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Full-Text Articles in Engineering
Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu
Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper presents the laboratory investigation of properties of warm mix asphalt (WMA) binders and WMA binders containing polyphosphoric acid (PPA).Two types of warm mix additives were used to produce the WMA binders. Superpave tests were carried out on original and short-term aged binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). The results indicated that the WMA binders with different warm mix additives showed different viscosity values, however, the addition of PPA remarkably increased the viscosity values of these two kinds of WMA binders used, in the present study, to a similar …
Factorial Design Approach In Proportioning Prestressed Self-Compacting Concrete, Wu-Jian Long, Kamal Khayat, Guillaume Lemieux, Feng Xing, Wei-Lun Wang
Factorial Design Approach In Proportioning Prestressed Self-Compacting Concrete, Wu-Jian Long, Kamal Khayat, Guillaume Lemieux, Feng Xing, Wei-Lun Wang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In order to model the effect of mixture parameters and material properties on the hardened properties of, prestressed self-compacting concrete (SCC), and also to investigate the extensions of the statistical models, a factorial design was employed to identify the relative significance of these primary parameters and their interactions in terms of the mechanical and visco-elastic properties of SCC. In addition to the 16 fractional factorial mixtures evaluated in the modeled region of -1 to +1, eight axial mixtures were prepared at extreme values of -2 and +2 with the other variables maintained at the central points. Four replicate central mixtures …
Evaluation Of Oxidization Of Crumb Rubber-Modified Asphalt During Short-Term Aging, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab
Evaluation Of Oxidization Of Crumb Rubber-Modified Asphalt During Short-Term Aging, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt binder is subjected to aging during the construction process and service life of pavement. Aging substantially changes the chemical composition and physical properties of asphalt and leads to premature distresses on pavement. It is speculated that crumb rubber modifier (CRM) reduces the susceptibility of asphalt to aging, but its mechanism is not fully understood. Also, the impact of interaction parameters and exchange of components on the aging behavior of a crumb rubber-modified binder is not fully understood. In this study, the effect of CRM on the short-term aging of asphalt was investigated through an analysis of the distinctions between …
Effect Of Crumb Rubber Dissolution On Low-Temperature Performance And Aging Of Asphalt-Rubber Binder, Amir Ghavibazoo, Magdy Abdelrahman
Effect Of Crumb Rubber Dissolution On Low-Temperature Performance And Aging Of Asphalt-Rubber Binder, Amir Ghavibazoo, Magdy Abdelrahman
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt binder plays a critical role in defining the low-temperature performance of asphalt pavement, and, therefore, enhancing its mechanical behavior at low service temperatures through modification always has been of great interest. Crumb rubber modification of asphalt is one of the common practices in the industry. However, the effect of a crumb rubber modifier (CRM) on low-temperature performance of the binder is not well understood. A CRM swells by absorbing the aromat-ics and light molecular components of asphalt at low interaction temperatures (i.e., 160°C) and dissolves at higher interaction temperatures (i.e., 190°C, 220°C). Each of those activities affects the performance …
Freeze-Form Extrusion Fabrication Of Composite Structures, Ming-Chuan Leu, Lie Tang, Bradley K. Deuser, Robert G. Landers, Greg Hilmas, Shi C. Zhang, Jeremy Lee Watts
Freeze-Form Extrusion Fabrication Of Composite Structures, Ming-Chuan Leu, Lie Tang, Bradley K. Deuser, Robert G. Landers, Greg Hilmas, Shi C. Zhang, Jeremy Lee Watts
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A Freeze-form Extrusion Fabrication (FEF) process capable of making three-dimensional (3D) parts and structures with graded composite materials is presented in this paper. The process development includes the design and manufacture of a gantry machine with a triple-extruder mechanism and the associated electronics hardware and computer software for fabricating functionally graded parts from multiple aqueous pastes. A rheological behavior study with Al2O3 paste is performed to identify an efficient binder for transforming the paste into a pseudoplastic with a high yield stress. A green part is first fabricated using the triple-extruder FEF machine in a layer-by-layer manner …
Effect Of Particle Size, Binder Content And Heat Treatment On Mechanical Properties Of 13-93 Bioactive Glass Scaffolds, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Effect Of Particle Size, Binder Content And Heat Treatment On Mechanical Properties Of 13-93 Bioactive Glass Scaffolds, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Particle size, binder content and the post-processing schedule are important parameters that affect the microstructure, and, hence, the mechanical properties of parts produced using the indirect selective laser sintering process. 13-93 bioactive glass, with mean particle sizes ranging from 10 μm to 44 μm, is mixed with different amounts of stearic acid binder to fabricate green scaffolds. Through the design of the post-processing schedule, the time required for postprocessing the green scaffolds is reduced from the initial 80 hrs to 12 hrs. The compressive strength varies from 41 MPa for a part with~60% porosity to 157 MPa for a part …
Optimization Of Selective Laser Sintering Process For Fabrication Of Zirconium Diboride Parts, Ming-Chuan Leu, Shashwatashish Pattnaik, Greg Hilmas
Optimization Of Selective Laser Sintering Process For Fabrication Of Zirconium Diboride Parts, Ming-Chuan Leu, Shashwatashish Pattnaik, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Selective Laser Sintering (SLS) was investigated to fabricate Zirconium Diboride (ZrB2) parts for ultra-high temperature applications. Experiments were conducted to determine values of SLS process parameters (laser power, scan speed, line spacing, and layer thickness) that can be used to build ZrB2 parts with high integrity and sharp geometrical features. A sacrificial plate with a proper number of layers (determined from experimentation) separated from the main part was built in order to reduce thermal gradients when building the main part. The sacrificial plate was found to assist in eliminating cracks in the bottom of the main part. …
Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Bioactive glasses are more promising than biopolymers in fabricating scaffolds for bone tissue repair because they convert to hydroxyapatite, when implanted in vivo. Both direct and indirect selective laser sintering (SLS) methods of 13-93 bioactive glass were considered in this research to study the feasibility of fabricating scaffolds for bone repair applications. Stearic acid was used as the binder in the indirect method to fabricate the scaffolds. The green scaffolds underwent binder burnout and sintering at various soaking conditions between 675⁰C and 700⁰C, achieving a maximum compressive strength of 23.6 MPa, which is higher than that of the human cancellous …
Freeform Fabrication Of Zirconium Diboride Parts Using Selective Laser Sintering, Ming-Chuan Leu, Erik B. Adamek, Tieshu Huang, Greg Hilmas, Fatih Dogan
Freeform Fabrication Of Zirconium Diboride Parts Using Selective Laser Sintering, Ming-Chuan Leu, Erik B. Adamek, Tieshu Huang, Greg Hilmas, Fatih Dogan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Using the Selective Laser Sintering (SLS) process, both flexural test bars and 3D fuel injector components have been fabricated with zirconium diboride (ZrB2) powder. Stearic acid was selected as the binder. Values of SLS process parameters were chosen such that the green parts could be built with sharp geometrical features and that the sintered parts could have good mechanical properties. After binder burnout and sintering, the SLS fabricated ZrB2 test bars achieved 80% theoretical density, and the average flexural strength of the sintered samples was 195 MPa. These values demonstrate the feasibility of the SLS process for …
Controlling Performance Of Crumb Rubber-Modified Binders Through Addition Of Polymer Modifiers, Magdy Abdelrahman
Controlling Performance Of Crumb Rubber-Modified Binders Through Addition Of Polymer Modifiers, Magdy Abdelrahman
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The use of tire rubber as a modifier to enhance the properties of asphalt mixes through the wet process has proved to be a successful procedure, but full control of the properties of crumb rubber-modified binders has been a challenge. The literature indicates a wide variation on adding rubber to asphalt and that the degree of success of rubber modification in AC mixes depends on several factors, the majority of which relate to the method of mixing, storing, and transporting and to construction technologies. Understanding the nature of the interaction process between asphalt cement and crumb rubber-modifier (CRM) helps explain …
Microwave Near-Field Reflection Property Analysis Of Concrete For Material Content Determination, Karl Joseph Bois, Aaron D. Benally, R. Zoughi
Microwave Near-Field Reflection Property Analysis Of Concrete For Material Content Determination, Karl Joseph Bois, Aaron D. Benally, R. Zoughi
Electrical and Computer Engineering Faculty Research & Creative Works
One of the most important parameters associated with concrete is its compressive strength. Currently, there is no reliable nondestructive testing technique that is capable of robust determination of this parameter. Concrete is a heterogeneous mixture composed of water, cement powder, sand (fine aggregate), rocks of various size or grade (coarse aggregate), and air (porosity). Water and cement powder chemically combine into a cement paste binder which, in due curing time (28 days), produces concrete with its specified compressive strength. Compressive strength of concrete is strongly influenced by its water-to-cement (w/c) ratio as well as its coarse aggregate-to-cement (ca/c) ratio. Therefore, …