Recent Submissions

  • Conceptual design of a test bed for miner rescue

    Munny, Rowshon Ara Mannan; Hatfield, Michael; Wies, Richard; Bossert, Katrina (2019-08)
    In the mining industry, miners are constantly exposed to various safety and health hazards associated with often unpredictable conditions. When an accident occurs, it is difficult for the rescue team to come up with a proper plan for the rescue mission without having adequate knowledge of the situation. One possible approach to managing these hazards is to provide the rescue team with situational awareness such as real-time data regarding the environment (fire, poisonous or explosive gasses), as well as the location and physical condition of the trapped miners. Before starting the rescue mission, and in order to eliminate or reduce the dangers of exposing more humans to the explosive mining environment for information collection, a combination of unmanned ground vehicles (UGVs) and unmanned aerial vehicles (UAVs) is proposed. In this project, a conceptual test bed is designed to collect one specific set of information about a trapped miner (in this case, heartrate data). This test bed collects the required data from a heart rate sensor on the trapped miner and transmits it wirelessly to a nearby UAV which will receive the data and send it back to the rescue team via a UGV.
  • Toward computer generated folk music using recurrent neural networks

    Weeden, Rohan E.; Lawlor, Orion; Chappell, Glenn; Genetti, Jon (2019-05)
    In this paper, we compare the effectiveness of two different types of Recurrent Neural Networks, fully connected and Long Short Term Memory, for modeling music compositions. We compare both the categorical accuracies of these models as well as the quality of generated compositions, and find that the model based on Long Short Term Memory is more effective in both cases. We find that the fully connected model is not capable of generating non repeating note sequences longer than a few measures, and that the Long Short Term Memory model can do significantly better in some cases.
  • Passively encouraging offline networking in small, concentrated communities through UI/UX design

    Mitchell, Addeline; Metzgar, Jonathan; Lawlor, Orion; Chappell, Glenn (2019-05)
    The goal of this project is to identify whether it is possible to encourage users to communicate with one an other face-to-face through User Interface (UI) and User Experience (UX) design. It is well known that users can be maliciously manipulated by design elements and that concerns have been raised about the effects o f social media on interpersonal communication. The key is to find non-harmful means of guiding users to the desired action of speaking face-to-face with others. User testing for a custom web app was conducted for the purposes of this project. It is hoped that the results will provide developers with new consideration for UI and UX design.
  • Implementation of various bed load transport equations at monitoring sites along the Sagavanirktok River

    Laurio, Jenah C.; Toniolo, Horacio; Barnes, Dave; Stuefer, Svetlana (2019-05)
    In May 2015, the Sagavanirktok River in Alaska flooded, spilling over the Dalton Highway and destroying several sections of the road near the community of Deadhorse. The Alaska Department of Transportation and Public Facilities made repairs to the road and funded the University of Alaska Fairbanks, Water and Environmental Research Center (WERC), to conduct a multiyear study of hydro-sedimentological conditions on the Sagavanirktok River. Personnel from the WERC installed four monitoring stations for research purposes. The first monitoring station (DSS1) is located near Deadhorse at Milepost (MP) 405 of the Dalton Highway, the second (DSS2) is located below the Ivishak River (MP 368), the third (DSS3) is located in Happy Valley (MP 335), and the fourth (DSS4) is located at MP 318. Near each monitoring station, large pits were excavated to trap bed sediment as it moves downstream. Researchers involved in the Sagavanirktok River study have been collecting bathymetry measurements from the sediment pits since fall of 2015. The following document discusses a research project that focused on bed load transport along the Sagavanirktok River at monitoring sites DSS1, DSS2, and DSS3. Monitoring site DSS4 was not included in this study due to difficulties retrieving sediment data caused by high water levels. Sediment transport volumes measured from the test pits were compared with volume estimations calculated using Acronym (a computer program), and applying the bed load equations of Meyer-Peter and Muller, Wong and Parker, Ashida and Michue, Fernandez Luque and Van Beek, Engelund and Fredsoe, the Parker fit to Einstein’s relation, Lajeunesse et al., and Wilson, with a critical Shields value ( t #) of 0.06 and 0.03. The study results showed that in all cases the bed load transport volumes measured at sites DSS2 and DSS3 were far smaller than those calculated using the bed load transport equations. For monitoring site DSS1, a few of the bed load transport equations estimated volumes were close to those measured. The Acronym program was used only for sites DSS2 and DSS3 due to difficulties creating the grain size distribution curve at DSS1. Data show that the volumes calculated by Acronym are greater than those measured at both sites. The bed load transport equations used for the project were not applicable to the Sagavanirktok River.
  • Infrared video tracking of UAVs: Guided landing in the absence of GPS signals

    Graves, Logan W.; Hatfield, Michael C.; Lawlor, Orion; Raskovic, Dejan (2019-05)
    Unmanned Aerial Vehicles (UAVs) use Global Positioning System (GPS) signals to determine their position for automated flight. The GPS signals require an unobstructed view of the sky in order to obtain position information. When inside without a clear view of the sky, such as in a building or mine, other methods are necessary to obtain the relative position of the UAV. For obstacle avoidance a LIDAR/SONAR system is sufficient to ensure automated flight, but for precision landing the LIDAR/SONAR system is insufficient for effectively identifying the location of the landing platform and providing flight control inputs to guide the UAV to the landing platform. This project was developed in order to solve this problem by creating a guidance system utilizing an infrared (IR) camera to track an IR LED and blue LEDs mounted on the UAV from a RaspberryPI 3 Model B+. The RaspberryPI, using OpenCV libraries, can effectively track the position of the LED lights mounted on the UAV, determine rotational and lateral corrections based on this tracking, and, using Dronekit-Python libraries, command the UAV to position itself and land on the platform of the Husky UGV (Unmanned Ground Vehicle).
  • The practical application of a hydraulic power recovery turbine at the Valdez Marine Terminal

    Bruns, Brendon; Dandekar, Abhijit; Heimke, David; Wies, Richard (2019-05)
    A hydraulic power recovery turbine (HPRT) is a machine designed to capture energy from the pressure differential of a fluid. The HPRT recovers energy that would otherwise be lost to entropy in flowing fluid processes. When the shaft of the HPRT is coupled to an electric generator, the electricity produced can be employed for practical purposes. At the terminus of the Trans-Alaska Pipeline System (TAPS) in Valdez, favorable hydraulic conditions and electrical infrastructure exists for the application of an HPRT to generate significant power. This project will study the practical application of an HPRT as a source of clean, reliable electricity to the VMT. Installation of an HPRT has the potential to reduce diesel consumption and emissions of air pollutants at the VMT.
  • Analysis of IPR curves in North Slope horizontal producers supported by waterflood and water alternating gas EOR processes

    Abel, Alan; Awoleke, Obadare; Zhang, Yin; Dandekar, Abhijit (2019-05)
    The shape and behavior of IPR curves in waterflooded reservoirs has not previously been defined despite their common use for optimization activities in such systems. This work begins to define the behavior of IPR curves in both water flood and water‐alternating‐gas EOR systems using a fine scale model of the Alpine A‐sand. The behavior of IPRs is extended to 3 additional reservoir systems with differing mobility ratios. Traditionally derived (Vogel, Fetkovich) IPR curves are found to be poor representations of well performance and are shown to lead to non‐optimal gas lift allocations in compression limited production networks. Additionally, the seemingly trivial solution to gas lift optimization in an unconstrained system is shown to be more complex than simply minimizing the bottom hole pressure of the producing well; maximized economic value is achieved at FBHPs greater than zero psi.
  • Closest pair optimization on modern hardware

    Bright, Jason; Chappell, Glenn G.; Lawlor, Orion; Hartman, Chris (2019-05)
    In this project we examine the performance of several algorithms for finding the closest pair of points out of a given set of points in a plane. We look at four algorithms, including brute force, recursive, non-recursive, and a random expected linear time for numbers of points ranging from one hundred to one billion. In our examination, we find that on average the non-recursive is the fastest, except for limited cases of 100 points for the brute force, and 32 bit spaces for the random expected linear.
  • Enabling Data-Driven Transportation Safety Improvements in Rural Alaska

    Bennett, F. Lawrence; Metzgar, Jonathan B.; Perkins, Robert A. (2019-12)
    Safety improvements require funding. A clear need must be demonstrated to secure funding. For transportation safety, data, especially data about past crashes, is the usual method of demonstrating need. However, in rural locations, such data is often not available, or is not in a form amenable to use in funding applications. This research aids rural entities, often federally recognized tribes and small villages acquire data needed for funding applications. Two aspects of work product are the development of a traffic counting application for an iPad or similar device, and a review of the data requirements of the major transportation funding agencies. The traffic-counting app, UAF Traffic, demonstrated its ability to count traffic and turning movements for cars and trucks, as well as ATVs, snow machines, pedestrians, bicycles, and dog sleds. The review of the major agencies demonstrated that all the likely funders would accept qualitative data and Road Safety Audits. However, quantitative data, if it was available, was helpful.
  • Development of Landslide Warning System

    Riad, Beshoy; Zhang, Xiong (2019-11)
    Landslides cause approximately 25 to 50 deaths and US$1 - 2 billion worth of damage in the United States annually. They can be triggered by humans or by nature. It has been widely recognized that rainfall is one of the major causes of slope instability and failure. Slope remediation and stabilization efforts can be costly. An early warning system is a suitable alternative and can save human lives. In this project, an early warning system was developed for a 40-foot-high cut slope on the island of Hawaii. To achieve the objective, subsurface investigations were performed and undisturbed samples were collected. For the purpose of unsaturated soil testing, new testing apparatuses were developed by modifying the conventional oedometer and direct shear cells. The unsaturated soil was characterized using two separate approaches and, later, the results were discussed and compared. The slope site was instrumented for the measurement of suction, water content, displacement, and precipitation. The collected climatic data along with the calibrated hydraulic parameters were used to build an infiltration-evapotranspiration numerical model. The model estimations were compared with the field measurements and showed good agreement. The verified model was used to determine the pore-water pressure distribution during and after a 500-years return storm. Later, the pore-water pressure distribution was transferred to a slope stability software and used to study the slope stability during and after the storm. Based on a 2D slope stability analysis, the slope can survive the 500-year storm with a factor of safety of 1.20. Instrument threshold values were established for water content sensors and tensiometers using a traffic-light-based trigger criterion.
  • Laboratory investigation of infiltration process of nonnewtonian fluids through porous media in a non-isothermal flow regime for effective remediation of adsorbed contaminants

    Naseer, Fawad; Misra, Debasmita; Metz, Paul; Awoleke, Obadare; Najm, Majdi Abou (2019-12)
    Contamination of soil and groundwater have serious health implications for man and environment. The overall goal of this research is to study a methodology of using nonNewtonian fluids for effective remediation of adsorbed contaminants in porous media under nonisothermal flow regimes. Non-Newtonian fluids (Guar gum and Xanthan gum solutions) provide a high viscous solution at low concentration and these fluids adjust their viscosities with applied shear rate and change in temperature. Adjustment of viscosity with an applied rate of shear is vital for contaminant remediation because non-Newtonian shear thinning fluids can penetrate to low permeability zones in subsurface by decreasing their viscosities due to high shear rates offered by low permeability zones. The application of non-Newtonian shear thinning fluids for contaminant remediation required the improvement in understanding of rheology and how the factors such as concentration, temperature and change in shear rate impacted the rheology of fluids. In order to study the rheology, we studied the changes in rheological characteristics (viscosity and contact angle) of non-Newtonian fluids of different concentrations (i.e., 0.5g/l, 1g/l, 3g/l, 6g/l and 7g/l) at different temperatures ranging from 0 ºC to 30 ºC. OFITE model 900 viscometer and Tantec contact angle meter were used to record the changes in viscosity of fluids for an applied range of shear rate (i.e., 17.02 s⁻¹ to 1021.38 s⁻¹) and contact angles, respectively, for different concentrations of non-Newtonian fluids. Understanding the flow characteristic of non-Newtonian fluids under low temperature conditions could help in developing methods to effectively remediate contaminants from soils. Results of rheological tests manifested an increase in the viscosity of both polymers with concentration and decrease in temperature. Mid (i.e., 3g/l) to high (i.e., 6g/l and 7g/l) concentrations of polymers manifested higher viscosities compared to 0.5g/l for both polymers. Flow of high viscous solutions required more force to pass through a glass-tube-bundle setup which represented a synthetic porous media to study the flow characteristic and effectiveness of Newtonian and non-Newtonian fluids for contaminant remediation. Low concentrations of 0.5g/l were selected for flow and remediation experiments because this concentration can flow through porous media easily without application of force. The 0.5g/l of Xanthan gum and de-ionized water were used to conduct the infiltration experiments to study the flow characteristics of Newtonian and non-Newtonian fluids at 0.6°C, 5°C and 19°C in synthetic porous media. Infiltration depth of both Newtonian and non-Newtonian fluids would decrease with the decrease in temperature because of the change in their properties like dynamic viscosity, density and angle of contact. The result of comparison of Newtonian and non-Newtonian fluids showed water to be more effective in remediating a surrogate adsorbent contaminant (Dichlobenil) from the synthetic porous media at 19°C. This result was counter-intuitive to what we began with as our hypothesis. However, it was also observed later that 0.5 g/l concentration of Guar gum behaved more like a Newtonian fluid and 0.5 g/l concentration of Xanthan gum had not shown strong non-Newtonian behavior compared to higher concentrations of Xanthan gum. Hence more analysis needs to be done to determine what concentration of non-Newtonian fluid should be more effective for remediation.
  • Retrodirective phased array antenna for nanosatellites

    Long, Justin W.; Thorsen, Denise; Kegege, Obadiah; Hawkins, Joseph; Mayer, Charles (2019-12)
    This thesis presents a S-band phased array antenna for CubeSat applications. Existing state-of the-art high gain antenna systems are not well suited to the majority of CubeSats, those that fall within the 1U (10 cm x 10 cm x 10 cm) to 3U (10 cm x 10 cm x 30 cm) size ranges and in Low Earth Orbit (LEO). The system presented in this thesis is designed specifically to meet the needs of those satellites. This system is designed to fit on the 1U face (10 cm x 10 cm) of a CubeSat and requires no deployables. The use of beamforming and retrodirective algorithms reduces the pointing requirements of the antenna, easing the strict requirements that high gain antennas typically force on a CubeSat mission. Additionally, this design minimizes volume and uses low cost Commercial-off-the-Shelf (COTS) parts. This thesis discusses the theoretical background of phased array theory and retrodirective algorithms. Analysis are presented that show the characteristics and advantages of retrodirective phased antenna systems. Preliminary trade studies and design analyses show the feasibility and expected performance of a system utilizing existing COTS parts. The preliminary analysis shows that an antenna system can be achieved with ≥8.5 dBi of gain, 27dB of transmitted signal gain, 20% Power Added Efficiency (PAE) within a 1 W to 2 W power output, and an 80° effective beamwidth. Simulation results show an example antenna array that achieves 8.14 dBi of gain and an 82° effective beamwidth. Testing results on a prototype of the front-end electronics show that with minimal calibration, the beamforming and scanning error can be reduced to 5°. The power consumption and signal gain of the electronics is also verified through testing. The CubeSat Communications Platform, a CubeSat mission funded through the Air Force Research Laboratory is in Phase A design to demonstrate this antenna system, along with other experimental payloads. This thesis includes a discussion of interface control, mission requirements, operations, and a recommended experiment sequence to test and verify the antenna system on orbit.
  • Classification and signal processing of radio backscatter from meteors

    Klemm, Jared; Thorsen, Denise; Bossert, Katrina; Collins, Richard; Mayer, Charlie (2019-12)
    Ground-based radar systems are routinely used to detect the trails of ionized particles that are formed by meteoroids falling through Earth's atmosphere. The most common use for these meteor radar systems is for atmospheric wind studies of the mesosphere and lower thermosphere (80-100 km altitude). Because these meteor trails are embedded in the background winds of the middle atmosphere, atmospheric winds in that region can be measured by observing the radial velocities of the trails. There has also been a considerable amount of research over the last few decades into estimation of neutral atmospheric temperatures using the measured decay time of meteor trails. Several methods exist for estimating atmospheric temperature using meteor radar observations, but there are limitations to these approaches. This thesis focuses on examining aspects of meteor radar signal and data processing, specifically interferometry and echo classification. Interferometry using the measured signal phase differences between antennas allows for the location of meteor trails to be unambiguously determined. Classification schemes are used to identify which echoes can be modeled as underdense meteors, overdense meteors, or other potentially non-meteor echoes. Finally, based on the proposed classification scheme, this thesis examines several temperature estimation methods for both underdense and overdense echoes and discusses the current issues in this area. Preliminary results from a newly installed meteor radar at Poker Flat Research Range are also presented.
  • Development of a Computer Vision-Based Three-Dimensional Reconstruction Method for Volume-Change Measurement of Unsaturated Soils during Triaxial Testing

    Zhang, Xiong; Xia, Xiaolong (2019-10)
    Problems associated with unsaturated soils are ubiquitous in the U.S., where expansive and collapsible soils are some of the most widely distributed and costly geologic hazards. Solving these widespread geohazards requires a fundamental understanding of the constitutive behavior of unsaturated soils. In the past six decades, the suction-controlled triaxial test has been established as a standard approach to characterizing constitutive behavior for unsaturated soils. However, this type of test requires costly test equipment and time-consuming testing processes. To overcome these limitations, a photogrammetry-based method has been developed recently to measure the global and localized volume-changes of unsaturated soils during triaxial test. However, this method relies on software to detect coded targets, which often requires tedious manual correction of incorrectly coded target detection information. To address the limitation of the photogrammetry-based method, this study developed a photogrammetric computer vision-based approach for automatic target recognition and 3D reconstruction for volume-changes measurement of unsaturated soils in triaxial tests. Deep learning method was used to improve the accuracy and efficiency of coded target recognition. A photogrammetric computer vision method and ray tracing technique were then developed and validated to reconstruct the three-dimensional models of soil specimen.
  • The role of tundra vegetation in the Arctic water cycle

    Clark, Jason A.; Tape, Ken; Schnabel, William; Euskirchen, Eugénie; Ruess, Roger (2019-12)
    Vegetation plays many roles in Arctic ecosystems, and the role of vegetation in linking the terrestrial system to the atmosphere through evapotranspiration is likely important. Through the acquisition and use of water, vegetation cycles water back to the atmosphere and modifies the local environment. Evapotranspiration is the collective term used to describe the transfer of water from vascular plants (transpiration) and non-vascular plants and surfaces (evaporation) to the atmosphere. Evapotranspiration is known to return large portions of the annual precipitation back to the atmosphere, and it is thus a major component of the terrestrial Arctic hydrologic budget. However, the relative contributions of dominant Arctic vegetation types to total evapotranspiration is unknown. This dissertation addresses the role of vegetation in the tundra water cycle in three chapters: (1) woody shrub stem water content and storage, (2) woody shrub transpiration, and (3) partitioning ecosystem evapotranspiration into major vegetation components. In Chapter 1 I present a method to continuously monitor Arctic shrub water content. The water content of three species (Salix alaxensis, Salix pulchra, Betula nana) was measured over two years to quantify seasonal patterns of stem water content. I found that spring uptake of snowmelt water and stem water storage was minimal relative to the precipitation and evapotranspiration water fluxes. In Chapter 2, I focused on water fluxes by measuring shrub transpiration at two contrasting sites in the arctic tundra of northern Alaska to provide a fundamental understanding of water and energy fluxes. The two sites contrasted moist acidic shrub tundra with a riparian tall shrub community having greater shrub density and biomass. The much greater total shrub transpiration at the riparian site reflected the 12-fold difference in leaf area between the sites. I developed a statistical model using vapor pressure deficit, net radiation, and leaf area, which explained >80% of the variation in hourly shrub transpiration. Transpiration was approximately 10% of summer evapotranspiration in the tundra shrub community and a possible majority of summer evapotranspiration in the riparian shrub community. At the tundra shrub site, the other plant species in that watershed apparently accounted for a much larger proportion of evapotranspiration than the measured shrubs. In Chapter 3, I therefore measured partitioned evapotranspiration from dominant vegetation types in a small Arctic watershed. I used weighing micro-lysimeters to isolate evapotranspiration contributions from moss, sedge tussocks, and mixed vascular plant assemblages. I found that mosses and sedge tussocks are the major constituents of overall evapotranspiration, with the mixed vascular plants making up a minor component. The potential shrub transpiration contribution to overall evapotranspiration covers a huge range and depends on leaf area. Predicted increases in shrub abundance and biomass due to climate change are likely to alter components of the Arctic hydrologic budget. The thermal and hydraulic properties of the moss and organic layer regulate energy fluxes, permafrost stability, and future hydrologic function in the Arctic tundra. Shifts in the composition and cover of mosses and vascular plants will not only alter tundra evapotranspiration dynamics, but will also affect the significant role that mosses, their thick organic layers, and vascular plants play in the thermodynamics of Arctic soils and in the resilience of permafrost.
  • Laboratory and Field Evaluation of Modified Asphalt Binders and Mixes for Alaskan Pavements

    Liu, Jenny; Liu, Jun (2019-08)
    In order to properly characterize modified asphalt binders and mixes for Alaskan pavements, this study evaluated properties of 13 asphalt binders typically used in Alaska from three different suppliers, and 10 hot mix asphalt (HMA) mixtures which were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (G*), and phase angle (δ) at high performance temperatures, multiple stress creep recovery rate and compliance, bending beam rheometer stiffness and m-value, Glover-Rowe parameter, ΔT, rheological index, and crossover frequency for binders, and rut depth, critical strain energy release rate (Jc), Indirect tensile (IDT) creep stiffness and strength for mixtures. Binder cracking temperatures were determined using asphalt binder cracking device. Mixture cracking temperatures were determined with IDT creep compliance and strength data. It was found that rutting and cracking resistances of the mixtures with highly modified binders were better than the mixture with unmodified asphalt binder (PG 52-28). Future recommendations for highly modified asphalt binders applications and research were provided based on laboratory testing results and field survey evaluation.
  • Reaching Out to Tribal Communities: Lessons Learned and Approaches to Consider

    Awwad-Rafferty, Rula; Chang, Kevin; Brown, Helen (2019-12-31)
    When transportation safety decision-making is desired, the involvement and engagement with a community is essential. A streamlined delivery of a project or program is more likely to occur when active dialogue and an exchange of ideas occurs in advance and occurs frequently. This is particularly important in tribal communities, who value sustained relationships and represent the focus population of this study. The research team, on six separate occasions, met with local and regional tribal leaders to explore and discuss transportation safety needs within and outside tribal communities, as well as discern the recommended approaches to foster ongoing dialogue about these needs. In all cases these discussions closely correlated with existing research studies or activities; transportation safety and equity is not seen as separate from other tribal foci and community needs. Specific recommendations to consider, in no particular order, included the following: invest respectfully enough time for people to talk; tribes think long-term and consider the impact of any decision from a long-term viewpoint so an iterative process and re-sharing of ideas is critical; the power of decision is in the hands of the tribe and its members; do not lump tribes together as each tribe is sovereign and unique and every community should be expected to think differently; all tribes are unique as is the environmental and social context; to disseminate information widely and iteratively, do so when there is a large group or event; be sure to understand the Tribal governance, decision making, and organizational structure; know who is the tribal Chairman or Chairwoman; and develop an emic and etic understanding of the community.
  • Highly Abrasion-resistant and Long-lasting Concrete

    Liu, Jenny; Murph, Diane (2019-08)
    Studded tire usage in Alaska contributes to rutting damage on pavements resulting in high maintenance costs and safety issues. In this study binary, ternary, and quaternary highly-abrasion resistant concrete mix designs, using supplementary cementitious materials (SCMs), were developed. The fresh, mechanical and durability properties of these mix designs were then tested to determine an optimum highly-abrasion resistant concrete mix that could be placed in cold climates to reduce rutting damage. SCMs used included silica fume, ground granulated blast furnace slag, and type F fly ash. Tests conducted measured workability, air content, drying shrinkage, compressive strength, flexural strength, and chloride ion permeability. Resistance to freeze-thaw cycles, scaling due to deicers, and abrasion resistance were also measured. A survey and literature review on concrete pavement practices in Alaska and other cold climates was also conducted. A preliminary construction cost analysis comparing the concrete mix designs developed was also completed.
  • A Bio-Wicking System to Prevent Frost Heave in Alaskan Pavements: Phase II Implementation

    Galinmoghadan, Javad; Zhang, Xiong; Lin, Chang (2019-11)
    Water within pavement layers is the major cause of pavement deterioration. High water content results in significant reduction in soil’s resilient behavior and an increase in permanent deformation. Especially in cold regions, frost heave and thaw weakening cause extensive damage to roads and airfields. Conventional drainage systems can only drain gravity water not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. In this report, continuous research was conducted to verify the effectiveness of the wicking fabric in mitigating frost boil issues in Alaskan pavemnets. Two test sections were selected at two low volume roads on the campus of the University of Alaska Fairbanks. Soil moisture and temperature sensors were installed within the road embankments. The monitored data was used to analyze the soil migrations and evaluate the drainage performance of the wicking fabric. Preliminary monitoring results showed that the wicking fabric was effective in mitigating the frost boil problem.
  • Use of Cellular Concrete for Air Convection Embankment to Protect Permafrost Foundations in Cold Regions: Feasibility Study

    Liu, Jenny; Wu, Hanli (2019-08-15)
    The air convection embankment (ACE) is a technique used to protect permafrost from thawing in road construction in cold regions. However, the desired materials needed for ACE are not readily available, which prevents its extensive use in Alaska. To overcome the limitation of traditional ACE, and further improve the cooling effect of ACE, this study investigated the feasibility of using cellular concrete as an alternative material for ACE in cold regions. The heat transfer patterns of the cellular concrete ACE, the crushed-rock ACE, and the sand/gravel embankment were studied using the numerical simulation. The results of the present study show that the cooling performance of both cellular concrete ACE and crushed-rock ACE are superior to the traditional sand/gravel embankment. The cellular concrete ACE has better heat insulation property in the summer, and the crushed-rock ACE has stronger natural convection in winter. For the annual cooling efficiency of the two different ACE techniques, the proposed cellular concrete ACE has a better cooling effect on the foundation soil than the crushed-rock ACE. These results indicate that the thermal conductivity and specific heat capacity of construction materials have significant impacts on the performance of the ACE.

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