• Characterization and implementation of stress dependent resilient modulus of asphalt treated base for flexible pavement design

      Li, Peng; 鹏 李; Liu, Juanyu; Connor, William; Zhang, Xiang; Shur, Yuri; Saboundjian, Stephan (2013-08)
      Asphalt treated base (ATB) is the most commonly used type of stabilized material in pavements because of material availability and relatively low cost in Alaska. The treatment enhances the material's properties to overcome deficiencies in some marginal materials. Resilient modulus (MR) of these materials is an essential pavement design input. Currently, in the Alaska Flexible Pavement Design (AKFPD) Manual, MRS of ATBs were back calculated using testing results of falling weight deflectometer (FWD). There is a need for an accurate laboratory characterization of these materials. In this study, the MRS of hot asphalt treated base (HATB), emulsifed asphalt treated base (EATB), foamed asphalt treated base (FATB), and a mixture of reclaimed asphalt pavement (RAP) and D-1 aggregate at a 50: 50 ratio (RAP 50:50) were measured using repeated triaxial tests. D-1 granular materials used for base course construction were collected from three regions in Alaska. HATB specimens were compacted using Superpave gyratory compactor and three binder contents were used: 2.5%, 3.5% and 4.5%. EATB and FATB specimens were compacted according to ASTM D1557 and three residual binder contents were used: 1.5%, 2.5% and 3.5%. RAP 50:50 was also compacted according to ASTM D1557 and no additional additives were added. MR was measured at three temperatures (i.e. -10°C, 0°C, 20°C for HATB, EATB and FATB; -10°C, -2°C, 20°C for RAP 50:50). The stress-dependent property of MR was successfully characterized by the modified universal soil model, in which the MR was expressed as a function of bulk stress (θ) and octahedral shear stress (τoct). Generally, MR increased with an increase of θ and decreased with an increase of τoct. Stress-dependent patterns of each type of ATB were analyzed and discussed. Predictive equations for MR were developed for all types of ATBs investigated in this study. The equations were based on the modified universal soil model. The material properties (i.e. binder content and percentage fracture surface), temperature and the interactions among them were incorporated into equations. The developed predictive equations had very high coefficient of determination (R²). The R² s of equations HATB_10, EATB_10, FATB_10 and RAP_9, in which the influencing factors and second order interactions among factors were included, were all greater than 99%. These equations can be also used to estimate nonlinear elastic constants of ATBs in the modified universal soil model (i.e. k₁, k₂ and k₃). The stress dependent property of MR was incorporated into pavement structural analysis using the finite element method (FEM) program Abaqus through user defined material that was programmed in the user subroutine. Comparisons were made between pavement responses obtained from nonlinear FEM and traditional linear elastic layered system. The representative MR of ATBs were determined and recommended based on the equivalent critical pavement response of the typical Alaska flexible pavement structure. Predictive equations were developed to estimate the critical pavement responses. The equations were developed through regression analyses using a database generated from 16,848 nonlinear pavement FEM analyses, which covered a variety of pavement structure combinations. These nonlinear pavement analyses were implemented through the function of a parametric study provided in Abaqus FEM package. In total 9 independent variables were included, which were the thickness of the surface course, base course, and subbase, moduli of HMA, subbase and subgrade, and nonlinear elastic constants of ATB (i.e. k₁ k₂ k₃) in the MR model. The interactions among these variables were also included. The R²s of predictive equations were at least 0.9725. The predictive equations can be used for routine pavement analysis and design purposes.
    • Characterization and washability studies of raw coal from the Little Tonzona Field, Alaska

      Rao, P.D.; Walsh, D.E.; Phillips, N.; Charlie, K.G. (University of Alaska Mineral Industry Research Laboratory, 1991)
      Coal occurs in an isolated exposure of Tertiary, non-marine sedimentary rocks along the southwest bank of the Little Tonzona River, near Farewell, Alaska. The Little Tonzona River coal field is located approximately 150 air miles northwest of Anchorage, Alaska, and 210 air miles southwest of Fairbanks, Alaska; near the boundaries of Denali National Park. The Alaska Railroad and the Parks Highway are approximately 100 air miles from the coal field at their nearest point. The village of McGrath, on the Kuskokwim River, is located approximately 90 miles to the west (1). An impressive outcrop of coal-bearing Tertiary sediments is exposed for a distance of more than 275 feet on the west bank of the Little Tonzona River (Figure 1). More than seven coal beds, ranging in thickness from 3 feet ta 30 feet, with a cumulative thickness of over 134 feet, are interbedded with clay beds up to 40 feet thick. The clays are fine textured, extremely plastic, light grey to nearly white bentonites andlor tonsteins. Doyon Ltd., an ANSCA Native Corporation, holds land selections covering the inferred limits of the coal field. During 1980 and 1981, Doyon entered into exploration agreements with McIntyre Mines Inc. of Nevada. The two season exploration program took place from June 1,1980 through August 22,1980 and from May 27,1981 through August 22, 1981. During the 1980 field season, geologic mapping, prospecting, stratigraphy, trenching and bulk sampling of all coal outcrops were performed. This produced a total of 34 samples, which were taken for analysis. In 1981, six diamond drill holes with a cumulative length of 2,935 feet were completed. Core recovery was close to 90%, and a total of 147 coal samples, which represented 802.8 cumulative feet of coal, were taken for analysis. The exploration program confirmed a strike length of over 3 miles to the southwest from the main river bank exposure. Northward extension is unknown at this time. Although outcrop exposure is poor away from the river banks, burnout zones resulting from past coal bed fires form a resistant, recognizable on strike feature in the relatively unindurated Tertialy sequence. The appearance of these burnout zones along strike is often the only surface indication of the buried coal-bearing strata. Well preserved plant fossil impressions in the baked clays date the deposit as probable Miocene (2). Coal characterization and washability studies were performed on all coal samples by the Mineral Industry Research Laboratory of the University of Alaska Fairbanks. This work was conducted under the direction of Dr. P.D. Rao, Professor of Coal Technology.
    • Characterization of Alaska North Slope oils for wax deposition

      Anyanwu, Okechukwu Ndubuisi; Zhu, Tao; Chukwu, Godwin A.; Dandekar, Abhijit; Zhou, Wendy (2007-08)
      Wax deposition during crude oil production is a major problem that has plagued the oil industry for decades especially in cold environments such as Alaska North Slope (ANS) fields, with adverse consequences in huge mitigation cost and lost production. It is therefore imperative to adequately and accurately identify the conditions for wax precipitation and deposition in order to optimize operation of the production systems of ANS. In order to assess ANS crude's potential for wax precipitation, Viscometry and Cross Polarization Microscopy (CPM) are used to determine the temperature at which paraffins begin to precipitate from ANS dead oils. Wax dissolution temperatures (WDT) are also determined by CPM. Results show that wax precipitation is possible at temperatures as high as 41°C (106°F) while it takes up to 50°C (122°F) to get all waxes back into solution. The CPM technique was more sensitive while Viscometry results did not provide a high level of certainty in some samples and therefore appear over-estimated relative to CPM results. Previous thermal history was observed to influence test results. Pour point, viscosity, density and specific gravity have also been measured. Pour point results indicate that oil could form gel in the temperature range 12°C (53.6°C) to less than -31°C ( -23.8°F).
    • Characterization of Alaska's coals

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1974)
      Coal characterization is a systematic determination of those properties of coal, or of its constituents, that affect its behavior when used. It will help in planning for recovery and use of the extensive Alaskan coal deposits, which have proven reserves of 130 billion tons. This estimate is of necessity based on widely scattered outcrops and meager drill hole data, and the reserves in the Cook Inlet region and the Northern Alaska field are considered to be several fold this figure.
    • Characterization of Alaskan HMA Mixtures with the Simple Performance Tester

      Li, Peng; Liu, Juanyu (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • Characterization of Alaskan Hot-Mix Asphalt containing Reclaimed Asphalt Pavement Material

      Liu, Jenny; Zhao, Sheng; Li, Lin (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-06)
      In order to properly characterize Alaskan HMA materials containing RAP, this study evaluated properties of 3 asphalt binders typically used in Alaska, PG 52-28, PG 52-40, and PG 58-34, and 11 HMA mixtures containing up to 35% RAP that 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, MSCR recovery rate and compliance, BBR stiffness and m-value, DTT failure stress and strain for binders, and dynamic modulus, flow number, IDT creep stiffness and strength for mixtures. Binder cracking temperatures were determined through Thermal Stress Analysis Routine (TSAR) software along with BBR and DTT data. Mixture cracking temperatures were determined with IDT creep stiffness and strength data. It was found that rutting may not be a concern with Alaskan RAP mix, while low-temperature cracking concerns may still exist in RAP mix in Alaska. A savings of $13.3/ton was estimated for a 25% RAP mix, with consideration of Alaskan situations. Many recommendations for future RAP practice and research are recommended based on testing results and cost analysis.
    • Characterization of Asphalt Treated Base Course Material

      Li, Peng; Liu, Juanyu (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2010)
    • Characterization of coal products from high temperature processing of Usibelli low-rank coals

      Rao, P.D.; Walsh, D.E.; Wilson, W.; Li, YuFu (University of Alaska Mineral Industry Research Laboratory, 1991)
      This research project was conducted in association with Gilbert/Commonwealth Inc. as part of an overall techno-economic assessment of high temperature drying of low-rank coals. This report discusses the characteristics of the dried/pyrolyzed products of two high temperature, evaporative processes and the dried product from a hydrothermal process. The long term goal of this and other coal drying studies conducted at MIRL, was to define drying technologies that have significant and real potential to competitively move Alaska's, low-rank coals (LRCs) into the export, steam coal market of the Pacific Rim. In 1990, Japan imported 33 million metric tons (mt) of steam coal with an additional 39 million mt imported by other Far East nations(2). Australia dominates the export steam coal market to these Pacific Rim countries and exported 48 million mt in 1990 and an additional 61 million mt of metallurgical coal(2). The worldwide steam coal export market has been expanding rapidly, from 20 million mt in 1973 to 150 million mt in 1989, and is expected to double to nearly 300 million mt by the end of the century(3). Could Alaska capture only 3% of the projected new world steam coal market, which is not an unreasonable expectation, the value of the state's coal exports would soar from nominally $28 million per year to over $100 million per year. However, without development of economical methods for drying/stabilizing Alaskan LRCs, the only increase in export of Alaskan coals may be from the few "higher rank" coals within a "reasonable" transport range of the existing Alaska rail system or tidewater. Presently the coal from the Usibelli Coal Mine is the only low-rank coal exported internationally as a steam coal; primarily for its blending properties with other coal to improve combustion. But for Alaskan low-rank coals to truly stand on their own merits, economical drying processes must be developed that produce a physically and chemically stable dried product. The technologies that have the most potential for increasing the use of Alaskan coals are those that can reduce the moisture content of these coals economically, and produce a fuel that is accepted in the international market place. Drying technologies will no doubt differ, depending on the end use of the fuel; be it dried lump coal, briquettes or pellets for pulverized coal or stoker applications, or concentrated coal-water fuels made from hot water dried LRCs. There are a number of developing processes that may work with Alaskan coals. Some drying processes, however, have been plagued by the production of excessive amounts of coal fines, Since the demand for Alaskan coal is currently limited to lump size coal, large quantities of fines are a definite liability. In this study, two high temperature drying/pyrolysis processes and one hydrothermal process were investigated. The high temperature drying/pyrolysis processes were conducted at (1) the Western Research Institute, (WRI) an affiliate of the University of Wyoming Research Corporation, Laramie, WY, and (2) Coal Technology Corporation (CTC) of Brisol, VA. Hydrothermal processing was conducted at MIRL, University of Alaska Fairbanks. A summary of these processes and the products they produced follows.
    • Characterizing the berthing load demand at Alaska Department of Transportation and Public Facilities Ferry Landings

      Hutchinson, Jonathan; Metzger, Andrew; Hulsey, Leroy; Dong, YongTao (2011-08)
      This report provides design guidelines and recommendations for side-berthing loads on ferry landing structures. Berthing loads on ferry berthing structures are not well understood due to a lack of information and research for ferry class vessels. The load criteria for the design of ferry berthing structures are thus often based on a number of assumptions, often leading to uneconomical or unreliable structures. The Alaska Department of Transportation (AKDOT&PF) recognizes the need for an improved information base on berthing loads from ferry class vessels, for the design and operation of future facilities within the Alaska Marine Highway System (AMHS). This study involves a one year empirical investigation into side-berthing loads at the Auke Bay ferry landing located in Juneau, Alaska. Measurements of fender displacement, approach velocity, and pile strain were used to determine berthing loads from scheduled berthings from four different vessels. Measured parameters were analyzed statistically, and used to establish distributions and design recommendations for berthing energy, force, velocity, and berthing coefficient based on reliability theory. This study provides an assessment of load criteria currently used by the AK DOT&PF Marine Department, as well as design load recommendations for both service and ultimate side-berthing loads from ferry class vessels.
    • Characterizing the berthing load environment of the Seattle ferry teminal, Bremerton slip

      Kwiatkowski, Jason E. (2012-12)
      This manuscript characterizes and presents design recommendations for berthing demands on ferry landing structures. There is a lack of research focused on the berthing load demand imparted by ferry class vessels, therefore the load criteria used for design is often based on a number of assumptions. This study involved a one-year field study of the structural load environment of wingwalls at the Bremerton Slip of the Seattle Ferry Terminal, located in Elliott Bay adjacent to Seattle, Washington. Measurements of marine fender displacement, vessel approach distance with respect to time, and. pile strain were used to determine berthing demands. Berthing event parameters were characterized using the Python programming language, compiled, and analyzed statistically. Probability theory was used to provide design value recommendations for berthing energy, force, approach velocity, berthing factor, and berthing coefficient. This study presents a number of engineering design aids intended to quantify the berthing load environment of wingwalls in the Washington State Ferry System.
    • Characterizing the Load Environment of Ferry Landings for Washington State Ferries and the Alaska Marine Highway System

      Metzger, Andrew T.; Kwiatkowski, Jason; Hutchinson, Jonathan (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, Washington State Department of Transportation, 2013)
    • Chemical and microbial characterization of North Slope viscous oils for MEOR application

      Ghotekar, Ashish L.; Patil, Shirish; Khataniar, Santanu; Dandekar, Abhijit (2007-12)
      Viscous oil reservoirs tend to be low-energy, low-gas/oil-ratio systems with high viscosities and are difficult to produce, transport and refine by conventional methods. Some of the commonly considered viscous oil recovery methods include processes such as steam flooding, in-situ combustion and miscible gas injection. The large viscous oil deposits in the ANS cannot be produced entirely by conventional methods like pressure displacement or waterflooding. Other methods such as miscible (gas injection and water alternating gas (WAG) also have limited success. Microbial enhanced oil recovery (MEOR) is one of the techniques for improving the oil recovery for viscous deposits. This method has not yet been applied to the ANS fields. This study includes experimental work to analyze the application of MEOR to the ANS oil fields. A microbial formulation was developed in order to simulate the MEOR. Coreflooding experiments were performed to simulate the improved recovery oil recovery and quantify the incremental oil recovery. Properties like viscosity, density and chemical composition of oil were monitored to propose a mechanism of oil recovery. Terminal restriction fragment length polymorphism (T-RFLP) was performed on the oil samples to qualitatively study the effect of the microbial formulation on a molecular scale.
    • Chemical characterization of liquefaction products of an inertinite enriched northern Alaska coals

      Mayasandra, Venugopal (University of Alaska Mineral Industry Research Laboratory, 1989)
      A Northern Alaskan coal rich in inertinites was further enriched by density gradient separations. The degree of condensation of the enriched coal was estimated to be low, mainly 3 ring. The reactivity of the inertinite enriched coal was determined by comparing yields from direct liquefaction with H2 at 0 and 30 minute residence times, 425°C, using an H-donor solvent in one case and moly-catalyst in the other with H2 pressures of 500 and 1000 psig respectively. Solid products were analyzed by Fourier Transform Infrared Spectroscopy while the hexane solubles were separated into various chemical classes, viz. alkanes, neutral polycyclic aromatic compounds, hydroxy polycyclic aromatic oxygen heterocycles, and secondary, tertiary amino polycyclic aromatic compounds. The chemical compounds in these fractions were further analyzed by gas chromatography - mass spectrometry (GC-MS)an dcapillary gas chromatography. This work confirmed earlier data showing that inertinites are not as determinental to liquefaction as previously thought.
    • 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.
    • Clearing Alaskan Water Supply Impoundments : Data

      Smith, Daniel W.; Justice, Stanley R. (University of Alaska, Institute of Water Resources, 1976-04)
      The data contained in IWR-67 (Clearing Alaskan Supply Impoundments: Management and Laboratory Study) was collected to determine the effect on water quality of five proposed Alaskan reservoirs as a function of the extent of clearing in site preparation. The study developed a methodology for such analysis and made recommendations as to the best clearing alternatives for each reservoir site. For graphic presentation and evaluation of the data, refer to IWR-67 and IWR-67-A (Literature Review), published by the Institute of Water Resources, University of Alaska, Fairbanks, Alaska.
    • Clearing Alaskan Water Supply Impoundments : Literature Review

      Justice, Stanley R.; Smith, Daniel W. (University of Alaska, Institute of Water Resources, 1976-04)
      This literature review was prepared in conjunction with a research project evaluating the effect on water quality of five proposed Alaskan Reservoirs and recommending clearing alternatives. For the results of the laboratory study and discussion of impoundment management in northern regions refer to "Clearing Alaskan Water Supply Impoundments, Management and Laboratory Study" (IWR-67). The data developed in the laboratory portion of the study is contained in IWR-67-B. Contact the Institute of Water Resources if access to this material is desired. Much of the material in this review was derived from the paper "The Effect of Reservoirs on Water Quality" which was prepared by Stan Justice in partial fulfillment of the requirements for the degree of Master of Science in Environmental Quality Engineering.
    • Clearing Alaskan water supply impoundments: management, laboratory study, and literature review

      Smith, Daniel W.; Justice, Stanley R. (University of Alaska, Institute of Water Resources, 1976-04)
      Water supply impoundments in northern regions have seen only limited application. Reasons for the lack of use of such impoundments include the following: 1) little demand for water due to the low population densities and rustic life styles; 2) a lack of conventional distribution systems in many communities; 3) poorly developed technology for construction of dams on permafrost; 4) adequacy of existing river, lake, ice, and lagoon water supplies; 5) shortage of capital to finance the high cost of construction in remote regions.
    • Climate Change Impact Assessment for Surface Transportation in the Pacific Northwest and Alaska

      Lee, Ming; MacArthur, John; Mote, Philip; Ideker, Jason; Figliozzi, Miguel (Alaska University Transportation Center, Washington State Department of Transportation, 2012)
    • Climatic and physiographic drivers of peak flows in watersheds in the North Slope of Alaska

      Hinzman, Alexa Marion Hassebroek; Stuefer, Svetlana; Arp, Christopher; Barnes, David (2017-08)
      The failure to accurately predict peak discharge can cause large errors in risk analysis that may lead to damage to structures and in some cases, death. Creating linear regression (LR) equations that accurately predict peak discharges without historic data provides a method to estimate flood peaks in ungauged watersheds on the North Slope of Alaska. This thesis looks at the independent variables that drive, or are significant in predicting snowmelt peak discharge in the North Slope watersheds. The LR equations created use independent variables from meteorological data and physiographic data collected from four watersheds, Putuligayuk River, Upper Kuparuk River, Imnavait Creek and Roche Moutonnée Creek. Meteorological data include snow water equivalent (SWE), total precipitation, rainfall, storage, length of melt. Physiographic data summarize watershed area (2.2 km2 to 471 km2) and slope (0.15:100 to 2.7:100). This thesis compared various Flood Frequency Analysis techniques, starting with Bulletin 17B, multiple USGS regional methods and finally created LR equations for each watershed as well as all four watersheds combined. Five LR equations were created, three of the LR equations found SWE to be a significant predictor of peak flows. The first equation to estimate peak flows for all watersheds used only area and had a high R2 value of 0.72. The second equation for all watersheds included area and a meteorological independent variable, SWE. While the evidence presented here is quite promising that meteorological and physiographic data can be useful in estimating peak flows in ungauged Arctic watersheds, the limitations of using only four watersheds to determine the equations call for further testing and verification. More validation studies will be needed to demonstrate that viable equations may be applied to all watersheds on the North Slope of Alaska.
    • 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.