and microstructure of MWCNT- and GNP-cement composites were experimentally studied. Compressive strength tests and different characterization techniques including dynamic light scattering, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission …
A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo
A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo
Theses and Dissertations
Rapid Prototyped part failure constitutes a major issue for both RP providers and customers. When parts fail the reputation of the vendor is heavily deteriorated, customer dissatisfaction increase and replacement of the broken parts is often necessary to avoid the loss of future business. Product design teams often run into situations where Rapid Prototyped parts are not able to withstand shipping and handling and delivered broken or while demonstrating and examining the parts. When done in the face of customers this builds a perception of poor quality and lack of aptitude on the design group as well as the RP …
Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson
Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson
Theses and Dissertations
Interlocking Cross Laminated Timber (ICLT) wall panels are a new wood construction product similar to Cross Laminated Timber panels. Besides being an innovative structural system, they also utilize beetle killed timber from many of the forests that have been devastated by the Mountain Pine Beetle. Three tests were performed on three ply ICLT panels measuring 8 feet (2.44m) wide, 8 feet (2.44m) tall and 8.5 inches (21.6cm) thick to determine the racking, flexural and axial strengths of the wall panels. After each test was performed the walls were disassembled and investigated for cause of failure. Using the data from the …
Synthesis And Characterization Of Geopolymers For Infrastructural Applications, Jian He
Synthesis And Characterization Of Geopolymers For Infrastructural Applications, Jian He
LSU Doctoral Dissertations
In this study, the synthesis process, composition, and microstructure as well as mechanical properties of geopolymers generated by 3 different kinds of raw materials (i.e., metakaolin, mixture of red mud and fly ash, mixture of red mud and rice husk ash) was explored. For geopolymers from identical raw materials, variable parameters involved in the synthesis were examined to investigate the extent and degree of geopolymerization. Uniaxial compression testing was used to examine the mechanical properties (i.e. compressive strength, stiffness, and failure strain). Then the composition and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) as well …
Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam
Performance Of Nevada’S Aggregates In Alkali-Aggregate Reactivity Of Portland Cement Concrete, Mohammad Shahidul Islam
UNLV Theses, Dissertations, Professional Papers, and Capstones
Alkali-aggregate reaction (AAR) is a form of distress that occurs in concrete and results in serviceability problems, cracks, spalling, and other deterioration mechanisms. There are two categories of AAR, namely, alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Alkali-silica reaction is one of the most recognized deleterious phenomena in concrete, and has been a major concern since its discovery in the 1940s. The reaction which occurs between reactive silica or silicates present in some aggregates and alkalis of Portland cement produces an alkali-silica gel that expands in the presence of moisture resulting in concrete cracks. ACR is also a chemical reaction …