Civil and Environmental Engineering Commons^™

A New Fiber Reinforced Polymer Composite For Infrastructure Applications Using Recycled Carbon Fibers, Mojgan Maadandar

Civil Engineering ETDs

Abstract

Carbon fiber reinforced polymer (CFRP) composites have been attractive materials for many civil and mechanical applications. However, the high cost of carbon fibers has hindered its wide spread in many civil and structural applications. Furthermore, CFRP composites have been mostly disposed of in landfills after their end of service life, creating environmental concerns and potential release of toxic byproducts. A significant interest in recycling composites has appeared in the last decade for obtaining recycled carbon fiber. A process based on wet chemical degradation and thermal treatments of FRP composites showed the ability to produce recycled carbon fibers with 99% …

Viscoelastic Effects In Carbon Fiber Reinforced Polymer Strain Energy Deployable Composite Tape Springs, Elisa C. Borowski

Civil Engineering ETDs

Strain energy deployable composite structures are of great importance to the aerospace community due to their light weight, high stiffness, impressive flexibility, compact stowage configuration, and ability to self-deploy. These attributes make composite deployable hinges ideal for aerospace applications that can benefit from decreased payload and decreased structural complexity through a reduction in deployment parts. However, successful application of these deployable structures requires an in-depth understanding of their mechanical behavior throughout stowage and deployment processes. Upon release from a high strain stowage configuration, high deployment accelerations caused by a great amount of stored strain energy could potentially damage the structure …

Mechanical Characterization Of Polymer Concrete With Nanomaterials, Alaeddin Douba

Civil Engineering ETDs

Nanomaterials are defined by those whose characteristic length scale lies within the nanometer scale. Their extreme dimension achieves extraordinary mechanical properties superior to other micro and macro additives. The introduction of nanotechnology to Civil Engineering utilizes low volume inclusions of nanomaterials to alter the properties of conventionally used bulk materials. Polymer Concrete (PC) where epoxy polymer binders replace cement binders, has become a common repair material among many other application and often can be considered an alternative to Portland cement concrete (PCC). PC is often used in bridge deck overlays, manholes, machine foundations and repairs. Its diverse chemical composition and …

Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca

Civil Engineering ETDs

Cooling towers, integrated circuit (IC) manufacture and reverse osmosis (RO) generate copious amounts of wastewater high in colloidal and reactive silica inhibiting on-site or synergistic reuse. Silica present in cooling water can reach solubility limits via evaporation and form impervious scale on heat transfer surfaces that decreases efficiency. When water is treated by RO operating at high rejection, silica forms difficult-to-remove scale on the membrane feed side in the form of glassy patches and communities of aggregate particles, inhibiting aspirations for zero liquid discharge. Current methods for silica scale mitigation include abundant dosing with chemical antiscalents or complex operating schemes. …

Pavement Surface Distress Detection, Assessment, And Modeling Using Geospatial Techniques, Su Zhang

Civil Engineering ETDs

Roadway pavement surface distress information is essential for effective pavement asset management, and subsequently, transportation agencies at all levels dedicate a large amount of time and money to routinely collect data on pavement surface distress conditions as the core of their asset management programs. These data are used by these agencies to make maintenance and repair decisions. Current methods for pavement surface distress evaluation are time-consuming and expensive. Geospatial technologies provide new methods for evaluating pavement surface distress condition that can supplement or substitute for currently-adopted evaluation methods. However, few previous studies have explored the utility of geospatial technologies for …

Cost-Effective Monitoring Of Railroad Bridge Performance, Jose Alberto Gomez Romero Salazar

Civil Engineering ETDs

The railroad network carries 40 % of the freight in the US. Railroad bridges are the most critical part of the network and they need to be properly maintained for safety of operations. Railroad managers need to inspect the bridges in order to assess their structural condition. Railroad managers are interested in measuring displacements under train crossing events to prioritize their bridge management and safety decisions. However, bridge displacements are difficult to collect in the field, because they require a fixed reference from where to measure. Accelerations can be used to estimate dynamic displacements but to this date, the pseudo-static …

Hyporheic Nitrate Uptake And Stoichiometric Limitations: Mesocosm Experiments Along A River Continuum., Vanessa A. Garayburu Caruso

Civil Engineering ETDs

Nutrient uptake in streams and rivers is controlled by complex transport dynamics and biogeochemical interactions, which together regulate nutrient export from watersheds. Decoupling the relative contributions of transport and biogeochemical processes to nutrient uptake at the watershed scale has been challenging due to the spatial and temporal heterogeneity of physicochemical properties. Furthermore, logistical constraints have resulted in solute-specific analyses, primarily concentrated in headwater streams, that disregard the role of stoichiometry in controlling biological uptake. We used experimental mesocosm (column experiments) along the Jemez River-Rio Grande continuum (1^st-8^th stream order) to isolate spatial differences in biological nitrate uptake. …

Integrated Framework For Wildfire Risk Mitigation Planning At The Wildland/Urban Interface, Elmira Kalhor

Civil Engineering ETDs

Past suppression-based wildfire management practices have increased the frequency and intensity of wildfires. Advocates for the re-introduction of natural wildfire regimes must also prioritize wildfire damage protection, especially for vulnerable communities located near forests. Areas where urban and forest lands interdigitate are called the Wildland Urban Interfaces (WUIs). In the United States, the area of the WUIs is increasing, making more people vulnerable to wildfires. By responding to four research objectives, this dissertation proposed and tested an integrated framework for wildfire risk mitigation decision making at WUIs. Decision makers who could benefit from the results of this dissertation include WUI …

Reactor Design And Operation Variables To Improve Mixed Algal Biomass Productivity And Solids Separation: An Examination Of Operation Parameters, Density, And Settleability, Derek Jan Wichhart

Civil Engineering ETDs

Algae have been identified as a source of renewable, clean energy, with much research being devoted to identifying high energy yield algae, energy extraction methods, and reactor design with mono-cultures of algae, but little research has been done on reactor design and operational conditions with mixed cultures of algae to improve productivity and solids separation. The objective of this study was to determine if the settling characteristics of mixed algal cultures can be enriched or improved through manipulation of reactor design characteristics by incorporating cyclic settling or floating phases into operation, timing of light/dark cycles, and/or control of the solids …

Use Of Chemical And Isotopic Identifiers To Characterize Ground Water Contamination Near Two Uranium Mill Sites, Central Nm, Mitchell T. Schatz

Civil Engineering ETDs

Chemical and isotopic signatures were used to discriminate between anthropogenic ground water and naturally occurring constituents. The U-234/U-238 activity ratio (AR) was determined in 34 samples from several aquifers underlying two former uranium mills near Milan, NM. Disposal of uranium ore waste into unlined tailings resulted in ground water contamination in the Lower San Mateo Creek Basin area. Ground water contamination from uranium mills have impacted the local ground water for residents down-gradient from the mills.

Previous studies that used uranium isotopes identified activity ratios of mill-derived uranium were near the secular equilibrium of 1, and those from natural ground …

Study Of Vibration For Detection And Recognition Of Concealed Machinery Within Buildings, Sushil Ghimire

Civil Engineering ETDs

Recently international concern about nuclear proliferation has rapidly increased. Some governmental agencies have an interest in remotely detecting and recognizing concealed machinery within buildings to detect any anomalous activity occurring inside the building.

The vibration studies of the roof and the exhaust structures of an existing utility building, the Ford Utility Center at the University of New Mexico and a simplified laboratory structure representing an industrial building, called the doghouse are presented in this thesis. The vibration studies presented allow the reader to understand to what extent it is possible to identify machines concealed within a building.

To identify machines …

Practical Considerations In Determining Timber Pile Depth Using The Sonic Echo Method, Ali F. Jwary

Civil Engineering ETDs

The Federal Highway Administration indicates that about 85,000 bridges in the United States have no original contract documents with information about the type, depth, geometry and material of their foundations (FHWA, 2010). Furthermore, the National Bridge Inventory (NBI) provides information about 86,133 bridges nationwide that are rated as scour critical because of unknown foundation condition. In New Mexico, there are more than 281 bridges with unknown foundations, which are owned by the New Mexico Department of Transportation; 71 of these are timber bridges. These data indicate a serious problem that needs decisive action to assess the unknown bridge foundation characteristics …

Input Parameters In Discrete Element Modeling, Seyedali Yousefi

Civil Engineering ETDs

The discrete element method (DEM) is employed to study complex behaviors of particulate media. Input parameters may greatly affect the response of DEM models and should therefore be selected carefully. Scaling techniques are employed to enlarge prohibitively small time-steps. To study these techniques, dimensionless input parameters were defined. Responses of models in the dimensionless scale were invariant with choice of density, elastic modulus, and characteristic length if the dimensionless parameters were kept constant. Hence, density scaling is equivalent to use of a higher strain-rate, and stiffness scaling results in a higher strain-rate and an elevated stress state in the dimensionless …

Mix Design And Mechanical Characterization Of Stabilized Compressed Earth Blocks And Assemblies For The Jemez Pueblo In New Mexico, Nicole B. Trujillo

Civil Engineering ETDs

Earthen structures have a long architectural and cultural heritage in New Mexico. Similar structures are evident around the world. With the current depletion of natural resources and high cost of materials, compressed earth block construction offers a sustainable building material alternative. Stabilized compressed earth blocks (SCEB) are compressed earth blocks with additives such as, hydrated lime or Portland cement to protect the earth block from absorbing water. SCEBs are being produced using native soils for residential construction on the Jemez Pueblo in New Mexico.

The primary goal of this research is to enable production of SCEBs with native soils from …

High Performance Computing Applied To Structural Analysis Of Concrete Structures, Jose A. Mena Ortiz

Civil Engineering ETDs

Continuum mechanics models are the main tool in structural analysis. Due to

their continuity assumption, some of them do not predict accurately the behavior of

concrete structures. While these models are widely used by design engineers, many

are flawed for fundamental reasons.

The State-Based Peridynamic Lattice Model (SPLM) is presented in this thesis

as a viable alternative to continuum models. The SPLM is shown to have a simple

formulation that allows the engineer to fully understand the underlying theory. The

elastic, plastic and damage SPLM models are presented. Moreover, SPLM is shown

to be capable of modelling essential mechanisms in …

Groundwater Restoration Following In-Situ Leach Mining Of Uranium, Omar A. Ruiz Lopez

Civil Engineering ETDs

From 1950 to the early 1980’s New Mexico played an important role in the production of uranium (U) for the nuclear power industry and the nation’s weapon programs. Though the U mining and milling industry in New Mexico is inactive at present, increased interest in nuclear energy as a CO₂ free power source has led to proposals for renewed development of U resources. In particular, U mining projects have been proposed using both underground mining and in situ leach (ISL) mining. When feasible, ISL mining minimizes waste by eliminating; mine waste, mine dewatering, radiation exposure and the recovered U …

Understanding The Behavior Of Embankment Dams Under Blast Loading, Courtney L. Busch

Civil Engineering ETDs

This purpose of this study is to investigate the deformation-induced stability of earthen embankment dams to explosive airblast loading. This study specifically investigated the effects of close-in explosive airblast loads on the downstream toe of a homogeneous earthen embankment dam composed of cohesive soils. Small-scale explosive airblast experiments were performed on cohesive soils to obtain an experimental data set with which to compare numerical analyses. Experimental measurements included crater geometry, ground vibration energy, and air overpressure from the blast events. Laboratory tests were conducted on the experiment soils to obtain engineering properties including shear strength and compressibility indices. Finite element …

E. Coli Removal By Pleurotus Ostreatus Mycofilter In Simulated Wet Environmental Pond, Savannah E. Martinez

Civil Engineering ETDs

Stormwater runoff has been referred to as the water quality issue of the day. Contamination of surface waters is an environmental concern for both human and ecosystem health. In Albuquerque, New Mexico, it is a common practice to pond stormwater runoff before it is released into the Rio Grande. Ponding stormwater works as a best management practice (BMP) to help remove floatable debris and contaminants. Mycofiltration is a BMP that has recently been introduced into the stormwater quality community. Mycofiltration is the use of fungal mycelium as a natural mitigation approach to stormwater pollution. Mycofiltration has been proven to reduce …

Reconstructing The Historical Albuquerque Reach Of The Middle Rio Grande To Evaluate The Influence Of River Engineering On Floodplain Inundation, Jourdan Adair

Civil Engineering ETDs

Sustainable floodplain management is essential in achieving a balance between population growth and natural resource protection, especially in the face of climate change. While floodplain development in the Middle Rio Grande Valley has allowed for economic expansion in the region, it has come at a cost to the fragile ecosystem of the Southwest. In this study, the historical Albuquerque reach of the Middle Rio Grande is reconstructed, including floodplain topography, channel characteristics, and land cover from approximately 1918. The impacts of river engineering on flooding events are evaluated by comparing historic and current conditions. Hydrodynamic modeling is first used to …

Impacts Of Water And Saline Brine Flow On Fractured Wellbore Cement, Joshua Robert Ellison

Civil Engineering ETDs

Fractures in wellbore cements can develop and provide pathways allowing fluids such as hydrocarbons or brines to communicate with freshwater aquifers and/or reach the surface. Once formed, these fractures can be altered by the stresses acting on them as well as reactions with the fluids moving through them. Previous studies, mostly with acidic brines flowing through a fracture, have shown dissolution/precipitation reactions cause permeability to decrease and mechanical properties to change as the acidic brine creates reaction fronts slowly propagate through the face of the fractures. This study investigated fractured cement reacted with de-ionized water and saline brine under varying …

Characterization Of Consolidated Granular Salt, Melissa Marie Mills

Civil Engineering ETDs

Granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding the consolidation processes dependence on stress state, moisture availability, and temperature is important for demonstrating sealing functions and long-term repository performance. This study includes the characterization of laboratory-consolidated salt by means of microstructural observations, measurement of physical properties related to the pore structure, and quantification of pore sizes …

Investigation Of Interfacial Interaction Of Manganese Oxides With Organic Micropollutants, Mohamed Nabil Shaikh

Civil Engineering ETDs

Water reuse has become a necessary practice in arid and semi-arid regions like the Southwestern USA. However, a new generation of emerging organic micropollutants has been increasingly scrutinized in water sources. The aim of this study is to determine the changes in chemical composition occurring on the MnOx(s) surface after reaction with organic micropollutants using X-ray Photoelectron spectroscopy (XPS), Raman spectroscopy and solution chemistry analyses. Laboratory batch experiments were conducted to assess the reactivity of MnOx(s) with aniline, triclosan, phenol and bisphenol A. Analyses of XPS high resolution scans through the determination of the shape and position of Mn 3p …

Investigating Pedestrian Crash Risk In Albuquerque, New Mexico, Rahul Reddy Gade

Civil Engineering ETDs

Walking, being an important and basic form of transportation is crucial in everyday day life. Seen as an alternative to traditional modes of transport, walking is seen as an effective way to reduce dependence on fossil fuels and personal transport. Its health benefits and positive changes to the community are seen as incentives to promote walking as an effective mode of transport. As such, pedestrian safety is of utmost importance given the increase in pedestrian numbers and correspondingly, pedestrian crashes. The thesis studies pedestrian crash data and computes pedestrian crash rates for different intersections in Albuquerque, New Mexico. Crash rates …

Effects Of Alternative Traffic Input Levels On Interstate Pavement Performance In New Mexico, Md Amanul Hasan

Civil Engineering ETDs

Traffic is one of the key inputs in pavement design. The pavement Mechanistic-Empirical (ME) design allows three different types of input level of traffic data based on the availability of the data. They are: site specific data (Level 1), regional data (Level 2), and the national data (Level 3). Level 1 inputs (e.g., load magnitude, configuration, and frequency) are generated from Weigh-in-Motion (WIM) station installed in each site. However, it is not always practically possible to install WIM station due to high cost of WIMs. Therefore, often time the designers have to rely on the Level 2 or Level 3 …

Measurement Of Thermal Properties And Porosity Of Consolidated Salt., Laxmi Prasad Paneru

Civil Engineering ETDs

Salt formations may be used as repositories for long term isolation of nuclear waste. Excavating drifts in a subsurface salt formation produces granular salt spoils, which could be used as sealing material for boreholes and drifts. In drifts, the backfilled salt would conduct heat from the waste load to the host rock salt. The efficiency of heat dissipated from the backfill will depend on the thermal properties of the backfill. The results of this study show how these thermal properties evolve with the porosity of consolidating granular salt. Thermal properties and porosity of laboratory-consolidated salt and in situ partially consolidated …

Advancing The Food-Energy-Water Nexus: Closing Nutrient Loops In Arid River Corridors, Jacob Mortensen

Civil Engineering ETDs

Closing nutrient loops in terrestrial and aquatic ecosystems is integral to achieve resource security in the food-energy-water (FEW) nexus. Multiyear (2005-08), monthly samples of instream dissolved inorganic nutrient concentrations (NH4-N, NO3-N, soluble reactive phosphorus-SRP) along a ~300-km of the Rio Grande, NM, USA were used to investigate how the net source/sink behavior of wastewater and irrigated agriculture can be holistically managed to close nutrient loops. Wastewater on average contributed over 90% of the instream dissolved inorganic nutrients (101 kg/day NH4-N, 1097 kg/day NO3-N, 656 kg/day SRP). During growing seasons, the irrigation network downstream of wastewater outfalls retained on average 37% …

Analysis Of Brazilian Split Cylinder Using The State Based Peridynamic Lattice Model, Shreya Vemuganti

Civil Engineering ETDs

Concrete members deform discontinuously in the form of cracks and fracture. Continuum mechanics, which has dominated the field of solid mechanics over the years, does not handle such discontinuities. A material, as defined by continuum mechanics is that which is continuous and fills the space it occupies. Although this is a reasonable assumption for metals, it is an unrealistic notion for concrete. Stewart Silling invented peridynamics, which involves nonlocal solid modelling upon a continuous material space. Walter Gerstle developed a practical application of the peridynamic model for solid mechanics called the state-based peridynamic lattice model (SPLM). This approach involves material …

On Cross-Anisotropy Of Flexible Pavement Layer Materials For Improved Pavement Responses, Mesbah Ahmed

Civil Engineering ETDs

Pavement layer materials are typically assumed to be isotropic in determining pavement responses, such as stress and strain. The main benefit of the isotropic assumption is that stiffness defined by modulus of elasticity (E-value) is equal in all directions. In reality, stiffness along vertical and horizontal (i.e., and ) may vary due to density gradients in compacted layer materials caused by vertical compaction during construction. Therefore, pavement layer materials with different vertical and horizontal modulus (i.e., \u2260 ) are cross-anisotropic. Past studies have reported that degree of cross-anisotropy, ( ) ranges from 0.2 to 0.85 in Asphalt Concrete (AC) layers. …

Risk Assessment Of Post-Fire Floods On Dams And Their Floodplains, Krishna Chaitanya Jagadeesh Simma

Civil Engineering ETDs

The rapidly changing global climate and the increased dependence on infrastructure networks make our society vulnerable to natural disasters. Decision makers need to understand the intensity of potential natural disasters to take necessary actions to minimize their impacts. In Southwest United States, wildfires are increasing in frequency and magnitude. The literature review shows limited studies in evaluating the impacts of post-wildfire floods on civil infrastructures and residential zones. Earth dams are vulnerable to post-wildfire floods. The increased post-wildfire runoff volumes due to changes in soil characteristics and reduced vegetation could result in overtopping failure of an earth dam (dam-break scenario), …

A Study Of Asphalt Aging Behavior Using Molecular Dynamics Simulations, Jielin Pan

Civil Engineering ETDs

Oxidative aging is a major issue in asphalt pavements that leads to hardening of the asphalt, which further contributes significantly to asphalt pavement embrittlement and eventually results in excessive pavement cracking. In addition, the performance of asphalt binder is also highly related to its service conditions which involve climatic conditions and traffic conditions, such as temperature, moisture and traffic loads. Generally, the mechanical properties of asphalt before and after oxidative aging can be tested in the laboratory; however, the fundamental material science of asphalt before and after oxidative aging is difficult to be investigated in the laboratory regarding chemical composition …