Digital Commons Network^™

Biological Seawater Desalination Using Green Algae And Cyanobacteria, Abdul Mannan Zafar

Dissertations

Water shortage in many coastal parts of the world is reaching alarming situation, including the United Arab Emirates. Urbanization and rapid population growth are generating critical water demands with an increase in per capita consumption. Seawater is usually treated by membrane processes such as Reverse Osmosis (RO). However, this technology is energy intensive and generates excessive brine as a waste. The solution to this problem can be found in natural remediation techniques that can reduce salt concentration from seawater, such as halophytes. A salt-tolerant species can consume Na⁺ and Cl^- ions and increase cellular growth which is termed …

Characterization And Structural Shear Behavior Of Recycled Aggregate Concrete Beams Reinforced With Basalt Fibers And Basalt Bars, Shahrukh Shoaib Ul Haq

Dissertations

Recycling construction waste material offers a sustainable solution to the problem of disposing of concrete construction and demolition waste. The use of basalt fibers (BF) and basalt fiber-reinforced polymer (BFRP) reinforcing bars in concrete structures made of recycled concrete aggregate (RCA) would prolong their service life and reduce the maintenance cost. This research aims to investigate the potential use of BF, RCA, and BFRP reinforcing bars to produce sustainable and steel-free structural concrete. The study consisted of material characterization testing, numerical simulation, and large-scale beam testing.
Material characterization tests were performed on normal-strength concrete (NSC) and high-strength concrete (HSC). The …

Numerical Simulation Of Concrete Beams With Discontinuity Regions Reinforced With Nonmetallic Reinforcing Bars, Amena Mohammad Ousama

Theses

Nonmetallic Glass Fiber-Reinforced Polymer (GFRP) reinforcing bars are considered a viable alternative to the conventional steel reinforcement because of their high strength-to-weight ratio and noncorrosive nature. This research aimed to investigate the nonlinear structural behavior of GFRP-reinforced concrete beams with discontinuity regions (D-regions) through numerical analysis. Three-dimensional (3D) numerical models were developed to simulate the nonlinear structural behavior of GFRP-reinforced deep beams with and without web openings. The models adopted realistic constitutive laws that accounted for the nonlinear behavior of the materials used. Predictions of the numerical models were validated against published experimental data. A parametric study was conducted to …

A Comprehensive Evaluation Of Satellite-Based Precipitation Products And Their Performance In Arid And Temperate Climates, Mohammed Tarig Mahmoud

Dissertations

Accurate and continuous precipitation monitoring is critical to enable effective water resources management; the challenge arises from the spatial and temporal variability of precipitation. The recently launched Global Precipitation Measurement (GPM) satellite has the capability to detect and measure all types of precipitation using advanced instruments. Being at its early stages of development, the products of the GPM IMERG (early, late, and final-run-products) need to be validated using multiple spatial and temporal assessment techniques. Several studies have emerged over the past few years evaluating GPM IMERG results over areas of limited size. These areas were set by hydrologic interest (e.g., …

Sludge-Based Activated Carbon: Characterization And Performance For Removal Of Methylene Blue From Aqueous Solution, Ahmad Anwar Al Madhoon

Theses

Domestic wastewater treatment plants in the United Arab Emirates (UAE) produce 122 thousand tons of dried sludge annually. About 70% of this sludge is dumped in landfills, creating water and soil contamination. Sludge is an energy-rich organic material that could be converted into activated carbon by thermal or chemical processes. Potassium hydroxide has shown great potential as an activating agent for producing high-quality sludge based activated carbon (SBAC). However, its use adds to the cost of the production process. Thus, there is a need for an alternative activating agent that is not costly. One possible chemical is carbide lime which …

Performance Evaluation Of Glass-Fiber Reinforced Cement-Free Geopolymer Concrete, Mohammad Zuaiter

Theses

The alkali-activation of aluminosilicate materials produces a geopolymer binder that promises to be a sustainable replacement to cement in concrete. Yet, such concrete has experienced brittle behavior and poor resistance to cracking. As a means of improving its performance, this research assesses the feasibility of utilizing glass fibers in slag-fly ash blended geopolymer concrete for structural applications. A blend of slag and fly ash served as the binding material. Two types of glass fibers were used individually or as a hybrid combination. Type A and B glass fibers had similar properties but different lengths of 24 and 43 mm, respectively. …

Using Metal-Organic Frameworks (Mof) To Reduce The Carbon Footprint Of Concrete, Mona Ibrahim El-Hallak

Theses

The production of concrete by the construction industry has a massive impact on the environment. The process of manufacturing its main component, cement, releases a considerable amount of anthropogenic carbon dioxide. This thesis is concerned with the production of sustainable and eco-friendly concrete that integrates metal-organic frameworks (MOF) to capture and offset the CO₂ emissions emitted during the production of cement. The main objective is to synthesize a MOF capable of capturing CO₂ in concrete through accelerated carbonation curing and to assess its impact on concrete performance. Different parameters were examined, including the MOF content, initial curing duration, …

Numerical Modelling Of Externally-Bonded Fiber Reinforced Polymer Shear-Strengthened Reinforced Concrete Beams Subjected To Fatigue Loading, Nagwa Ibrahim Fares

Theses

An extensive number of existing structures persistently exposed to fatigue loading such as bridges, offshore structures, pavements, and highways, are in urgent need of repairing and strengthening. This may be attributed to the continuous increase in the load requirements, change of the structure’s function, and meeting current load standards. Among the potential methods of rehabilitation and strengthening of existing reinforced concrete structures, the externally bonding fiber reinforced polymers (FRP) composites are gaining massive popularity and becoming a viable and cost-effective method. Shear failure of reinforced concrete (RC) beams is known to be brittle, which occurs without prior sufficient warnings; therefore, …

Behavior Of Steel Fiber Reinforced Concrete Made With Recycled Concrete Aggregates: Material Characterization And Deep Beam Shear Response, Nancy Kachouh

Dissertations

This research aims to examine the performance of concrete made with recycled concrete aggregates (RCAs) and steel fibers. It comprises material characterization tests, large-scale reinforced concrete (RC) deep beam tests, and numerical modeling. Material characterization test parameters included the RCA replacement percentage (30, 70, and 100%) and the steel fiber volume fraction (vf = 1, 2, and 3%). Fourteen large-scale deep beam numerical models with and without web openings made with 100% RCAs and steel fibers were developed and validated through a comparative analysis with test results. A numerical parametric study was conducted to investigate the effect of varying …

Performance Assessment Of Existing Rc Bridges Equipped With Seismic Risk Mitigation Systems, Homam Mohamad Ghazal

Theses

Many bridges built before adopting current design standards may be at risk as they do not meet the latest seismic performance objectives. Bridges are vital infrastructure components required to be serviceable after earthquakes to avoid negative consequences on daily traffic. Previous seismic hazard studies considered the United Arab Emirates an earthquake-prone region subjected to two scenarios: (i) near-field events, and (ii) far-field earthquakes. Therefore, the vulnerability of pre-seismic code bridges in the UAE should be carefully assessed, and retrofit techniques should be proposed to mitigate possible earthquake losses. This study is thus devoted to assessing the seismic vulnerability of a …

The Impact Of Wastewater Chemistry And Flow Characteristics On Hydrogen Sulfide Concentration, Mohsina Muhammed Sherief

Theses

Hydrogen sulfide (H₂S) is a naturally occurring, highly toxic gas that is formed from the decomposition of sulfur compounds. At low concentrations, H₂S is an irritant for the eyes, respiratory and gastrointestinal tract. At higher H₂S concentrations, it produces neurological impairment with dizziness, headache, and loss of consciousness. Mortality was reported to reach 6 percent following exposure to elevated concentrations. H₂S is generated in different industrial processes. In wastewater collection and treatment plants, H₂S is a common source of concrete and metal corrosion that has resulted in huge economic loss. …

Strengthening Of Concrete Deep Beams Using Carbon Fabric Reinforced Cementitious/Geopolymeric Matrix, Nour Mohamed Muhsen Khir Allah

Theses

This research aimed to examine the effectiveness of using carbon fabric-reinforced matrix (C-FRM) composites to improve the shear response of reinforced concrete (RC) deep beams. Ten RC deep beams with a/h of 1.6 were tested, where a is the shear span and his is the beam depth. Test parameters included the presence of internal shear reinforcement (no shear reinforcement and minimum shear reinforcement), number of C-FRM composite layers (one and two layers), angle of inclination of the second layer of CFRM (90o and 0o with respect to the longitudinal direction of the beam), and type of matrix (cementitious and geopolymer). …

Environmental Assessment Of The Impact Of Land-Based Discharges On Marine Water And Sediment Quality In Dubai, Uae, Ayman Fathy Halawa

Theses

The current seawater and Creek – Canal waterway in the Emirate of Dubai, UAE, is under tremendous pressure because of continuous urban water discharges from land-based sources. Therefore, the impact of urban water discharges on marine water and sediment quality in the Emirate requires a thorough assessment. The main objective of this study is to assess the impacts of effluent discharges on the quality of water and sediment in the open sea and Dubai Creek. The land-based sources include the power and desalination plants, industrial sector, sewage treatment plant, and stormwater runoff. To achieve the stated objective, relevant data on …

Comprehensive Characterization Of The Aerosol And Cloud Condensation Nuclei In The Uae, Farah Hassan Abdi

Theses

Cloud seeding has emerged as a significant alternative freshwater source in the United Arab Emirates (UAE). It is employed to manipulate weather conditions and increase precipitation in specific target regions. These efforts aim to densify clouds and enhance the likelihood of rainfall by inducing nucleation. This technique involves an operational crew aboard an aircraft that disperses substantial quantities of seeding particles, such as salts or silver iodide, into suitable clouds. These particles can serve as cloud condensation nuclei (CCN) and indirectly affect the rate of rainfall. In 2018, cloud seeding operations were responsible for approximately 10-15% of the UAE's total …

Performance Of Ultrasound-Assisted Forward Osmosis Membrane Process In Desalination Of Seawater, Bara Awwad Al-Sakaji

Theses

The objective of this study was to investigate the effect of using ultrasound on water flux through forward osmosis membrane when applied for seawater desalination. A synthetically prepared solution simulating seawater characteristics was used. Parameters considered in the investigation included membrane cross-flow velocity (0.25 and 1.0 cm/s), flow configuration (co-current versus counter-current), direction of ultrasound waves relative to the membrane side (active layer versus support layer), and type of draw solution (NaCl versus MgCl₂). Furthermore, a two-level factorial design was considered in the analysis of the results obtained from the experimental work. This study revealed that applying a …

Performance Evaluation Of Cement-Free Geopolymer Concrete Made With Recycled Concrete Aggregates And Steel Fibers, Jamal Ahmad Samer Medljy

Theses

Sustainable and innovative alternatives have been investigated to replace concrete’s main components, natural aggregates, and cement. Previous studies have been carried out to replace NA and cement with recycled concrete aggregates (RCA) and inorganic alkali-activated geopolymer binders, respectively. Yet, such sustainable concrete has only been proposed for non-structural purposes, owing to the inferior properties of RCA. This research work aims to assess the feasibility of reutilizing RCA from construction and demolition waste and locally available industrial solid by-products in the production of sustainable geopolymer concrete for structural applications. The binding materials were either in the form of a single precursor, …

Behavior Of Steel Fiber-Reinforced Geopolymer Concrete Made With Recycled Concrete Aggregates, Abdalla Ahmed Moallim Hussein

Theses

Industrial by-products and recycled concrete aggregates (RCA) have the potential to fully replace cement and natural aggregates, respectively, in the production of concrete rather than being discarded wastefully into landfills or stockpiles. Yet, their combined use in the development of a novel RCA geopolymer concrete has been limited to nonstructural purposes, owing to the inferior mechanical and durability properties of said concrete. To improve the properties of geopolymer concrete made with RCA, steel fibers may be added to the mix. This research aims to study the feasibility of reutilizing locally available industrial solid wastes and RCA in geopolymer concrete for …

Performance Of Cement-Free Geopolymer Concrete Made With Ceramic Waste Powder Using Taguchi Method, Ponalagappan Chokkalingam

Theses

The ceramic industry produces a substantial amount of waste during its production processes. Recycling and reutilizing such ceramic waste is a challenge due to its extended biodegradation period. Consequently, the ceramic industry is dedicated to attaining a sustainable solution to dispose of this waste rather than discarding it wastefully into landfills or stockpiles. In turn, the demand for ordinary Portland cement has been on a steady increase, leading to concerns about the sustainability of the construction industry. As a sustainable alternative to cement, alkali-activated binders have been proposed owing to their ability to reduce carbon emissions, preserve nonrenewable natural resources, …

Assessment Of The Roadside Design And Safety Status In The Emirate Of Abu Dhabi, Dina Mustafa Muhammad Awadalla

Civil and Environmental Theses

Single-vehicle, run-off-road (SVROR) crashes account for a significant portion of all road-related injuries and fatalities worldwide. However, no previous study has neither examined to what extent roadside design guidelines have been applied, nor (and most importantly) investigated whether having a compliant roadside design has a positive impact on reducing the likelihood of fatal injuries. Thus, the objectives of this research are i) to examine the level of roadside design compliance within the studied area based on the selected benchmark and ii) to investigate whether roadside design compliance has a positive impact on reducing the likelihood of fatal injuries in SVROR …

Bond Behavior Of Fabric Reinforced Geopolymeric Matrix-Concrete Joints, Feras Farid Abu Obaida

Civil and Environmental Theses

This research aimed to examine the potential use of a geopolymeric matrix as a sustainable alternative to commercial mortars in carbon fabric-reinforced matrix composites. Single-lap shear tests were conducted to examine the bond behavior at the fabric-matrix interface. Test parameters included the type of matrix (geopolymeric and cementitious matrices), the type of fabric (unidirectional and bidirectional) and the bonded length (50 to 300 mm). The geopolymeric matrix was a blend of fly ash/ground granulated blast furnace slag activated by an alkaline solution of sodium silicate and sodium hydroxide. The bond behavior of the geopolymeric-matrix specimens was characterized and compared to …

The Effect Of Climate Change On Groundwater Recharge In The United Arab Emirates, Yuliya Fadlallah Saade

Civil and Environmental Theses

Climate change is impacting ecosystems and the water resources by causing temperature variation. Evapotranspiration rates are increasing when the temperature is high whereas, precipitation amount and intensity are varying based on geographical locations.

This change in precipitation has an inevitable impact on the groundwater recharge. Quantification of groundwater recharge is a prerequisite for efficient and sustainable groundwater resources management in arid regions.

Although, both surface and groundwater resources in the United Arab Emirates (UAE) are scarce; the anticipated climate change impacts could make these resources even scarcer. As such, the main aim of this thesis is to assess the potential …

Assessment Of Different Seismic Retrofit Systems Of Rc Buildings For Earthquake Risk Mitigation, Aya Ragab Mohamed Abou Ei-Hamd

Theses

Many existing Reinforced Concrete (RC) structures were designed and constructed at a time when design codes were insufficient according to current standards. This class of structures is at risk of damage when subjected to strong earthquake loading. Therefore, several seismic retrofit techniques have been investigated experimentally to increase the earthquake resistance and damage-control potential of pre-seismic code structures using different methods such as quasi-static and pseudo-dynamic testing. However, a limited number of studies have focused on investigating the overall seismic performance of retrofitted RC structures using shake table testing. The first task of this study assesses analytically and experimentally the …

Development Of A Composite Sustainability Index For Roadway Intersecttion Design Alternatives In The Uae, Maryam Juma Al-Kaabi

Theses

Many studies had been carried out to evaluate the sustainability of transportation systems, but little attention was given in these studies to the design of roadway intersections. The objective of this study was to define a framework to assess intersection sustainability from a road-user perspective and to develop a visual tool that helps decision-makers to support a more sustainable design of roadway intersections. Suitable sustainability indicators that would serve as elements in the built framework at the strategic and early planning level were extracted from the literature. The extracted indicators were utilized with relative weights to develop basic dimensional indices …

Strengthening Of Concrete Deep Beams With Extreme Discontinuities Using Near-Surface Mounted Composites, Moustafa Seifeddin Mansour

Civil and Environmental Theses

Installation of a web opening that fully interrupts the natural load path in concrete deep beams produces regions of extreme discontinuities and reduces the shear strength. This research examined the effectiveness of using near-surface-mounted carbon fiber-reinforced polymer (NSM-CFRP) reinforcement to restore the shear strength of deep beams with extreme discontinuities. The strut-and-tie model (STM) procedures were utilized to develop three different strengthening solutions around the discontinuity regions. A total of eight deep beam specimens (150 x 500 x2700 mm) with a shear span-to-depth ratio of a/h = 0.8 were constructed and tested. One beam was solid. Seven beams had a …

Assessment Of Carbon Emissions Of Road Projects And Development Of A Framework For Carbon Footprint Calculation Of Roads In The City Of Abu Dhabi, Mohammed H. H. Alzard

Civil and Environmental Theses

Climate change has become a global issue affecting the environment and human health. Transportation is a major contributor of greenhouse gases (GHG) emissions, with road transport being responsible for more than half of these emissions. The main objective of this thesis was to estimate the carbon footprint associated with road projects in the city of Abu Dhabi following a comprehensive approach that considers all activities within the life cycle of roads. Three cases were considered including, Al Rahba City internal road network, the upgrading of Al Salam Street, and the widening of the Eastern Corniche Road. A carbon footprint estimation …

Performance Prediction Of Concrete Deep Beams Containing Cutouts Internally- Reinforced With Composite Bars, Somoud Jebril Arabasi

Theses

The development of code provisions for the use of strut-and-tie model (STM) in structural design has been hindered by great uncertainties due to the lack of experimental evidences. The problem becomes more complex when the conventional steel reinforcing bars around disturbed regions are replaced by non-metallic composite reinforcement. This research aimed to investigate the structural behavior of concrete deep beams with cutouts internally reinforced with glass fiber-reinforced polymer (GFRP) bars around regions of discontinuities. Different STMs were developed for the design of GFRP-reinforced concrete deep beams. The models were analyzed through the use of ACI 318 (2014) and CSA S806 …

Combining Non-Destructive Tests To Improve The Reliability Of Evaluating Concrete Quality, Afra Al Asri Mohammed Obaid Al Dhaheri

Civil and Environmental Theses

Non-destructive tests (NDT) are commonly used in construction to evaluate concrete quality for both existing structures and during construction. The reliability of these tests have been questioned. This thesis is concerned with evaluating concrete strength and durability using different non-destructive tests (NDT). Also, it focuses on applying different combination of NDT to predict the concrete strength and durability using regression models. The main objective of the study was to investigate how to improve the reliability of nondestructive tests NDT to evaluate the concrete quality by combining more than one NDT test for concrete mixtures commonly used in Al Ain city, …

Calibrating And Evaluating Dynamic Rule-Based Transit-Signal-Priority Control Systems In Urban Traffic Networks, Md Didarul Alam

Civil and Environmental Engineering Dissertations

Setting the traffic controller parameters to perform effectively in real-time is a challenging task, and it entails setting several parameters to best suit some predicted traffic conditions. This study presents the framework and method that entail the application of the Response Surface Methodology (RSM) to calibrate the parameters of any control system incorporating advanced traffic management strategies (e.g., the complex integrated traffic control system developed by Ahmed and Hawas). The integrated system is a rule-based heuristic controller that reacts to specific triggering conditions, such as identification of priority transit vehicle, downstream signal congestion, and incidents by penalizing the predefined objective …

A Hierarchical Modelling Approach For Assessing The Impact Factors Of The Measured Of Mobility And Safety At Intersections, Hiba Eyesha Abou-Kassem

Civil and Environmental Theses

Measuring safety and mobility for various types of intersections is crucial in any transportation study. Many factors contribute to changing the effectiveness of the different types of intersections on mobility and safety. Deciding which type of intersection is most suitable in a particular environ and prevailing traffic conditions depends on the number of crashes, injuries, delay time, etc. This study focuses on two intersection types; signalized intersections and non-signalized intersections (only roundabouts). The aim of this research is to devise a theoretical modeling framework and hence a statistical-based methodology that can be used to assess the safety and mobility measures …

Durability Of Glass Fiber-Reinforced Polymer Bars In Seawater-Contaminated Concrete, Abdelrahman A. E. Alsallamin

Theses

This research aims to investigate the durability performance and microstructure characteristics of two different types of glass fiber-reinforced polymer (GFRP) bars in severe environment. GFRP bars encased in seawater-contaminated concrete were immersed in tap water for 5, 10, and 15 months at temperatures of 20, 40, and 60°C. Half of the specimens were conditioned under a sustained load of 25% of their ultimate strength whereas the other half was conditioned without load. Following conditioning, the GFRP bars were retrieved then tested to failure under uniaxial tension. Microstructure analysis was performed by employing differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) …