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Full-Text Articles in Engineering
Investigation Into Mitigation Of Alkali-Silica Reaction Using Selected Scms In Presence Of Potassium Acetate Deicer, Jigar Desai
Investigation Into Mitigation Of Alkali-Silica Reaction Using Selected Scms In Presence Of Potassium Acetate Deicer, Jigar Desai
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Alkali-silica reaction (ASR) is one of the most recognized durability problems in concrete leading to premature deterioration of different types of concrete structures. Recent investigation into premature deterioration of airfield concrete pavements indicated the aggressive effects of alkali-acetate and alkali-formate based deicers on concrete containing marginal aggregates, in particular on their potential to induce ASR.. This dissertation presents the results and analysis from a research study conducted to evaluate the effectiveness of selected supplementary cementitious materials-SCMs (fly ash and slag) as ASR mitigation measures in presence of potassium acetate based deicer.
Five aggregates that encompass a range of mineralogies and …
Sediment Transport Upstream Of Orifices, David Powell
Sediment Transport Upstream Of Orifices, David Powell
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Sediment transport upstream of orifices has not been studied outside the realm of the restoration of reservoir storage capacity. This experimental study used a large basin with a circular orifice outlet and a movable sand bed leveled with the invert of the orifice. Three sizes of non-cohesive, uniform sand were used with d50 values of 0.29mm, 0.72mm, and 0.89mm. Bed profiles at equilibrium scour conditions were measured for three different head levels for each sediment size. The maximum scour depth, length, and scour width were related to the particle size and the available head. The longitudinal and lateral extents …
Wind Effects On Monosloped And Sawtooth Roofs, Bo Cui
Wind Effects On Monosloped And Sawtooth Roofs, Bo Cui
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Wind is one of the significant forces of nature that must be considered in the design of buildings. The actual behavior of wind is influenced not only by the surface (or boundary-layer) conditions, but also by the geometry of the building. All sorts of turbulent effects occur, especially at building corners, edges, roof eaves. Some of these effects are accounted for by the wind pressure coefficient. Wind pressure coefficients used in practice have usually been obtained from experimentally by testing models of different type of structures in wind tunnels.
In this study, a series of wind tunnel tests with scale …
Evaluation Of Lithium Based Deicing Chemicals For Mitigating Asr In Concrete Pavement, Senthil Soundarapandian
Evaluation Of Lithium Based Deicing Chemicals For Mitigating Asr In Concrete Pavement, Senthil Soundarapandian
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Deicing and anti-icing chemicals such as alkali-acetate and alkali-formate based formulations are increasingly being used on airfield pavements. Among these new deicers, potassium acetate-based formulations are widely used due to their environmentally friendly nature and effectiveness in melting and undercutting ice at low temperatures. Recent research on premature deterioration of airfield pavements due to alkali-silica reaction (ASR) has indicated that alkali-acetate and alkali-formate deicers such as potassium acetate and sodium formate may have been responsible for the observed distress. In an effort to develop a deicing chemical that is benign to concrete from an ASR standpoint, a new deicing formulation …
Characterization Of Recycled Aged Crm Binders, Soon-Jae Lee
Characterization Of Recycled Aged Crm Binders, Soon-Jae Lee
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The incorporation of conventional reclaimed asphalt pavement (RAP) in hot-mix asphalt (HMA) pavements has become routine in many states around the United States and many other countries all over the world. In addition, the recycling of crumb rubber modified (CRM) materials has been an area of interest since CRM was first used in asphalt paving materials over 40 years ago. Previous research on the recycling of rubberized asphalt concrete (RAC) materials have been limited and focused mainly on the mixture properties at the location of in-field paving. However, for the long-term performance characterizations, it is needed to investigate the aging …
Numerical And Physical Modeling Of Turbulent Shear Flows, John Raiford
Numerical And Physical Modeling Of Turbulent Shear Flows, John Raiford
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This dissertation is an evaluation of popular turbulence schemes; both three dimensional and depth-averaged, and also includes an experimental study on shallow near bed jets. The three dimensional and RNG turbulent closure schemes are evaluated for free and bounded shear flows. For free shear flows (circular and plane turbulent jets), the scheme with standard coefficient performs equally well and in some cases better than the renormalized group scheme in predicting growth rate, decay of centerline velocity and longitudinal velocity profiles. For turbulent kinetic energy across the jet, the inner region is better predicted by the RNG scheme.
The second case …
Evaluating The Impacts Of Accelerated Incident Clearance Tools And Strategies By Harnessing The Power Of Microscopic Traffic Simulation , Ryan Fries
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Traffic incidents cause Americans delay, waste fuel, cause injuries, and create toxic emissions. Transportation professionals have implemented a variety of tools to manage these impacts and researchers have studied their effectiveness, illustrating a wide range between different tools and locations. To improve this state of knowledge, this dissertation sought to 1) identify prominent and effective incident management strategies, 2) model six selected incident management strategies within five highway corridors in South Carolina, and 3) apply benefit-cost analysis to evaluate the impact of various combinations of these strategies.
To meet these objectives, the author evaluated published literature of the selected strategies, …
Wall And Ground Movements In A Braced Excavation In Clays And Serviceability Reliability Of Adjacent Buildings, Cheng Liang Hsiao
Wall And Ground Movements In A Braced Excavation In Clays And Serviceability Reliability Of Adjacent Buildings, Cheng Liang Hsiao
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The goal of this dissertation research is to establish an improved procedure for evaluating the excavation-induced ground settlement and building serviceability. This research covers several closely related topics. Firstly, a simplified small strain soil model developed by Hsieh et al. (2003), called the Modified Pseudo Plasticity (MPP) model, is evaluated for its capability and performance in the prediction of the excavation-induced ground deformation behavior using Finite Element Method (FEM). Secondly, for the development of the envisioned empirical models for estimating the excavation-induced wall and ground responses, a database of excavation case histories are compiled. To complement the database of excavation …
Information Flow To Support Front End Planning, Ryan George
Information Flow To Support Front End Planning, Ryan George
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Previous research has demonstrated the value of front end planning as it impacts project performance. This dissertation summarizes the findings of a research project which examined ways to improve information flow through the front end planning process. The front end planning process was carefully diagrammed as consisting of 33 distinct information flow activities, each with its own information flow entities and interactions. Fifty-one questionnaire survey forms were analyzed to obtain data for the 33 information flow activities that included activity duration, resources expended, and other supplemental insights such as the extent of information availability. The 51 projects were then grouped …