Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Amino acids (1)
- Biomineralization (1)
- CFRTP (1)
- CNF (1)
- Carbonation (1)
-
- Cellulose Nanofibers (1)
- Cellulose Nanofibrils (1)
- Cement (1)
- Cement Hydration (1)
- Cement-Based Materials (1)
- Climate change (1)
- Compressive strength (1)
- Concrete (1)
- Creep (1)
- DMTA (1)
- Fiber-reinforced thermoplastic (1)
- Filler effect (1)
- Free shrinkage (1)
- High-speed shear mixer (1)
- Hygrothermal (1)
- Laboratory (1)
- Lake modeling (1)
- Land-use change (1)
- Linked models (1)
- Microstructure (1)
- Phosphorus (1)
- Pozzolanic (1)
- Rebar (1)
- Reinforced concrete (1)
- Rheology (1)
Articles 1 - 12 of 12
Full-Text Articles in Entire DC Network
Utilization Of Low-Lime Calcium Silicate In Hydrated And Carbonated Cementitious Materials, Mohammad Rakibul Islam Khan
Utilization Of Low-Lime Calcium Silicate In Hydrated And Carbonated Cementitious Materials, Mohammad Rakibul Islam Khan
Electronic Theses and Dissertations
This study investigated the potential application of wollastonite as a cementitious material in both hydrated and carbonated binder systems. Wollastonite is naturally occurring low-lime calcium silicate (CaO.SiO2) mineral with a substantially lower carbon footprint compared to the ordinary Portland cement (OPC). The first part of this work presented the application of wollastonite as partial replacement of OPC in traditional hydrated cement-concrete system. Second part of this work evaluated the properties of carbonation activated binder produced using wollastonite as the primary ingredient.
For the first part of the thesis, ground wollastonite with 3.5 µm and 9 µm mean particle …
An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour
An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour
Electronic Theses and Dissertations
Cellulose nanofibrils (CNFs) are hydrophilic biodegradable nanoparticles (typically, less than 0.2 mm in length and 20-50 nm in width) that can be extracted from various plants, trees, and recycled paper stock. Their low density, low toxicity, relatively low cost, high aspect ratio, and high specific surface enable functionalization. In this work, the effects of CNFs on selected properties of cement paste, mortar, and concrete were investigated. For the cement pastes, rheology tests using a simple rheometer showed a reduction in workability as CNF dosage increased. Free shrinkage tests showed an increase in shrinkage at high w/c ratios but a decrease …
A Laboratory Investigation Of Cement Based Materials With Cellulose Nanofibers, Parivash Takasi
A Laboratory Investigation Of Cement Based Materials With Cellulose Nanofibers, Parivash Takasi
Electronic Theses and Dissertations
Cellulose Nanofibers (CNFs) are used as additives in cement-based products to modify their properties. Recent studies about the effects of CNFs on cement paste showed inconsistent results for several different important properties, including compressive strength and free shrinkage. There is reason to believe that the unsystematic results of the compressive strengths were affected by the lack of uniform dispersion of CNFs. As a potential remedy, two different mixing methods were applied. The first method used a basic mixer, but aggregates were added to the cement paste mixture to improve the blending process. The second method utilized a high-speed shear mixer …
Development Of Finite Element Techniques To Simulate Concrete-Filled Fiber-Reinforced Polymer Tube Structures, Hakeem S. Majeed
Development Of Finite Element Techniques To Simulate Concrete-Filled Fiber-Reinforced Polymer Tube Structures, Hakeem S. Majeed
Electronic Theses and Dissertations
This dissertation presents the development of finite-element (FE) techniques to simulate the behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) in support of more effective structural design and analysis methods for buried composite arch bridges (BCABs) that use CFFT arches as main structural members. The research includes three specific topics to make contributions in different aspects of the investigation of these complex structures.
The first topic is the nonlinear three-dimensional FE modeling of steel-free CFFT splices. For model validation, comparisons were made between the model predictions and control beam and spliced beams with and without internal collars tested by …
Modeling Response Of Water Quality To Land-Use And Climate Change In Lake Auburn, Me, Nicholas Messina
Modeling Response Of Water Quality To Land-Use And Climate Change In Lake Auburn, Me, Nicholas Messina
Electronic Theses and Dissertations
Lake Auburn, Maine, USA, is a historically unproductive lake that has experienced multiple algal blooms since 2011. The lake is the water supply source for a population of ~60,000. We modeled past temperature, and concentrations of dissolved oxygen (DO) and phosphorus (P) in Lake Auburn by considering the watershed and internal contributions of P as well as atmospheric factors, and predicted the change in lake water quality in response to future climate and land-use changes. A stream hydrology and P-loading model (SimplyP) was used to generate input from two major tributaries into a lake model (MyLake) to simulate physical mixing, …
Development Of A Hybrid Thermoplastic Composite And Concrete Deck System, Benjamin T. Smith
Development Of A Hybrid Thermoplastic Composite And Concrete Deck System, Benjamin T. Smith
Electronic Theses and Dissertations
Reinforced concrete is a widely used structural system in conventional construction. It is used to create beams, columns, slabs, walls, bridge decks, dams, and many other structures. Concrete is a relatively inexpensive material that is much stronger in compression than in tension. This leads to the need to combine concrete with other materials to make an efficient hybrid structure. In conventional construction, steel reinforcing bars (rebar) are often used to carry the tension in the structure, as they are widely available and their design is well understood. There are some situations where rebar is not effective such as highly corrosive …
Potential Value-Added Utilization Of Wood Ash In Construction Materials, Naveen Saladi
Potential Value-Added Utilization Of Wood Ash In Construction Materials, Naveen Saladi
Electronic Theses and Dissertations
Wood ash is a byproduct from biomass power plants. Most of the wood ash is currently being disposed of as landfilling material that causes severe economic and environmental concerns. This project focuses on the feasibility of using this wood ash in construction materials. Wood ash was found to contain varieties of mineral phases including calcium carbonate, calcium aluminate, and quartz. Based on the chemical composition, the efficacy of wood ash (i) as supplementary cementitious materials (SCM), (ii) in the controlled low strength materials (CLSM) production and (iii) Portland cement production was evaluated.
Wood ash with adequate pozzolanic properties can be …
Investigating The Time-Dependent And The Mechanical Behavior Of Wood Plastic Composite Lumber Made From Thermally Modified Wood In The Use Of Marine Aquacultural Structures, Murtada A. Alrubaie
Investigating The Time-Dependent And The Mechanical Behavior Of Wood Plastic Composite Lumber Made From Thermally Modified Wood In The Use Of Marine Aquacultural Structures, Murtada A. Alrubaie
Electronic Theses and Dissertations
Wood Plastic Composite (WPC) lumber based on a patent-pending formulation is being explored for use in the manufacture of an aquaculture fish cage structure (Aquapod net pen cage), as an alternative to the current high density polyethylene (HDPE) lumber. The use of WPC lumber in structural applications in marine environments requires a comprehensive effort to understand the material viscoelastic behavior and the structural performance of the WPC lumber in marine environments where the WPC lumber is exposed to the combined effect of saltwater immersion and temperature (hygrothermal). The evaluation of the viscoelastic behavior of WPC lumber in marine environments was …
Tide And Storm Surge Dynamics In Estuaries Of Variable Morphology, Preston Spicer
Tide And Storm Surge Dynamics In Estuaries Of Variable Morphology, Preston Spicer
Electronic Theses and Dissertations
Storm surges are the most destructive component of coastal storms, and climate change is predicted to enhance the frequency of intense storm events in the future. Currently, most storm surge forecasting assumes linear surges and the extent to which this assumption leads to model inaccuracies is currently unknown. The goals of this research are to characterize storm surge in estuaries and determine the contribution of nonlinear tide-surge interaction to total inland surges. A citizen science experiment was conducted in four estuaries in Maine. Results show the estuary shape influences surges through convergence, friction and man-made constrictions. These mechanisms modified total …
Tidal And Subtidal Processes At The Mouth Of A Macrotidal Estuary, Rachel Chambers
Tidal And Subtidal Processes At The Mouth Of A Macrotidal Estuary, Rachel Chambers
Electronic Theses and Dissertations
Secondary flows and mixing have been shown to influence sediment transport, the vertical salinity gradient, and the exchange flow in estuaries. Typically, these hydrodynamic properties are investigated with respect to time and depth and their variability across the estuary is neglected. However, recent studies have shown that secondary flows and mixing, along with mechanisms that influence them, can exhibit lateral variability. Additionally, the variability of these hydrodynamic properties has not been studied in macrotidal estuaries, where the increased tidal forcing could affect the strength and cross channel variability.
There are two primary objectives of this thesis. The first objective is …
Perspectives On Water Resources Risk, Policy, And Stewardship, Anne Marie Lausier
Perspectives On Water Resources Risk, Policy, And Stewardship, Anne Marie Lausier
Electronic Theses and Dissertations
Water management approaches have historically optimized water for human use and placed lower emphasis on the relationship between ecosystems and humans. Despite efforts to balance human and ecosystem needs, existing management approaches tend to prioritize some needs, knowledges, and values over others. Natural and anthropogenic changes pose challenges to water governance institutions due to policy inflexibility, and may lead to ecosystem degradation, water stress, and conflict among water users. This work seeks to redress these shortcomings through three scholarly contributions. First, a conceptual framework for Water Resources Stewardship is developed in support of equitable and adaptive solutions under changing conditions. …
Process Optimization Of Levulinic Acid Production From Seaweeds And Its Upgrading To Tdo Oil, Maurvin Patel
Process Optimization Of Levulinic Acid Production From Seaweeds And Its Upgrading To Tdo Oil, Maurvin Patel
Electronic Theses and Dissertations
Levulinic acid (LA) is a platform chemical and it can be upgraded to various products like bio-oil. The acid hydrolysis of cellulose is a widely researched pathway to make LA. However, investments to produce LA commercially can be subjected to risks due to feedstock price volatility and high processing costs. Such risks can be reduced by expanding the feedstock portfolio to produce LA from feedstock beyond wood and improving the energy efficiency of the process. One little investigated feedstock for production of LA is macro algae (seaweed). Seaweed is potentially attractive because it has low content of lignin or 5 …