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Full-Text Articles in Other Civil and Environmental Engineering

Multiscale Modeling Of Fracture In Quasi-Brittle Materials Using Bifurcation Analysis And Element Elimination Method, Keyvan Zare Rami Dec 2019

Multiscale Modeling Of Fracture In Quasi-Brittle Materials Using Bifurcation Analysis And Element Elimination Method, Keyvan Zare Rami

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

Analyzing the fracture of heterogeneous materials is a complex problem, due to the fact that the mechanical behavior of a heterogeneous material is strongly dependent on a variety of factors, such as its microstructure, the properties of each constituent, and interactions between them. Therefore, these factors must be effectively taken into account for accurate analysis, for which the multiscale method has been widely used. In this scheme, the computational homogenization method is used to obtain the effective macroscopic properties of a heterogeneous material based on the response of a Representative Volume Element (RVE). The growth of damage in an RVE …


Development Of A Mix Design Adjustment Method For Fiber Reinforced Concrete And Super High Performance Concrete Based On Excess Paste, Joe Malloy Dec 2019

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 …


Optimizing The Valorization Of Industrial By-Products For The Induction Healing Of Asphalt Mixtures, Amir Tabakovic, Marta Vila-Cortavitarte, Daniel Jato-Espino, Daniel Castro-Fresno Aug 2019

Optimizing The Valorization Of Industrial By-Products For The Induction Healing Of Asphalt Mixtures, Amir Tabakovic, Marta Vila-Cortavitarte, Daniel Jato-Espino, Daniel Castro-Fresno

Articles

Self-healing within asphalt pavements is the process whereby road cracks can be repaired automatically when thermal and mechanical conditions are met. To accelerate and improve this healing process, metal particles are added to asphalt mixtures. However, thisapproach is costly both in economic and environmental terms due to the use of virgin metallic particles. So, even though the self-healing of asphalt mixtures has been widely addressed in experimental terms over the years, there is a lack of research aimed at modelling this phenomenon, especially with the purpose of optimizing the use of metal particles through the valorization of industrial by-products. As …


Uhpc Shear Keys In Concrete Bridge Superstructures, Craig Newtson, Brad Weldon, Elsy Flores, Jordan Varbel, William Toledo Aug 2019

Uhpc Shear Keys In Concrete Bridge Superstructures, Craig Newtson, Brad Weldon, Elsy Flores, Jordan Varbel, William Toledo

Publications

This research investigated the use of locally produced ultra-high performance concrete (UHPC) as a grouting material to repair deteriorated shear keys. Shear keys are used in adjacent girder superstructures to produce monolithic behavior and load transfer across the structure. Shear key durability is a concern since shear key degradation can jeopardize the integrity of the structure. Transportation agencies have reported that 75% of distress in adjacent girder bridges is due to cracking and de-bonding along shear keys. Previous research has shown that locally produced UHPC has excellent mechanical and durability properties. UHPC has also been shown to have good bonding …


The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen Feb 2019

The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Induction healing is a proven technology which is able to improve the self‐healing capacity of asphalt concrete. Healing is achieved via electromagnetic current produced by passing induction machine, where steel asphalt constituents heat up which in turn soften the bitumen in the asphalt layer, allowing it to flow and close cracks, repairing the damage. This paper reports on the study which investigated the influence of ageing on the healing capacity of Porous Asphalt (PA) concrete. Porous Asphalt concrete mix was prepared first, then subjected to an accelerated (laboratory) ageing process using a ventilated oven. In order to further evaluate the …


Optimization Of The Calcium Alginate Capsules For Self-Healing Asphalt, Shi Xu, Amir Tabakovic, Xueyan Liu, Damian Palin, Erik Schlangen Jan 2019

Optimization Of The Calcium Alginate Capsules For Self-Healing Asphalt, Shi Xu, Amir Tabakovic, Xueyan Liu, Damian Palin, Erik Schlangen

Articles

Featured Application: This self-healing technology for asphalt pavements has the potential to greatly disrupt asphalt production methods (which have been stable over the past 100 years).This paper presents a development process of ‘calcium-alginate microcapsules encapsulating an asphalt bitumen rejuvenator’. The encapsulated rejuvenator is released when required (on demand) which rejuvenates the aged binder. Once crack is initiated and starts propagating it encounters a microcapsule, energy at tip of the crack opens the microcapsule, releasing the rejuvenator (healing agent). The rejuvenator will infuse into the aged binder soften it, allowing to flow, two broken edges to get into a contact and …