Now showing items 1-20 of 91

    • Alaska-Canada Rail Link Economic Benefits

      Watts, Teresa; Peter Wallis Consulting Limited; Metz, Paul A. (2019-07)
      Construction of the 1,740 km Alaska-Canada Rail Link (ACRL) between Fort Nelson, BC and Delta Junction, Alaska to join the North American rail system to the Alaska Railroad will result in tremendous economic benefits for Canada and the US. The ACRL will provide valuable additional east-west rail capacity and tidewater access to the Pacific, hugely benefitting not only the Yukon and Eastern Alaska regions, into which it will introduce rail transport for the first time, but throughout both countries. The economic benefits of ACRL construction are consistent with Canadian government’s desire to promote Northern development and comparable in significance to those of Canadian Pacific Railway in the 1880’s and the St. Lawrence Seaway in the 1950’s. Construction of the ACRL alone will bring unprecedented economic stimulus to the region in terms of job creation, wages and income tax revenue over multiple years. Table 7-1 below summarizes the benefits from ACRL construction for the Yukon, BC and Canada as a whole. However, these estimates are conservative as they exclude benefits associated with pre-construction activities, railway operation post-construction, sales taxes and corporate taxes as well as all such benefits that will accrue to Alaska and the US.
    • COMPARISON OF POLYSTYRENE EXPANDED AND EXTRUDED FOAM INSULATION IN ROADWAY AND AIRPORT EMBANKMENTS

      Connor, Billy (2019-04)
      The differences in performance of expanded polystyrene rigid foam insulation (EPS) and extruded polystyrene rigid foam insulation (XPS) has been debated since the 1980’s. Esch’s 1986 study showed that the R-value of EPS degraded more than XPS when installed in roadway embankments. Pouliot and Savard (2003) noted similar results. This study adds 15 additional samples from three additional installations to the dataset. Using the combined data from these sites, ratios of R-values of EPS/XPS were developed which can be used to estimate equivalent thicknesses of the two products. R-value multipliers were also developed which allow thicknesses of the products to be computed based on the long-term performance of the insulation used in roadway and airport embankments. The data appear to be consistent between Esch, Pouliot and Savard and this study. There is no consensus as to how the data or ratios are to be applied if at all. However, the study does provide two approaches. A multiplier can be applied to each product which provides a long-term equivalent thickness for each product. Alternatively, a multiplier can be applied to the R-value of each product which yields a thickness that yields a long-term R-value of in-service applications.
    • Performance of Tencate Mirafi PGM-G4 Interlayer-Reinforced Asphalt Pavements in Alaska

      Li, Peng; Liu, Jenny; Eckman, Paul (Alaska University Transportation Center, 2014-08)
      Geosynthetics has been used in hot mix asphalt (HMA) overlays in a variety of design and construction situations for more than three decades. A number of positive benefits have been identified such as waterproofing control for base and subgrade protection, improved fatigue resistance and reduced propagation of reflective cracks. In cold regions such as Alaska and other northern states, pavements are more prone to distresses due to extreme climatic conditions. Research is needed to explore how interlayers functions in asphalt pavements in cold regions. The interlayers used for pavement reinforcement applications and available in the market are primarily biaxial. Biaxial grids with equal strength in both the machine and cross machine directions allow stress transfer at low strain mainly in longitudinal and transverse directions. The new PGM-G4 paving composite developed by Tencate Geosynthetics contains multi-axial fiberglass filament yarn, which changes the aperture geometry from a rectangular to a quad angular grid structure. This unique feature improves the structure radial stiffness and efficiently distributes stress from surface layer to the geogrid throughout the full 360o. This isotropic feature could deliver optimal asphalt concrete (AC)/grid interaction and more efficient reinforcement. There is a need to identify/validate its expected performance and added value over conventional biaxial grids. Hence, a study has been conducted on interlayer-reinforced asphalt pavements in Alaska that included two phases: laboratory index testing (Phase I) and field performance evaluation (Phase II). Phase I focused on laboratory evaluation of engineering properties of PGM-G4 composite paving grid-reinforced asphalt pavement structure and comparison with other types of interlayers. Five types of interlayers were evaluated in this study for various laboratory tests and they were PGM-G4 (multi-axial composite grid), PGM-G100/100 and PGM-G50/50 (bi-axial composite grid), TruPave® (engineered paving fiberglass and polyester hybrid mat), and MPV500 (conventional polypropylene interlayer). The performance tests included asphalt retention and grab strength tests of interlayers, and shear strength, permeability and indirect tension (IDT) tests of interlayer-reinforced asphalt mixtures. Further, a typical Alaska flexible pavement structure was used, and pavement structure analyses and simulation were conducted by Bisar, Alaska Flexible Pavement Design (AKFPD) and ABAQUS programs to investigate the effects of paving interlayers on the pavement performance.
    • Specialized Testing of Asphalt Cements from Various ADOT&PF Paving Projects

      Hesp, Simon A. M. (Alaska University Transportation Center, 2015-06-10)
      The Alaska Department of Transportation and Public Facilities (ADOT&PF) sampled five different asphalt cements for specialized testing at Queen’s University in Kingston, Ontario. This report documents and discusses the findings. The tested asphalts were: PG 58-34, PG 52-40D, PG 52-40N, PG 58-28, and PG 64-28. Testing results showed that grade losses according to Ontario’s LS-308 Extended Bending Beam Rheometer (EBBR) ranged from 3.4°C to 6.3°C. Losses according to Ontario’s LS-228 Modified Pressure Aging Vessel (PAV) ranged from 0°C to 7.3°C. Grade losses of 3°C and higher are significant in terms of their ability to reduce pavement life cycles. Double-edge-notched tension (DENT) tests according to Ontario’s LS-299 DENT protocol were done on PAV residues. The critical crack tip opening displacement (CTOD) was determined and, at 15°C, it varied from a low of 19 mm for the PG 58-28 to a high of 175 mm for the PG 58-34. The PG 58- 40D showed a CTOD of 139 mm, contrasting with the low polymer PG 52-40N at only 36 mm, a nearly four-fold difference. All the results obtained from this specialized testing effort suggest that these materials will provide significant differences in performance. This report provides recommendations on how to obtain better value for money by implementing a few simple changes to the ADOT&PF asphalt cement specifications.
    • Geophysical Applications for Arctic/Subarctic Transportation Planning

      Schnabel, William E.; Fortier, Richard; Kanevskiy, Mikhail; Munk, Jens; Shur, Yuri; Trochim, Erin (Alaska University Transportation Center, 2014-07)
      This report describes a series of geophysical surveys conducted in conjunction with geotechnical investigations carried out by the Alaska Department of Transportation and Public Facilities. The purpose of the study was to evaluate the value of and potential uses for data collected via geophysical techniques with respect to ongoing investigations related to linear infrastructure. One or more techniques, including direct-current resistivity, capacitive-coupled resistivity, and ground-penetrating radar, were evaluated at sites in continuous and discontinuous permafrost zones. Results revealed that resistivity techniques adequately differentiate between frozen and unfrozen ground, and in some instances, were able to identify individual ice wedges in a frozen heterogeneous matrix. Capacitive-coupled resistivity was found to be extremely promising due to its relative mobility as compared with direct-current resistivity. Ground-penetrating radar was shown to be useful for evaluating the factors leading to subsidence in an existing road. Taken as a whole, the study results indicate that supplemental geophysical surveys may add to the quality of a geotechnical investigation by helping to optimize the placement of boreholes. Moreover, such surveys may reduce the overall investigation costs by reducing the number of boreholes required to characterize the subsurface.
    • Seismic Performance of Reinforced Concrete Filled Steel Tubes in Soil

      Aguirre-Realpe, Diego A.; Kowalsky, Mervyn J.; Nau, James M.; Gabr, Mohammed (Alaska University Transportation Center, 2016-12)
      Reinforced concrete filled steel tube pile-columns are structural elements commonly used in bridge supports in high seismic regions because RCFSTs provide increased levels of strength, ductility, and energy dissipation as compared with traditional systems such as reinforced concrete (RC) or steel substructures. This study includes experimental and analytical studies that considered three main parameters: the diameter-to-thickness (D/t) ratio, the above-ground length (La), and the soil stiffness.
    • Creosote Treated Timber in the Alaskan Marine Environment

      Perkins, Robert (Alaska University Transportation Center, 2009-08)
      Creosote is a wood preservative that is used in marine structures in Alaska, such as piles, docks, and floating structures. Some of the PAH chemicals in creosote are toxic to marine organisms, and resources agencies and environmental groups question its use. Mesoscale testing of creosoted wood has not indicated significant negative effects of wood treated with Best Management Practices (BMP), which is now standard practice. The EPA pesticide recertification of creosote required only the use of BMP or a risk assessment. The National Marine Fisheries Service issued draft guidelines for wood preservatives, which does not preclude use of creosote, but suggest a risk assessment if the qualities of treated wood are large or they are installed in sensitive areas. This report recommends consideration of the risks of creosote and presents an algorithm for analyzing the risks. Many applications require only an overview risk assessment. Applications of large quantities of preserved wood or in sensitive areas should have a more formal risk assessment. The report and the EPA recertification suggest a screening assessment published by the Western Wood Preservers Institute. If the screening indicates further assessment is needed, the report points to more detailed assessments.
    • Evaluation of Warm Mix Asphalt for Alaska Conditions

      Liu, Juanyu (Alaska University Transportation Center, 2010-04)
      In line with a field demonstration project of WMA using Sasobit conducted in Southeast Alaska, this study focused on experimentally assessing the engineering properties of Sasobit modified WMA binders and mixes. Performance tests of binders were conducted according to Superpave specification to assess the correlation between the content of additives, and Superpave performance grade (PG) and stiffness of modified binders. Tests conducted to assess the performance of WMA included 1) permanent deformation (rutting) susceptibility, 2) low temperature cracking performance including tensile strength and tensile creep compliance properties, 3) moisture susceptibility, and 4) dynamic modulus |E*|. Laboratory investigation of Sasobit-modified binders and WMAs in this study identified a lot of engineering benefits of WMAs using Sasobit over traditional HMA. WMAs using Sasobit with reduced mixing and compaction temperatures, improved workability and rutting resistance, and insignificant effect on moisture susceptibility favorably indicated the suitability of this WMA technology for Alaska conditions. The indirect tension test (IDT) results showed degraded resistance to low temperature cracking of WMA using Sasobit in this study. However, additional tests at lower temperatures, along with a more complete thermal cracking analysis for specific environments of interest should be performed to get a more definitive answer regarding the effects of Sasobit on low temperature cracking.
    • Evaluation of the Overheight Detection System Effectiveness at Eklutna Bridge

      Lee, Ming; Moose, Dan (Alaska University Transportation Center, 2013-03)
      The Eklutna River/Glenn Highway bridge has sustained repeated impacts from overheight trucks. In 2006, ADOT&PF installed an overheight vehicle warning system. The system includes laser detectors, alarms, and message boards. Since installation, personnel have seen no new damage, and no sign that the alarm system has been triggered. Although this is good news, the particulars are a mystery: Is the system working? Is the presence of the equipment enough to deter drivers from gambling with a vehicle that might be over the height limit? Is it worth installing similar systems at other overpasses? This project is examining the bridge for any evidence of damage, and is fitting the system with a datalogger to record and video any events that trigger the warning system. Finally, just to be sure, researchers will test the system with (officially) overheight vehicles. Project results will help ADOT&PF determine if this system is functioning, and if a similar system installed at other bridges would be cost-effective.
    • Attenuation and Effectiveness of Triclopyr and 2, 4-D Along Alaska Highway Rights-of-Way in a Continental and a Coastal Subarctic Environment

      Barnes, David; Seefeldt, Steve (Alaska University Transportation Center, 2009-12)
      After more than 20 years of only mechanical brush cutting, ADOT&PF evaluated the use of herbicides to manage vegetation that interferes with line-of-sight and maintenance of the roadway. While researchers have investigated herbicide effectiveness and attenuation in more-temperate climates, little study has focused on cold regions. The purpose of this project was to measure the effectiveness and attenuation of two different selective auxin-type herbicides, 2, 4 dichlorophenoxyacetic acid (2,4-D), and 3,5,6-trichloro-2-pyridinyl acetic acid (triclopyr) in two subarctic climates; an extremely cold continental climate and a maritime climate. Conclusions from this study will aid the ADOT&PF in developing a plan for controlling vegetation along highway rights-of-way in Alaska.
    • Experimental Study of Various Techniques to Protect Ice-Rich Cut Slopes

      Li, Lin; McHattie, Robert; Zhang, Xiong; Zhang, Mingchu (Alaska University Transportation Center, 2014-08)
      Cut slopes are usually required to achieve roadway design grades in the ice-rich permafrost areas in Alaska. However, excavation and exposure of a cut slope destroy the existing thermal balance and result in degradation of ice-rich permafrost. Environmentally acceptable, legal, and economically viable solutions for ice-rich slope protection are still rare. Three potential thermal-erosion mitigation techniques were investigated. Four test sections (Section A: 1 ft wood chips, Section B: coconut blanket, Section C: coconut blanket + Tecco-mesh, and Section D: 1 ft crushed rock as a control section) were constructed at the Dalton Highway 9 Mile Hill during the period of April 17 through April 27, 2013. Temperature and moisture sensors were installed to monitor four test sections and evaluate the effectiveness of the different mitigation techniques. Also, a weather station was built to record climatic information at the test site by April 30, 2013. The filed monitoring period ended on November 11, 2014. No obvious erosion was observed in Sections A and B due to less ice content when compared with Sections C and D which failed one and a half months after construction. The performance of four techniques was discussed in detail.
    • Soil Stabilization Manual 2014 Update

      Hicks, R. Gary; Connor, Billy; McHattie, Robert (Alaska University Transportation Center, 2014-12)
      Soil Stabilization is used for a variety of activities including temporary wearing curses, working platforms, improving poor subgrade materials, upgrading marginal materials, dust control, and recycling old roads containing marginal materials. There are a number methods of stabilizing soils including modifying the gradation, the use of asphalt or cement stabilizers, geofiber stabilization and chemical stabilization. Selection of the method depends on the soil type, environment and application. This manual provide tools and guidance in the selection of the proper stabilization method and information on how to apply the method. A major portion of this manual is devoted to the use of stabilizing agents. The methods described here are considered best practices for Alaska.
    • Managing Dust on Unpaved Roads and Airports

      Barnes, David; Connor, Billy (Alaska University Transportation Center, 2014-10)
      Fugitive dust emanating from vehicle traffic on unpaved roads and runways can have significant impacts on safety, health, quality of life, and the cost of maintenance. Managing dust provides a means of reducing these impacts. Shearing forces created at the interface between the surface and vehicle tires produce dust on unpaved surfaces. The dust produced becomes airborne as a result of turbulence created by moving vehicles. Once airborne, different monitoring techniques can be used to assess the amount of fugitive dust produced and to measure the effectiveness of dust management strategies. Communities can manage dust by properly constructing and maintaining the unpaved surface, reducing vehicle speed on roads, and with the proper use of dust palliatives. The proper gradation of aggregate, the right profile, and good drainage are all necessary for reducing fugitive dust from unpaved roads and runways. Moreover, reducing vehicle speed on unpaved roads can dramatically reduce the amount of fugitive dust and result in longer periods between maintenance events. Several different types of palliatives are available for both managing dust on unpaved roads and runways. The choice of palliative is dependent on aggregate gradation, traffic amounts, climate, and location (remote or accessible).
    • High-Mast Light Poles Anchor Nut Loosening In Alaska - An Investigation Using Field Monitoring and Finite-Element Analysis

      Hamel, Scott; Hoisington, David (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, Pacific Northwest Transportation Consortium (PACTRANS), 2014)
    • Digital Dissemination Platform of Transportation Engineering Education Materials Founded in Adoption Research

      Perkins, Robert A. (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • A Platform for Proactive, Risk-Based Slope Asset Management, Phase II

      Cunningham, Keith; Olsen, Michael; Wartman, Joseph; Dunham, Lisa (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2015)
    • Estimating Future Flood Frequency and Magnitude in Basins Affected by Glacier Wastage

      Liljedahl, Anna; Debolskiy, Matvey; Youcha, Emily; Arendt, Anthony; Davis, Jennifer; Hock, Regine; Roth, Aurora; Wolken, Gabriel; Zhang, Jing (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2015)
    • Monitoring and Analysis of Frozen Debris Lobes, Phase I

      Darrow, Margaret M.; Daanen, Ronald P.; Simpson, Jocelyn M. (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2012)
    • Improving Passing Lane Safety and Efficiency for Alaska’s Rural Non‐divided Highways

      Dyre, Brian P.; Abdel-Rahim, Ahmed (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • Alaska Road Weather Project | Technical Performance Assessment Report | Fairbanks Field Demonstration 2013-2014

      Chapman, Mike; Linden, Seth; Burghardt, Crystal (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)