Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"Aggregate Particles"”.
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Advanced image analysis and techniques for degradation characterization of aggregates
… or shape properties of virgin and recycled aggregate sources are known to affect pavement and railroad track mechanistic behavior and performance significantly in terms of strength, modulus and permanent deformation. Under repeated traffic loading aggregate particles used in construction of …
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Discrete element modeling of railroad ballast using imaging based aggregate morphology characterization
… and load distribution. In general, ballast aggregates are considered as uniformly graded, angular shaped with crushed faces. However, various ballast aggregate gradations and particle shapes are in use yet their effects on ballast performances remain unknown. In previous designs and modeling …
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Contractor Variability in Construction of Cement Treated Base Layers
… (RAP) content; cement content; amounts of aggregate particles finer than the No. 8, No. 50, and No. 200 sieves; 7-day moisture content, and 28-day moisture content. The significant predictors of the same response variables on US-91 were in-situ moisture content, cement content, amount of …
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Floc density measurement and the effects of microproperty variations on sludge dewatering characteristics
… as having a three-tiered structure: (1) primary particles, (2) floc particles, and (3) aggregate particles. To investigate sludge structure in relation to sludge dewatering, this study has defined sludge structure using several sludge particle micro properties. A laboratory technique …
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Development of a short test for the identification of aggregates causing poor concrete performance when frozen
… and economical method to separate bad from good aggregates which will undergo the freezing and thawing of natural weather conditions after incorporation in concrete. Freeze-thaw teats of air-entrained concrete specimens, teats on curing period of air-entrained concrete specimens exposed to …
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Mix design and testing improvements for 3D printable concrete mixtures with fibers
… mixes, focused around paste thickness on aggregate particles. Printability of a mix was measured by overall mix shear, using a custom-designed head for a pocket vane shear test. Finally, the authors created a baseline printable mix and tested increasing fiber dosages, maintaining paste …
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Detailed population balance modelling of industrial titania synthesis
… for simulating aerosol synthesis of structured particles using a stochastic method. This is developed in the context of the industrial titania (TiO2) process to enable extensive numerical characterisation of the pigmentary product. A reactor network model is used to provide a modular treatment …
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Machine learning techniques for identifying railroad ballast degradation
… ballast is a layer of uniform sized crushed aggregate particles placed between, below and around the crossties. Railroad ballast transfers the load from crossties to the subgrade layer, provides lateral track stability and facilitates the drainage of water. Repeated traffic loading and …
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Asphalt Oxidation Kinetics and Pavement Oxidation Modeling
… in the model such as the effect of small aggregate particles on oxygen diffusion. Carbonyl area and viscosity of binders recovered from field cores of three pavements in Texas were measured and were used for model calibration and validation. Results demonstrated that the proposed model …
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Detailed Population Balance Modelling of Titanium Dioxide Nanoparticle Synthesis
… the aerosol synthesis of titanium dioxide nanoparticles. It begins by exploring whether the morphological data captured by an existing detailed particle model can be used in a milling model to relate particle morphology and ultimately the particle synthesis conditions to the behaviour of …
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Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior
Ballast, typically comprising large sized aggregate particles with uniform gradation, is an essential layer in the railroad track substructure. Functions of ballast include facilitating load distribution and drainage, maintaining track geometry and track stability, and providing track resilience …
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Concrete microstructure homogenization technique with application to model concrete serviceability
… in which concrete is regarded as cement and aggregate particles connected by interfacial transition zone (ITZ). Defined on a representative volume element (RVE), the relationship between microstructure and macro properties is established. The proposed model is validated by experimental …
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Analyses and modeling of track transition site responses from instrumented bridge approaches
… movements. In addition, using the polyhedral particles in the BLOKS3D DEM program, numerical simulations were conducted to study the micromechanical interactions of smaller sized ballast aggregate particles used in the stone blowing remedial measure, which essentially fill any tie-ballast gap …
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Composition and microstructure of concrete mixtures subjected to biogenic acid corrosion and their role in corrosion prediction of concrete outfall sewers
… and spalling of the adjacent concrete and aggregate particles. In addition, the calcium sulphate precipitates as gypsum which reacts with various aluminates to form secondary ettringite. These mechanisms lead to the loss of stiffness and strength, accompanied by expansion and cracking, and …
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The microstructure of synthetic aggregate produced from waste materials and its influence on the properties of concrete
… the properties and microstructure of synthetic aggregate produced using granite quarry fine waste blended with low grade ball clay as the binder. The investigation involved the use of various engineering tests and microstructural characterization techniques with special attention on the …
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Development of a New High Performance Cold Mix Asphalt
… solution was used as a replacement for the aggregate pre-wetting water in the CBEM. CCR played a vital role activating the SSFA by breaking the glassy phases of the non-amorphous silica in the SSFA, while the waste calcium hydroxide solution increased the hydraulic reactivity of the …
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Fourier Transform Interferometry for 3D Mapping of Rough and Discontinuous Surfaces
… seen in applications requiring imaging of rock particles, present a unique set of obstacles that cannot be overcome using existing FTI techniques. This work is based on an original analysis of the limitations of FTI and the means in which errors are generated by the particular features …
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Biocementation of Road Foundations: Element Testing, Physical Modelling, and Micro-Scale Characterisation
… to improve road foundations. A crushed granite aggregate, representative of typical granular materials used in road foundations, was consistently used throughout the experimental work. Chemical analyses and permeability measurements monitored the progression of MICP during treatment. The …