AK University Transportation Center Annual Report (TPD1112020)

Economical Analysis of Using Light-emitting Diode Technology for Alaska Streetlights (AUTC #207099)

Hsueh-Ming Wang (UAA)

Alaska’s winters provide few hours of sunlight during the day, driving up the costs to run municipal lighting systems. Around the nation, communities are exploring the use of LED technology for lighting streets to reduce energy use. For this reason, UAA researchers examined the costs and benefits of implementing LED streetlight technology in Anchorage.

Some researchers suggest that, under ideal conditions, an LED streetlight system might use 50% to 75% less energy than a traditional streetlight system, with a longer performance life. LED devices tend to be less fragile, switching on and off quickly without flickering. Additionally, while LED light systems normally overheat and burn out in temperate climates, companies suggest they can last five to ten times longer than fluorescents in colder climates. But, while LED technology could save millions, installing it may cost just as much. Converting an existing streetlight system to an LED system requires different circuitry and a different power supply, and installation costs alone could rise to several million dollars in a city like Anchorage.

UAA researchers wanted to determine the benefits versus the cost of using LED streetlights in some settings. They developed a hybrid self-sustainable LED lighting system with wind and solar energy and tested it on the Anchorage campus. Data collected from this new system indicated it has the potential to lead to energy independence from the energy grid system during summer months in Anchorage. Some of the research results may be patented in the near future. For some facilities, such as parking lots, this study’s results may save millions in annual maintenance costs while providing inexpensive energy to some facilities in Anchorage’s municipal system. In addition, providing safe lighting at a dramatically reduced cost could also provide lessons for other northern cities facing the same dilemma.

Long-range Transportation Forecasting for Greenhouse Gas Emission Estimation (AUTC #309042)

Ming Lee (UAF)

As warming trends cause environmental changes along the Pacific Rim, transportation planners are weighing the long-term impacts that may threaten existing infrastructure. For example, studies have linked greenhouse gas (GHG) emissions to changes in the earth’s climate.

Increases in demand for freight transportation, personal vehicles, and changes in traffic operations all impact production of GHG. Urban planners need a reliable travel-demand forecasting model that help them predict and address how these components affect our ability to reduce or mitigate GHG emissions.

This project studied the Fairbanks Metropolitan Area Transportation System to determine if this modeling method could be used to estimate GHG emissions. Outputs from the FMATS model served as inputs for air quality models used by the EPA, which the agency uses to confirm air quality compliance. Some of these require traffic volume forecasts with spatial and temporal details that exceed what the current travel-demand models can produce.

This study examined inefficiencies of the models and developed effective methods of addressing them. Researchers validated, calibrated, and observed current data from the improved models, and applied forecasting scenarios to demonstrate the capability of the models and their ability to successfully predict the effectiveness of GHG emission reduction for a proposed transportation scenario.

Developing Ambient PM2.5 Management Strategies (AUTC #107004)

Ron Johnson and Tomas Marsik (UAF)

Research on air quality problems in Fairbanks, Alaska is helping identify transportation management strategies that reduce air pollution and traffic while improving public safety.

Collection of electronic data proved successful in this closed-loop road construction study. The tracked events were pickup and delivery of asphalt, with round-trip and time on station for loading; these key variables helped describe the initial intent of this study. RFID technology proved successful in tracking dump trucks from the loading plant to a paver location on a highway project. The average round-trip time was 1 hour and 4 minutes. The final report is under review by the funding agency.

Feasibility of Electric Cars in Cold Regions (AUTC #RR08.05)

Jing Zhang (UAF)

Converting the Fairbanks Metropolitan Area Transportation System (FMATS) Travel-demand Forecasting Model from QRS II to TransCAD (AUTC #MISC7)

Ming  Lee (UAF)

For transportation asset managers, it’s always good to anticipate a crisis long before it becomes one.

After the 2000 Census designated Fairbanks, Alaska, as an “urbanized area,” officials realized they would soon need to conform to the Federal Highway Administration’s (FHWA) requirement that such areas form a Metropolitan Planning Organization (MPO). MPOs manage travel planning and federal highway funding, and typically use a travel-demand model to assess current travel demands and to anticipate changes in an area’s transportation needs. Providing the new MPO with a suitable modeling system required assessing a variety of available information, such as air quality standards and traffic mapping, and integrating this information with new, more advanced software. This new system allows the MPO to forecast population, employment, travel, and environmental trends to anticipate problems and mitigate them before they become crises.

Performance Analysis of the Dowling Multi-Lane Roundabouts (AUTC #RR08.08)

Ming Lee (UAF)

Although hardly new to the Lower-48 states, multi-lane roundabouts are relatively new to Alaska’s urban areas, but they are becoming an increasingly useful tool for shaping effective traffic operations.

Alaska’s first multi-lane roundabouts came to Anchorage’s Dowling Road/ Seward Highway interchange in 2004. They serve as junctions for commuters accessing the Seward Highway, but as Anchorage’s traffic grows, the Dowling roundabouts are becoming more congested. To date, the roundabouts are operating at or near capacity, with longer lines at their entrances during peak traffic hours.

This research project examined the performance of multi-lane roundabouts and how drivers use them. Analysis showed that unbalanced flow patterns caused high circulating flow in front of one roundabout, leading to longer lines. This high circulating flow has resulted in lower capacity and longer delays. Researchers also found that accident rates and pedestrian dangers have increased in the past two years. Modeled traffic flow patterns for several possible alternatives suggested that reducing the eastbound flow rate (think of it as “upstream” of the roundabout) by 70% of the original flow could result in an acceptable level of delay and line length at the eastbound approach to the west roundabout.

A study like this not only helps planning engineering in Anchorage, but also gives agencies statewide better ideas about how to design future multi- lane roundabouts in ways that will provide safe and efficient travel. To learn more about this project, see the feature story in AUTC newsletter Volume 4, Number 1 on our web site.

New Structural Integrity Projects

Current research will optimize this new design to improve energy displacement capacity and ductility in bridge and marine structure design, as well as investigate additional connection designs proposed by ADOT&PF engineers. Researchers have conducted three seismic tests, and plan to complete follow-up tests in coming months. The research will result in a series of design recommendations to ensure that bridges withstand Alaska’s seismic activity levels. The team’s research will help improve the design and performance of steel bridges and marine structures containing similar connections. It may extend bridge service life, reduce maintenance costs, and improve safety as a result.

To learn more about this research, see AUTC newsletter Volume 4, Number 2, at our web site.

Effect of Load History on Performance Limit States of Bridge Columns (AUTC #410002)

Mervyn J. Kowalsky (NCSU), Utpal Dutta (UAA), and Andrew Metzger (UAF)

Transportation engineers and bridge designers are concerned about Alaska’s past history of earthquakes and other seismic activity, and the unseen effects it may have upon today’s bridges and other concrete structures. Addressing this issue, a collaborative team will examine how current studies evaluate the amount of strain that can be put upon a structure before it breaks.

This project investigates the impact of seismic loading history on the design of reinforced concrete bridge columns typically used in Alaska. Strain limit states are used by researchers when calculating the amount of stress that can be put upon a structure like a concrete bridge column, or a steel reinforcement beam. However, structural engineers currently use concrete and steel strain limit states in seismic design that only have minimal experimental or theoretical basis. This team hopes to propose strain limit states that account for seismic loading histories specific to Alaska, and to relate these proposed strain limits to displacement limits used in testing designs for the state’s bridges.

The team will conduct a combination of both analytical and experimental studies. These tests will include both frame-type and fiber-based analysis using ground motions, and the results will guide the initial selection of specimen design variables. Conducting this research will involve nine tests on full-scale circular bridge columns, which will be subjected to load histories with varying characteristics, but typical of those experienced in Alaska.

The research team will provide ADOT&PF engineers with tools to refine bridge designs, optimizing for regional seismicity and ensuring that bridges in Alaska remain safe in major earthquakes and serviceable in smaller earthquakes. This advancement, in turn, may improve the reliability of bridges, decrease maintenance costs, and improve safety. To date, researchers have designed and constructed six additional test units, and have begun refining fiber-based models as they work to predict accurate strain distributions in the test columns. They will soon begin seismic testing on the six test units, parametric studies, and test-data analysis.

Selecting Preservatives for Marine Structural Timbers in Herring Spawning Areas (AUTC #410037)

Robert A. Perkins (UAF)

Marine harbors and docking facilities are a central piece of Alaska’s commerce, trade, and tourism industries, and key travel conduits in vast regions of the state that lack connected inland roads. Alaska marine harbors use wood for many structures that come in contact with salt water, including piles, floats, and docks, because it is economical to buy and maintain.

However, wood immersed in salt water is prone to attack by marine borers—various types of marine invertebrates that can destroy a wood structure in only a few years. Only two wood preservatives are currently recommended for use in Alaska’s waters—ACZA (ammoniacal copper zinc arsenate) and creosote, both of which have side-effects.

ACZA is a water-based preservative that leaches copper, which is toxic to both marine invertebrates and other species, into the marine environment. Creosote, an oil-based preservative made from coal tar, leaches hydrocarbon chemicals into the water. While some research has been conducted on these chemicals, we still have more to learn. For example, some research indicates that copper leaching from ACZA is slight after a year or so, while creosote leaches PAH at a declining rate over time, but is still measurable after many years. Previous researchers have had difficulty narrowing their search to just these two preservatives because harbors are frequently contaminated with many other chemicals, so determining how the wood preservatives alone impact marine life over time is difficult.

Perkins will test the toxicity of marine structural materials to herring eggs under a variety of conditions common in Alaska marine waters, focusing on Southeast Alaska. The study will also compare the durability of creosote- versus ACZA-treated marine timbers under comparable climatic and service conditions.

This project aims to provide relevant information to ADOT&PF to improve its selection of wood structural materials in the marine environment, especially the selection of wood-preserving methods. Its results may help structural engineers and other marine specialists make better-informed choices about wood preservatives that are both economical and environmentally sound. Perkins has performed toxicity tests on thousands of herring eggs and larvae using creosote marine timbers; over the next year, he will examine chemistry data and take samples near existing creosote structures.

Shake Table Experiments of Bridge Foundations in Liquefied Soils: An International Collaboration (AUTC #410015)

Zhaohui “Joey” Yang (UAA)

Chinese and American engineers are no strangers to the lingering destruction caused by earthquakes. This project brings together expertise from both nations to examine how earthquake-associated liquefaction threatens bridge foundations.

Soil liquefaction occurs when stress, usually caused by an earthquake or shaking, causes soil to act more like a liquid, losing stiffness and strength. An outgrowth of another AUTC project, this research will benefit from collaboration with Professor Yulin Yang, an engineer at China’s University of Science and Technology, Beijing. Yang is interested in liquefaction-induced geotechnical engineering problems in cold regions and is willing to share the cost of two large-scale shake table tests, which makes it feasible to integrate physical testing with AUTC’s ongoing simulation project.

Liquefaction and associated ground failures have been common in major earthquakes across Alaska, causing extensive infrastructure damage. Lateral spreading—subsurface soil shifts that often rip apart fixed infrastructure above ground—is particularly damaging if a non-liquefiable crust rides on top of liquefied soil during an earthquake. This project aims to examine liquefaction-induced ground failures and their consequences for highway bridge substructures, and also to validate the results of computer modeling.

A key area of interest is how frozen ground layers behave. The physical properties of a crust of frozen ground change drastically in winter. Stiffness and strength increases, while permeability decreases. The impact on a bridge foundation by a frozen ground crust resting on a liquefied soil layer and the loads generated during a winter earthquake are unknown.

The knowledge gained from this project will lead to improvements in seismic design of highway bridge foundations in Alaska and in other northern regions with seismic activity. The research aims to eventually reduce the tremendous costs and safety risks created by large-scale destruction of key infrastructure during an earthquake. The project also represents a fruitful partnership between two nations that are increasingly dependent upon infrastructure innovations to further their commercial, transportation, and domestic energy needs.

The Response of Pile-Guided Floats Subjected to Dynamic Loading (AUTC Affiliate Project)

Andrew Metzger (UAF)

Pile-guided floats are structures, such as piers or docks, that boats and other sea vessels attach themselves to so that a ship can move up and down as water levels vary. Pile-guided floats provide an alternative to stationary dock structures.

ADOT&PF is considering using floating piers at certain stops along the Alaska Marine Highway System (AMHS). A potential design calls for the floats to be held in place by guide-piles that allow vertical rise and fall during tidal changes. The floats also undergo other varying forces, such as wind-generated waves and the weight of cargo and people as ships load and unload at the dock. There is little design information available concerning how this dynamic loading will affect the floats.

This project is developing a rational basis for estimating the dynamic response of floating pile-guided structures. Researchers will develop a model for two different systems. Both models will include functions that represent wave action and vessel loading over time. At the project’s end, AMHS and ADOT&PF will have a validated model and a ready-to-implement tool capable of providing any engineer with the necessary insight into good design criteria for both floats and guide-piles.

Frozen Soil Lateral Resistance for the Seismic Design of Highway Bridge Foundations (AUTC #510021)

Zhaohui “Joey” Yang (UAA)

With recent seismic activity and earthquakes in Alaska and throughout the Pacific Rim, seismic design is becoming an increasingly important public safety concern for highway bridge designers. Hoping to generate knowledge that can improve the seismic design of highway bridges in Alaska, UAA researchers tested a fixity-depth approach and a lateral-resistance (p-y) approach in seismic bridge design.

Currently, ADOT&PF utilizes a soil lateral-resistance approach in the seismic design of bridge pile foundations. Knowledge about lateral resistance of frozen soils, particularly seasonally frozen soils at shallow depths, can help improve pile foundation design in cold regions. Researchers Joey Yang and Anthony Paris are conducting laboratory experiments to examine key mechanical parameters for the frozen soils used to construct the p-y curve for modeling frozen soils.

Although studies have been conducted on the mechanical properties of frozen soils, many of these were based on remolded, artificially frozen soil samples, which do not necessarily behave the same as soils in the field. Similarly, few stress-strain behavior studies have focused on small strains (rather than catastrophic failures), and few have made use of naturally frozen samples (as opposed to samples frozen in the lab).

Yang and Paris hope to fill this knowledge gap by providing key frozen soil parameters for typical Alaska soils. According to Yang and Paris, these soil parameters are necessary for predicting the formation and location of plastic hinges and internal loads in bridge pilings embedded in frozen soils during seismic loading. As they develop more information, this team will hold a workshop for bridge design engineers to discuss their findings and how to apply them in the seismic design of bridges.

Together AUTC, ADOT&PF and Washington State DOT are funding a comprehensive study of marine ferry docking structures. The partnership benefits ferry systems that link traffic between Alaska, British Columbia, and Washington.

Load Environment of Washington State Ferry and Alaska Marine Highway Landings (AUTC #309001)

Andrew Metzger (UAF)

As pacific commerce and travel grow, docking structures become more important from both an economic and public safety standpoint—especially as new shipping lanes are created by melting trends in northern waters.

Anybody riding a ferry wants it to dock safely—and for port managers, having passengers and goods in the water is never a good thing. This project aims to mitigate uncertainty and assumptions about load demands on ferry terminal structures, specifically ferry landing structures. The project will provide information needed to safely and efficiently design ferry facilities while improving structural design criteria and procedures.

For Alaska Marine Highway System (AMHS) facilities, loads imposed on dolphin structures and mooring lines are of most concern. Marine facilities that rise above the water but are not connected to shore, Dolphin structures are used to extend piers, serve as ship cushions, or display information, such as directions or warning lights. Mooring lines are the (often large) rope ties that connect ships to docks. The loads placed upon these structures can determine if a ship docks successfully or not, and how well it will resist currents, waves, and other forces that might damage it or send it adrift.

Due to a lack of information about the magnitude of these loads or how they may be determined, AMHS engineers are forced to make design assumptions. The Washington State Ferry System (WSFS) also confronts these uncertainties, specifically in the design of wing wall structures that accept vessels during loading/unloading of passengers and vehicles. Wing walls are wall structures that are linked to larger-sized walls or structures next to them. While the structures used by AMHS and WSFS have fundamental differences, the metrics needed to determine appropriate design criteria are the same, and the instruments used to monitor these facilities are also similar.

These similarities present an opportunity for a cost-sharing project in which ADOT&PF and Washington State DOT are able to leverage research funding and benefit from a much more comprehensive project than either might be able to support individually. The partnership makes sense, as both states operate ferry systems linking traffic between Alaska, British Columbia, and Washington.

To achieve its goals, the project team will acquire a robust statistical sample of the metrics needed to define the design criteria. The data will be gathered by monitoring in-service facilities like the AMHS terminal at Auke Bay near Juneau, Alaska, and the WSF Seattle terminal in Washington. So far, the team has completed fieldwork in Auke Bay and Seattle, and has presented portions of its research at the 2011 Coastal Engineering Practice Conference.

For more information about this project, see the feature story in our newsletter (Volume 5, Number 1) posted on the AUTC website.

Smart FRP Composite Sandwich Bridge Decks in Cold Regions (AUTC #107018)

Pizhong Qiao, Washington State University (WSU)

What if every time a bridge on a lonely road got icy, it automatically notified engineers or maintenance crews to begin ice-control safety measures? What if a bridge could tell someone every time an overloaded truck hit the decking, or when the trusses under it began to weaken? This kind of structural self-monitoring is closer to becoming a possibility at the completion of this research project.

A partnership between WSU, UAF, and Kansas Structural Composites, Inc., this project made the first steps to develop, manufacture, test, and implement Smart Honeycomb Fiber-Reinforced Polymer (S-FRP) sandwich materials.

This technology integrates advanced composite materials with sensors and actuators, allowing a bridge to alert engineers to surface and structural problems as they occur. Researchers expect that the system can quicken engineers’ reaction time, reduce excessive maintenance costs, and prevent significant safety risks before they occur.

Researchers tested an S-FRP sandwich deck panel, evaluated several S-FRP sandwich beams in cold temperatures, and developed effective structural- health monitoring strategies. They developed dynamic tests for the deck panel technology with and without damage, and created structural-health monitoring strategies for cold temperature exposures.

This combined experimental, theoretical, and numerical approach supplied new data on new techniques for structural-health monitoring and damage identification of thick sandwich deck panels. Results showed that wireless communication technologies may allow the developed structural- health monitoring strategies to remotely monitor and assess the structural integrity of sandwich bridge decks in cold regions. For Alaska bridges—many of which are located in isolated, remote areas with extreme weather—this innovation is a major step forward in terms of cost-effective maintenance and public safety preservation.

Seismic Performance of Bridge Foundations in Liquefiable Soils (AUTC #309010)

Zhaohui “Joey” Yang (UAA)

What physically happens to a bridge foundation during an earthquake? And what if the bridge foundation sits on a frozen crust of ground resting upon a layer of liquefiable soil, which behaves as a liquid during an earthquake? How can engineers make bridges strong enough to withstand these natural forces? Serious safety questions like these are unique to arctic areas such as Alaska, but no seismic analysis guidelines exist to explain how frozen-ground crust affects bridge foundations at a liquefiable site.

Addressing this knowledge gap, this project offered the first explanation of how bridge foundations withstand stress loads imposed on them by a frozen crust disturbed by liquefaction and lateral spreading. Study results are improving how engineers design arctic highway bridge foundations in areas threatened by seismic activity. Better seismic performance of Alaska’s bridges will increase transportation safety and reduce maintenance and reconstruction costs following a seismic event.

Researchers began this work by constructing a sophisticated model capable of simulating soil liquefaction and testing it. They used the model to simulate how a typical Alaska bridge pile foundation—one embedded in liquefiable soils under a frozen or unfrozen crust layer—would respond to seismic activity. Preliminary results showed that bridge pile was very sensitive to crust conditions. When the crust froze, for example the bridge pile’s internal forces changed by roughly 50%, demonstrating a greater need for further research into this phenomenon.

Because simply relying upon numerical simulations seemed insufficient for this work, researchers wanted to supplement it with an experimental component. Interestingly, this experimental component involved large-scale shake-table experiments conducted in collaboration with counterparts at China’s University of Science and Technology, Beijing. Test data, including soil responses and pile internal forces, were used to validate the computer simulation results.

What if a  bridge could tell someone every time an overloaded truck hit the decking, or when the trusses under it began to weaken? This kind of structural self-monitoring has become a possibility thanks to a partnership between Washington State University, Kansas Structural Composites, Inc., and AUTC.

Iowa State University demonstrated how cold temperatures impact the behavior of reinforced concrete and—most important—how the soils, the foundation, and the structure interact. Their findings contributed to a new design methodology tailored to seismic regions where seasonal freezing is common.

surface applications

From dust-control measures to pavement preservation, surface application research is widely applied across numerous transportation mediums.

For example, David Barnes’ diverse work on dust-reduction palliatives has entailed research on unpaved roads in both urban and rural settings, and also addresses rural runways. For local stakeholders, this work provides measures to improve air quality, enhance transportation services, and boost their quality of life.

Still central to all of AUTC’s work as a national leader in cold region transportation research, however, is the concern of preserving construction materials in some of the world’s most unforgiving climates. Jenny Liu’s numerous projects on pavement preservation, for instance, address a range of issues tied to more durable, long-lasting, and cost-efficient materials for cold-region transportation surfaces.

For road and repair managers as well as engineers, this area of research is helping create more durable, less expensive, and longer lasting roads, bridges, and runways.

New Surface Applications Projects

Understanding and Mitigating Effects of Chloride Deicer Exposure on Concrete (AUTC #510003)

Xianming Shi (Montana State University-Bozeman) and Billy Connor (UAF)

Relying on chloride deicers, The U.S.A. spends approximately $2.3 billion annually to keep highways free of snow and ice. Exacerbating these expenses, the associated corrosion and environmental impacts add at least $5 billion. Looking at the effects of chloride deicer exposure on concrete, UAF AUTC director Billy Connor teamed up with Xianming Shi,director of the WTI Corrosion & Sustainable Infrastructure Lab at Montana State University-Bozeman (MSU), to lead a project that will minimize the costs of concrete damage and repair caused by deicer exposure.

This work will link laboratory testing of deicer effects on concrete with actual field exposure and allow DOTs to predict and reduce levels of chloride-related infrastructure damage. Researchers will work with both ADOT&PF and the Oregon Department of Transportation (ODOT) to investigate how each entity uses chloride deicers, the effects of that use, and the best ways to mitigate those effects in Oregon and Alaska. Using internal surveys, laboratory research, and field investigations, researchers will advance the relevant knowledge base related to deicer/concrete interactions to improve long-range infrastructure repair and replacement planning and develop mitigation strategies.

Above, Laboratory set-up for simple performance testing of warm mix asphalt samples, part of Juanyu Liu’s pavement preservation program. In the foreground is a pavement sample that has been subjected to dynamic modulus testing.

Opposite, graduate student Natalia Kulchitskaya reviews data collected as part of this series of tests.

The team will offer guidance on how to best mitigate negative impacts of chloride deicers on concrete and enhance concrete durability and sustainability, which will boost infrastructure service life. This guidance can translate into substantial cost savings and environmental benefits while enhancing the reliability of the transportation infrastructure in cold-climate states.

Develop Locally Sourced Salt Brine Additive for Anti-icing (AUTC #510006)

Xianming Shi (MSU) and Juanyu “Jenny” Liu (UAF)

A research partnership between Montana and Alaska may bring considerable cost savings and safety improvements to Alaska’s roads. Xianming Shi from MSU’s Western Transportation Institute (WTI) and Jenny Liu (AUTC) partnered to investigate whether local agricultural or distillery by-products can replace high-cost proprietary products that enhance anti- icing operations on Alaska roads.

Using a literature review, agency surveys, laboratory investigation, and follow-up field tests, researchers will develop and test locally sourced salt brine additives to determine whether they are suitable for anti-icing during winter maintenance in Alaska. This determination will help improve traveler and commercial safety and mobility while reducing corrosion and environmental impacts. The project will also give ADOT&PF more options for their snow and ice control while promoting sustainable, cost-effective winter road service. Moreover, in a time of widespread fiscal belt-tightening, this work allows state winter road maintenance budgets to cover more roads or more frequent anti-icing activities.

Beyond reducing Alaska’s winter road maintenance costs, this research may also boost local economic growth by helping build a new market for glycerol—the principal by-product of biodiesel production. The bio-based local materials may also be useful for dust suppression and soil stabilization, adding to the potential benefits of this research.

Economic Impact of Fines in Unbound Pavement Layers (AUTC# 510012)

Juanyu “Jenny” Liu (UAF)

In Alaska’s spring months, excess water thawing underneath road pavement weakens roads and other transportation infrastructure, causing great expense and inconvenience for private and commercial motorists. This project examines how the fines (P200) in base materials affect frost susceptibility and support for vehicular loads during the spring thaw. Realizing the variation in critical excess fines content, Liu’s team is also evaluating the financial impact of using allowable fines in the unbound pavement layers and will identify critical excess fines contents (that is, threshold fines content) allowed in the typical Alaska unbound base courses.

Expanding upon a recent UAF study, Liu is investigating the impact of fines content on resilient modulus reduction of base courses during thawing when the base course material is frozen under different temperature gradients and with limited water access. To do this, Liu and her team will simulate a closed water system by collecting soil specimens with different initial moisture and fines contents and freezing them in the frost heave cell with no access to water. Her team will then test resilient moduli of soil specimens under different subfreezing temperatures and after a freeze-thaw cycle under both undrained and drained conditions. The testing will provide recommendations to determine the situations when  ADOT&PF can relax stabilized basepolicies and when builders might reduce costs by allowing excess fines in the base layers for highway construction.

Impact of Embedded Carbon Fiber Heating Panel on the Structural/ Mechanical Performance of Roadway Pavement (AUTC #510022)

Zhaohui “Joey” Yang (UAA)

Cold regions suffer serious transportation system safety problems in the winter months. Southcentral Alaska—Anchorage in particular—is susceptible to a large number of icing events due to frequent freeze/thaw cycles in the winter season. This creates ice on sidewalks, pavement, and bridge decks that poses a significant safety risk to travelers of all kinds. Black ice, a thin shiny layer of ice with a slick surface, is of particular concern because it is nearly invisible to drivers, pilots, and pedestrians.

This collaborative research project is finding more cost-effective and sustainable deicing solutions to benefit a wide variety of transportation infrastructure users. UAA is partnering with the University of Houston to test a technology based on carbon fiber tape (CFT) in hopes of offering an environmentally-friendly, anti-corrosive, cost-effective deicing strategy that can improve transportation safety. This new deicing technology is potentially applicable to bridge decks, ice-susceptible road sections, airport runways, street crossings, and high-use urban sidewalks in cold regions.

A series of deicing and anti-icing experiments showed considerable cost reduction compared to other electrical resistance heating type technologies. Researchers found that the new technology demonstrates excellent deicing capability and shows great potential for application in the transportation industry.

Continued lab and field work will address several other issues including: heating panel impact on pavement/bridge deck structural integrity, effects of coupled thermal and freeze-thaw cycling on pavement mechanical properties, and the impact of an electromagnetic field on steel reinforcement corrosion in bridge/pavement decks. Findings from the sidewalk test section and laboratory tests will be incorporated into a sidewalk constructed on the UAA campus to evaluate the field performance of this new technology.

Yang’s series of deicing and anti-icing experiments showed a considerable cost reduction for deicing and anti-icing compared to other electrical resistance heating type technologies.

Field-Evaluating Crack Sealing of Asphalt Concrete Pavements in Alaska (AUTC #510005)

Juanyu “Jenny” Liu (UAF)

For years, routine sealing of cracks in asphalt concrete (AC) has cost the state of Alaska millions of dollars annually. Without new technology to eliminate the cracking, sealing and minor patching will continue to be a major expense for ADOT&PF. This project aims to find possible cost-effective improvements to existing crack-sealing methods.

Some research suggests it may be possible to ignore cracks entirely, under certain circumstances, with no negative effects. Hoping to devise more economically sound approaches to road repair, Liu is working with field researchers to determine where sealing is necessary and where it is not. The team will also determine the effectiveness of several different repair treatments for major transverse cracks.

Ultimately, the team will provide recommendations for saving a significant portion of the maintenance and operations funds now spent on crack sealing and minor patching of major transverse cracks. The research will provide ADOT&PF with research findings that the agency can easily integrate into its Departmental Guidelines for Pavement Preservation Treatments in Alaska.

Longevity Analysis of Dust Control Palliatives (AUTC #510019)

David L. Barnes (UAF)

Rural Alaska’s residents and local stakeholders are looking for cost-effective methods to reduce road and airfield dust. However, they remain concerned about the longevity and performance of different types of dust- control products used in unpaved regional transportation systems.

Headed by researcher David Barnes of the Water & Environmental Research Center (WERC) at UAF, this project uses new instruments and methods to conduct field-based measurements of dust-control palliative performance and longevity in rural communities. Barnes’ project is supported by Midwest Industrial Supply Inc., manufacturer of EK35—one of two palliatives tested in the study. The other palliative, Durosoil, is manufactured by Soilworks® LLC. ADOT&PF applied these products to several airfields and roads in Alaska, and researchers are monitoring their effectiveness over time.

This study will help community leaders as well as agencies like ADOT&PF and the Alaska Department of Environmental Conservation (ADEC) better understand the longevity, performance, and potential cost-effectiveness of these products. Barnes’ team will use laboratory-based testing to better understand why some applications of the same product do not perform as well as others. If this testing correlates with field-based measurements, researchers may be able to predict the possible performance of a palliative prior to its application, allowing for adjustments in application rates if necessary, as well as more cost-effective implementation. In addition, by enhancing knowledge about the performance of these two palliatives, this project may enable better-informed quality of life decisions in rural areas.

Rapid Determination of Unsaturated Moisture Diffusivity for Soils during Frost Heave (AUTC #510017)

Xiong Zhang, Gang Cheng (UAF), and Rifat Bulut, Oklahoma State University (OSU)

Frost heave and annual thaw cycles pose great risks to transportation infrastructure, raising maintenance costs and undermining transportation service and safety. Unsaturated soil mechanics and unsaturated water transmission are key factors in understanding frost heave and thaw weakening problems typical in northern regions. While significant progress has been made in unsaturated soil mechanics in the past two decades, the field has yet to apply practical solutions to these problems.

This new research partnership, funded in part by the ADOT&PF and by the Oklahoma Transportation Center (OkTC), is developing a unified, simple and practical testing method to measure unsaturated soil moisture diffusivity coefficients; both the drying and wetting diffusivity coefficients are key pieces of soil mechanics research. The new method significantly reduces the time and effort required to measure the drying and wetting unsaturated soil moisture parameters by exposing the cylindrical soil specimens to drying and wetting cycles.

The project aims to implement the most recent advances made in unsaturated soil mechanics to investigate the frost heave problem, utilizing equipment development, laboratory testing, model development, and numerical simulation. Greater understanding of unsaturated soil mechanics may greatly reduce the operations and maintenance budget for ADOT&PF by addressing frost heave and weakening problems and offering more efficient prevention and maintenance procedures.

Ongoing  Surface  Application Projects

Accelerated Degradation and Durability of Concrete in Cold Climates (AUTC #410029)

Pizhong Qiao (WSU) and Juanyu “Jenny” Liu (UAF)

Cold weather climates degrade concrete, causing fractures and erosion. For engineers, this means more costly maintenance and risks to public safety caused by hazardous roadways and other surfaces. In Alaska and other cold regions, concrete degradation, specifically the break down of aggregate materials within the concrete mix, is the central concern.

Aggregate materials are a major component of concrete. Typically, cement mix is blended with filler like rocks and stones of various sizes to make it more durable and cost-effective as a surface application. Cement mix is the most expensive component of concrete, so the optimal amount of aggregate makes a less expensive and more durable mix. For that reason, typical cement mixes contain as much as 60% to 80% aggregate to enhance longevity and cut costs. Extensive studies have been conducted on the design of concrete mix and the composition of cement materials to improve performance and durability.

Cement mix is the most expensive component of concrete, so the right amount of aggregate is crucial to producing a less expensive and more durable mix. But what is the right amount? Together UAF and WSU are looking for ways to improve concrete aggregate testing in cold environments.

A collaboration between UAF and WSU researchers, this project is looking for ways to improve how concrete aggregate is tested in cold environments. The team will apply a promising testing protocol for long term concrete performance. Using damage mechanics modeling, they will also evaluate how damage accumulates in concrete and how concrete remains durable at cold temperatures. Their central aim in this study is to develop specifications on performance criteria and service life predictions, and to provide guidelines for ADOT&PF engineers who evaluate concrete performance and safety. These outcomes will improve concrete construction and transportation infrastructure maintenance in cold climates.

Testing and Screening Surfacing Materials for Alaska’s Yukon River Bridge (AUTC #410008)

J. Leroy Hulsey (UAF)

The Yukon River Bridge is a formidable and somewhat iconic structure in Alaska. The story of its construction efforts in the 1970th’s has become part of Alaska’s state heritage. Also known as the E.L. Patton Bridge, it carries the two-lane Dalton Highway and the trans-Alaska oil pipeline across the Yukon River at a 6% grade. It is 30 feet wide, more than 2200 feet long, and has 6 spans. It was designed to withstand -60F temperatures, the force of huge ice loads on the river, heavy trucks hauling supplies to the oil fields, the oil pipeline, and, in the future, a gas line.

Over 30 years, the timber decking has been replaced several times—in 1981, 1992, 1999, and 2007. The trees that produced the original decking were massive old-growth firs, strong and close-grained. Subsequent decking has come from younger trees, which produce softer wood. As timber quality has decreased, time between replacements has also decreased, and material prices have increased.

To learn more about this project, see AUTC newsletter Number 1, Volume 1.

Using the Micro-Deval Test to Assess Alaska Aggregates (AUTC #410009)

Juanyu “Jenny” Liu (UAF)

Choosing the right material is half the battle in building Alaska’s roads. The extreme conditions typical to cold regions require a durable aggregate that is both abrasion-resistant and freeze-thaw resistant. ADOT&PF wanted to know if its engineers are using the most effective and accurate methods available to select the right aggregate to build the state’s highways.

To evaluate surface abrasion and degradation values, Alaska currently uses a testing method known as “Method 313,” or the Washington Degradation Test. This project is examining an alternate method that may prove safer and less costly, if its results are replicable and correlate with field performance. One method, the Micro-Deval test, involves putting aggregate materials in a tumbling steel drum with water and steel balls to measure how they degrade. The test is relatively easy, safe, and less costly to perform than traditional testing methods. It is also suitable for smaller equipment, requires smaller sample quantities, and uses a simple procedure.

Liu’s team has completed and summarized their aggregate testing results, and will soon focus on additional aggregate testing methods, which use sand equivalents and a hydrometer.

Characterization of Alaska Hot Mix Asphalt Mixtures with a Simple Performance Tester (AUTC #410020)

Juanyu “Jenny” Liu (UAF)

To make pavement more durable—thus safer and more cost effective—engineers are striving to better understand the properties of hot mix asphalt (HMA). Road builders are expressing a growing need for mechanistic flexible pavement design and for more reliable design procedures; both require a more accurate understanding of different HMA properties.

This study is aiding this process by giving engineers a better idea of which HMA mixtures are more durable and more suitable to Alaska’s demanding climate. The research team is developing a catalog of dynamic modulus values for mixtures typically used in Alaska. Dynamic modulus values measure the ratio of stress to strain that a material can withstand. Researchers are also investigating the correlations between simple performance test results and HMA lab performance, to gain a full understanding of specific HMA properties. The results will give ADOT&PF engineers practical information about how Alaska HMA mixtures respond to the new test procedures, and how using these mixtures will affect current flexible-pavement design methods.

Research must identify a material suitable for bridge decking that will last more than 15 years in Alaska’s harsh climate. This will mean future savings to the ADOT&PF in the millions of dollars by reducing necessary maintenance and extending surface service life.

So far, the project has manufactured mixture specimens and coordinated testing activities through counterparts at the University of Tennessee to begin analyzing data. In the coming months, the team will continue to fabricate specimens, verify mixture design, and conduct further tests to conclude the project.

Construction Dust Amelioration (AUTC #RR10.03)

Robert A. Perkins (UAF)

Dust produced on seasonal road construction sites in Alaska is both a traffic safety and public health concern. Dust emanating from unpaved road surfaces during construction severely reduces visibility, impacting stopping sight distance for drivers. When the dust is stirred by wind or traffic, it also contributes to the local burden of small particulates that pollute air quality (also known as PM 2.5). This study is examining a variety of factors dealing with the use of dust-control palliatives. Experts believe applying a dust-control palliative like calcium chloride, Enviroclean, Durasoil, or EK35 to unpaved surfaces during road construction will solve the dust problem. This research is determining the type of palliative to use, and when, how often, and in what concentration it should be applied. The project is looking specifically at several factors, including the amount and size of the dust particles, the time the surface is to remain unpaved, the makeup of the unpaved road surface, local environmental conditions, and the palliative’s cost and availability.

The project is especially valuable because measurement systems used in other states involve special equipment and/or certification of observers, neither of which may be practical in Alaska with its remote locations and short construction season.

Perkins’ research will help ADOT&PF to develop safer, more cost-effective, and efficient techniques for short- term dust suppression.

Performance of Dust Palliatives on Unpaved Roads in Rural Alaska (AUTC #410036)

David L. Barnes (UAF)

One of several dust-reduction projects underway at AUTC, this project is assessing the longevity of different palliatives applied to rural Alaska roads over two summer seasons.

Researchers are collecting data using the UAF’s dust monitoring system (DUSTM). Created and assembled by Project PI Barnes and fellow researchers at the UAF Civil and Environmental Engineering Department, DUSTM is a portable dust monitoring device that can be attached to the rear of an ATV, and is compact enough to be transported in a small airplane. It measures the amount of airborne or loftable dust that is spread on a village street or unpaved roadway, and can calculate reductions or increases in dust over time. The research team is applying and monitoring palliatives in five different sections of Alaska roads: three in rural villages and two in the towns of North Pole and Point McKenzie.

This project is co-funded by AUTC and the Alaska Department of Environmental Conservation; ADEC seeks to compare associated dust concentrations measurements from DUSTM with those collected by their own stationary monitors. Correlation between the two data sources will determine how much of the measured fugitive dust is from a controllable emission source, and how much is from uncontrollable sources. Both for public health and cost-effectiveness considerations, researchers want to know how much fugitive dust must be suppressed to meet regulatory standards. Researchers will use this information to help local communities plan the use of dust-control palliatives.

Application of a Nontraditional Soil Stabilization Technology: Lab Testing of Geofibers and Synthetic Fluid (AUTC #207117)

Billy Connor (UAF)

Gravel in essentially nonexistent in Western Alaska. Whenever gravel is needed for infrastructure such as a road or a runway, it is imported at a cost exceeding $200/ per cubic yard. These costs can be dramatically reduced if local soils can be made usable in place of imported gravel.

This project, funded by ADOT&PF and AUTC, is investigating a new technique for using geofibers and a synthetic fluid to stabilize loose, sandy, and silty soils typical of western Alaska. Lab tests measured how well these new materials might improve poor foundation soils. Results showed that fibers can double or triple the strength of the soil. While the addition of synthetic fluids adds some strength, their primary function is to reduce moisture sensitivity of the fine-grained material. However, a two-part chemical additive has proven to increase the strength of sands, silts and clays at a lower cost than imported gravel. This project is the basis for a field application of these new materials; see below to learn more.

Application of a Nontraditional Soil Stabilization Technology: Use of Geofibers and Synthetic Fluid in the Field (AUTC affiliated project)

Billy Connor (UAF)

In partnership with the Federal Highway Administration (FHA), this project taps into AUTC’s ongoing work with soil stabilization to develop applications that can help a range of transportation projects from roads to runways.

Funded by FHWA, this project utilizes AUTC’s expertise to test a new soil stabilization technique. Building upon AUTC’s ongoing laboratory- focused studies in soil stabilization, researchers performed a practical field test using geofibers and a synthetic fluid to stabilize very loose, sandy, and silty soils. These kinds of soils are common to many parts of Alaska where transportation infrastructure faces excessive maintenance and safety challenges. Researchers wanted to base soil testing and applications at a site in the Matanuska-Susitna Borough near Horseshoe

Lake, Alaska. Researchers then collaborated with FHWA to gather data from this test site as well as other active projects, and identified new test sites in the state of Washington. They aim to devise methods of strengthening soils in these regions to prevent erosion and other infrastructure damage.

Researchers hope to apply this work to a variety of transportation infrastructure needs. Presenting engineers with soil preparation strategies that make use of locally available materials, the project will significantly reduce overall construction costs. This approach can be used for roads, highway embankments, unstable slope management, and remote airports and landing strips. In addition to providing engineers with a variety of applied research results, this project has provided valuable hands-on experience for two UAF undergraduate students—another unique benefit to AUTC’s partnerships with federal and state counterparts.

Attenuation of Herbicides in Subarctic Environments Across Alaska

(AUTC #207110, Seward test site; AUTC #309026, Fairbanks test site)

David L. Barnes (UAF)

These two projects demonstrate how partnership between AUTC and the U.S. Department of Agriculture is helping to create more cost-effective infrastructure protection for Alaska’s railways.

The Alaska Railroad Corporation (ARRC) needs effective, low-cost ways to manage vegetation growth along rail lines. Because manually removing railway brush and vegetation is costly and relatively ineffective, researchers want to know how herbicides might be best used in vegetation removal efforts.

AUTC researchers, together with USDA’s Agricultural Research Service, are investigating the environmental fate, attenuation, and effectiveness of several herbicides currently being evaluated for use along Alaska’s transportation corridors. Questions addressed include: Once these herbicides are applied, how long does it take for them to enter the soil? Where do they go? How long does it take for them to dissipate?

In an affiliated partnership with the Federal Highway Administration, AUTC is leveraging ongoing work with soil stabilization to develop and test applications that can help a range of transportation projects, from roads to runways.

Herbicides have been applied at one field site near Seward, Alaska, at the southern end of the ARRC rail line. Researchers aretracking these applications over two years through a series of soil and groundwater samples to obtain site-specific attenuation data. In Fairbanks, they are performing mass balance studies on the same herbicides using lysimeters installed at the Experimental Farm on the UAF campus. Results will yield a better understanding of the environmental fate of these herbicides in Alaska’s maritime subarctic zone. These tests will provide information on how long the herbicides last, and how effective they may be in treating railway side brush and vegetation in Alaska and other cold regions.

Alaska Hot Mix Asphalt Job Mix Formula Verification (AUTC #309024)

Juanyu “Jenny” Liu (UAF)

Some asphalt pavement does not last as long as it should, which means that every year, the state spends significant sums on repair and maintenance of Alaska’s paved roads. Since hot mix asphalt (HMA) is the major paving material used in Alaska, assuring its quality is critical for contractors and ADOT&PF. Ensuring that contractors out in the field are operating with the appropriate HMA is crucial. This project is assessing HMA quality assurance specifications and evaluating how well contractors meet the requirements of job mix formulas (JMFs).

In recent work, researchers field-tested a HMA as part of a rehabilitation and resurfacing project on the Parks Highway, south of Nenana, and at an Anchorage International Airport (AIA) paving project. HMA mixtures applied under four different scenarios were sampled from nine sub-lots in Nenana and four sub-lots in AIA. The mixtures included specimens mixed and compacted using JMF in the laboratory; loose mixtures collected from windrow, and either compacted in the field using a portable gyratory compactor or compacted in the laboratory; and samples retrieved from the field. Researchers obtained data from ADOT&PF and contractors at each phase of lab/design, production, and new construction. Data included general project information, details of the materials and JMF used in the construction, and all construction test data.

Liu’s team field-tested rehabilitation and resurfacing techniques on the Parks Highway, south of Nenana, and at Anchorage international Airport.

This project is conducting four tests for JMF properties in the university lab, including aggregate gradation, asphalt content, mix volumetrics, and density. Researchers will investigate HMA performance to further verify the JMF and evaluate any impact of the construction process. The project recently completed ignition tests for all its materials and performance tests for materials collected from the AIA paving project.

Project results will help improve current mix design protocols, benefit the asphalt-paving process, and ensure the quality of HMA. Verification will enhance the long-term performance of HMA pavements and significantly reduce the state’s pavement maintenance and repair budget.

Measuring the Effectiveness of Rural Dust Control Strategies (AUTC #107019)

David L. Barnes (UAF)

Extending AUTC’s expertise in road dust reduction, David Barnes of UAF is conducting one of several studies to improve rural dust control.

Dusty, unpaved roads and airports affect the quality of life for many villages in cold regions; roughly 60% of Alaska’s roads are unpaved. Alaska isn’t alone. Of America’s 4.2 million miles of roads, 1.7 million are unpaved. Dust reduces road visibility, causes respiratory ailments, and affects fruit and plant harvesting activities. In addition, loss of fine material reduces road surface quality, increasing maintenance costs as well as wear and tear on vehicles.

Everybody acknowledges the problem, but finding a solution is a contentious matter. Simply paving is often unworkable; costs are high, local materials are often unsuitable, and long-term maintenance may be unavailable. Possibilities for dust control abound, but which will fit best with the subsistence lifestyle practiced in rural areas, and what can the state’s thinly stretched budget afford?

To help address these questions, this project is developing a dust control research map that prioritizes critical areas. It is designing instrumentation and methodology to accurately monitor road dust production. These tools will be used to support ADOT&PF in field-testing various dust control measures in several locations. So far, researchers have qualitatively assessed dust control performance on unpaved runways, tested new instrumentation, and measured palliative performance with this prototype instrument at one rural road site.

Dusty, unpaved roads and airports affect the quality of life for many villages in cold regions; roughly 60% of Alaska’s roads are unpaved. Alaska isn’t alone. Of America’s 4.2 million miles of roads, 1.7 million are unpaved. Dust reduces road visibility, causes respiratory ailments, and affects fruit and plant harvesting activities.

Alaska Specification for Palliative Applications on Unpaved Roads and Runways (AUTC #309015)

David L. Barnes (UAF)

AUTC’s work on dust reduction is not limited to roadway surfaces. For the past seven years, ADOT&PF Northern Region has been applying different dust-control palliatives to rural airport runways. The only guidance in applying these palliatives has come from the manufacturers; typically this material is too vague for much practical use. Engineers are unable to determine whether these products are meeting their own standards or not.

This project, using UAF’s dust-monitoring (DUSTM) instrumentation, is collecting data and comparing the effectiveness of newly laid palliative and older palliative, applied one to three years earlier. From these results, researchers will develop a reasonable performance-based set of specifications that cover the application of dust-control palliatives to unpaved transportation surfaces. These specifications will make it possible for ADOT&PF to choose the best palliative for a community’s needs, and hold vendors accountable for the quality of their products. This project will improve public safety and enhance the effectiveness of this technology.

Eagle Dust Project (AUTC #MISC3)

David L. Barnes (UAF)

As part of a group of projects testing dust control strategies and collecting information across Alaska’s several different environments, ADOT&PF applied a dust-control palliative to the surface of the Taylor Highway near Eagle, Alaska. Over the past two years, AUTC researchers have been monitoring the palliative’s performance and gathering data both at the test site and, as a control, at nearby untreated sites. The final report, which is in preparation, will include detailed testing results and recommendations on palliative application strategies for roadways.

Dust Palliative Performance Measurements on Nine Rural Airports (AUTC #MISC4)

David L. Barnes (UAF)

In the summer of 2009, ADOT&PF began applying dust-control palliatives to nine rural airport runways across Alaska. AUTC researchers are monitoring these runways to assess the quality and durability of several palliatives. Measurements are taken with the UAF dust-monitoring device (DUSTM), a portable instrument that measures lofted dust as it rises from the rear tires of an all-terrain vehicle. Palliative performance will be assessed by comparing the measured fraction of lofted dust produced by the ATV on the treated section of the runway to the fraction produced on the untreated control section.

Researchers have taken measurements within 30 days of the first treatment on each runway and have followed up with another measurement each following year. Recommendations will help ADOT&PF select the most effective out of several products and plan the most efficient application schedule for Alaska’s many unpaved runways.

A Study of Unstable Soil Slopes in Permafrost Areas: Alaska case studies used as a training tool (AUTC #309032R)

Margaret Darrow and Scott Huang (UAF)

The failure mechanisms of unstable soil slopes in permafrost areas are not well understood. Analysis of these slopes requires consideration of soil temperatures and ice content, and their effects on soil strength, which is not part of typical slope stability analysis. These unstable slopes may vary in depth, affecting only the active layer or having a more deep-seated nature. Additionally, the subsurface conditions may be a complex mixture of frozen and unfrozen areas, which affects the groundwater flow and overall slope stability. Whatever their configuration, these unstable slopes possess characteristics that are unique to permafrost regions.

Several unstable soil slopes in frozen ground exist along highways in Alaska’s northern region. These areas of instability require ongoing maintenance and monitoring until possible mitigation strategies are developed.

This study is summarizing three key historic and/or ongoing unstable soil slopes in Alaska. Researchers are conducting on-site visits for each site and reviewing previous design and mitigation strategies to determine possible solutions for stabilizing each slope.

This information and analysis will be summarized in a training program for ADOT&PF engineers that categorizes typical unstable soil slopes in permafrost areas and suggests appropriate mitigation strategies.

Automatic Electrical Deicing System using Emerging Carbon Nanofiber Paper: A Pilot Field Testing (AUTC #410014)

Zhaohui Yang, UAA

Carbon Nanofiber paper is composed in extremely tiny layers, similar to the way ordinary paper is made. This material may help address a growing public safety risk in Alaska and other cold regions. Snow and ice on pavement and bridge decks are a persistent problem, where black ice—a thin, nearly nvisible, and dangerously slick layer of ice—often covers sections of coastal highways and bridge surfaces. A common cause of winter accidents, black ice is difficult for motorists to spot and makes it even tougher for them to stop or slow down. Commuters, travelers, and commercial drivers alike are affected by this problem.

Several types of deicing strategies have been used over the years, but many have unintended consequences for the environment and nearby structures. Salt, for example, is one of the most commonly used deicers because it is cheap and effective. Yet, while sprinkling salt on roadways and bridges is simple, it pollutes the environment and corrodes reinforcing steel bars in concrete, damaging bridges and other structures as well as vehicles. Other chemicals, like calcium chloride, magnesium chloride, and potassium acetate have been used, but these remain fairly expensive for public agencies. Similarly, thermal anti-icing approaches, such as electric self-regulating sidewalks and roads, are both difficult and expensive to install and maintain. Alaska, as well as other cold regions, needs a safe solution to black ice that is both cost-effective and environmentally friendly—and one that will not corrode other structures.

Electrically-activated carbon nanofiber paper may offer a solution. This project developed and tested an innovative deicing technology based on this emerging nanomaterial. It is simple to install, as engineers simply lay carbon nanofiber paper underneath regular pavement. This quick and simple application minimizes interference in pavement and bridge deck construction, and it does not require changes in how the pavement is mixed or applied. If successful, this technology could lower operational costs compared to other deicing methods, as well as lowering maintenance costs by reducing corrosion damage to bridge structures. Moreover, as this method avoids the use of chemical deicers it may also reduce runoff pollution to local water bodies.

A multi-disciplinary team made up of electrical, mechanical, and civil engineers along with five full- and part-time students designed a deicing system that utilizes carbon nanofiber paper. They participated in a test installation on the UAA campus.

Now that the installation project is complete, this test site will be monitored over the longterm to collect information on how the material performs under realistic conditions. Future outcomes will include assessment of the system’s reliability and cost-effectiveness, with an eye toward providing recommendations on using such systems in Alaska.

To learn more about this study, see the project page at: ine.uaf.edu/autc/projects/automatic-electrical-de-icing-system-using-emerging- carbon-nanofiber-paper-a-pilot-field-testing

When shifting rivers threaten important infrastructure, engineers are left with the delicate task of re-directing a river to  save structures that  cost millions, and sometimes billions to build. Together AUTC and ADOT&PF engineers have developed several types of strategies to prevent stream bank erosion.

Completed Surface Application Projects

Investigating Methods for Maturing Concrete in Very Cold Weather (AUTC #107052)

Yongtao Dong (UAF)

Concrete curing is a process used to strengthen concrete, and transportation engineers in Alaska’s arctic climates rely on this to create durable road surfaces—extending the service life of vital transportation infrastructure.

This project developed and tested protocols to determine concrete curing strength during the construction process, so that road crews can build safely and quickly in very cold conditions. But this is a delicate process, and construction teams rely upon tested strategies to make the most durable concrete. To this end, researchers determined the laboratory strength and maturity correlations for concrete mix designs that ADOT&PF teams commonly use. After conducting spring and summer field tests, the project team produced a guide with procedures and computations designed to help ADOT&PF personnel use developed methods on location to better estimate the strength of concrete they pour. The final report is available on the AUTC website (ine.uaf.edu/autc/final-reports/)

Field Study to Compare the Performance of Two Designs to Prevent River Bend Erosion in Arctic Environments (AUTC #309009)

Horacio Toniolo (UAF)

Rivers often change their paths over time, and this can seriously threaten existing infrastructure. In Alaska, roadways and pipelines are vital conduits for people, goods, and resources. When shifting rivers threaten them, engineers are left with the delicate task of re-directing waterflow to save structures that cost millions, and sometimes billions, to build.

This study focused on two erosion-control projects built in Alaska using different design criteria. One was built by Alyeska Pipeline Service Company at Hess Creek to protect the trans-Alaska pipeline. The other was constructed by ADOT&PF to protect the Dalton Highway from the Sagavanirktok River.

Bank erosion along river bends results in lateral erosion, causing streams to shift laterally where they may pose risk to infrastructure. Engineers have developed several types of strategies to prevent stream bank erosion. These include watercourse realignment, a technique of moving water away from the bank that essentially imitates a natural process, to protect the transportation infrastructure from damage. Structures at the two study sites were composed of a series of stabilizing baffles, or barbs, one oriented downstream (Hess) and one oriented upstream (Sagavanirktok).

Lead by UAF’s Horacio Toniolo, researchers gathered hydraulic data, including continuous velocity measurements, at selected points on both waterways. Adding this data to a hydraulic numerical model, researchers simulated different hydraulic scenarios to demonstrate a river’s behavior under different flow conditions at different seasons. These models revealed that the first baffle or barb in a series is the most critical in the whole structure; if the first barb fails, chances that the others will also fail increases significantly. This new information is immediately valuable to current erosion control projects.

Armed with this new model, ADOT&PF personnel are now looking for opportunities to implement the model in different settings, particularly where the agency is planning river training structures. Helping designers plan appropriate structures for actual river conditions, this numerical model will improve the design process for future structures.

Characterization of Asphalt-treated Base Course Material (AUTC #107049)

Juanyu “Jenny” Liu (UAF)

Asphalt-treated bases (ATBs) are often used to increase the durability of new pavements. While ATBs are readily available and low-cost, little data exists on how they perform in cold regions. Hoping to apply their use in Alaska’s arctic climates, this study investigated four ATB types: hot asphalt, emulsion, foamed asphalt, and reclaimed asphalt pavement. These four types have been popular for treating base materials, so the research team collected data on material stiffness, fatigue, and permanent deformation characteristics under different temperatures. The team also compiled the latest research on ATBs to produce a detailed literature review.

Researchers tested ATB materials commonly used for Alaska’s three major regions, and went to ADOT&PF labs to fabricate foamed asphalt-treated base samples. Based on the results, Liu and her team developed comprehensive regression equations for all the studied ATB materials. Using these predicting equations allows pavement designers to make recommendation about resilient behavior of ATBs based on different treatment techniques, ambient temperatures, aggregate properties, and binder contents. The final report is available on the AUTC website (ine.uaf.edu/autc/final-reports/)

Warm Mix Asphalt (AUTC #207086)

Juanyu “Jenny” Liu (UAF)

Cold weather transportation researchers are trying to find more cost-effective and more environmentally-friendly ways to build strong, durable, road surfaces. While there are several warm mix asphalt techniques available, which will perform best over the longterm in cold regions is still under examination. This project evaluated the performance of warm mix asphalts (WMA) using an additive called Sasobit®.

Researchers investigated how materials performed at low temperatures, including their potential for rutting and their sensitivity to moisture. They used both lab and field tests to assess the engineering properties of WMA mixes. Compared with conventional hot mix asphalt (HMA), Sasobit-modified WMAs show lowered mixing and compaction temperatures, and improved workability and rutting resistance but show an insignificant effect on moisture susceptibility. Tests conducted suggest that adding Sasobit to WMA degraded the mix’s resistance to low-temperature cracking. Researchers concluded that additional low-temperature tests and more complete thermal cracking analysis would help clarify the effects of Sasobit on low-temperature cracking.

Helping enhance Alaska’s workforce development, researchers presented these findings across the state in professional seminars and pavement-design classes for both practicing engineers and traditional college students.

Warm Mix Asphalt: Experimental Features in Highway Construction (AUTC #MISC5)

Juanyu “Jenny” Liu (UAF)

One way to enhance the cost-effectiveness of durable surface applications is to find ways to reduce the amount of energy it takes to apply asphalt to a surface. Hot mix asphalt (HMA), used in many conventional paving projects, is typically spread at temperatures between 280° and 320°F. When road crews use warm mix asphalt (WMA), which can be applied at significantly lower temperatures (250° to around 270°F), they can reduce the energy requirements and costs of highway paving. This is why researchers wanted to see if WMA could be applied without adversely impacting pavement performance in Alaska.

One form of WMA involves adding small amounts of water (as steam) to the asphalt mixer system, and ADOT&PF used this approach on a paving project near Tok, Alaska. Liu’s research team collected samples on site and conducted a laboratory testing program to assess how this WMA technique works and to determine if there is any significant difference between how HMA and WMA pavements performed. Tests included material characterization, rutting potential, resistance to fatigue, moisture susceptibility, and performance under low temperatures.

Results show that the engineering properties of the asphalt mixture are not significantly affected by adding steam during production. Liu recommended that tests on field-collected field-compacted specimens for foaming WMA could provide more representative and definitive results.

permafrost & frozen ground

As the nation’s premier facility for cold region transportation research housed at America’s Arctic University, AUTC puts a major emphasis on  its permafrost and frozen ground studies.

While Alaska’s interior and northern regions demonstrate the most dramatic examples of the destructive effects thawing permafrost can have on transportation infrastructure, our location also affords ample opportunities for research. Our unique geography combined with AUTC’s partnership with ADOT&PF positions us as a leader in this field.

AUTC stakeholders—Alaska policy makers, our federal delegation, and engineers who deal with these issues everyday—benefit from AUTC’s innovative research. While diverse, all our projects in permafrost and frozen ground studies aim to help extend the service life of cold weather transportation infrastructure. For state decision makers, this means less expensive, longer lasting bridges, roads, and runways. For the federal delegation, it means maximized maintenance efforts and more cost-effective transportation budgeting—making the most of every dollar Alaska receives for transportation initiatives. AUTC also leads the way for other states wrestling with cold climate transportation issues. For engineers and project planners, our work means new ways of making their work more effective, efficient, and long-lasting.

New Permafrost & Frozen Ground Projects

Impact of Groundwater Flow on Permafrost Degradation and Transportation Infrastructure Stability (AUTC #510011)

Margaret Darrow (UAF)

Climate shifts in Alaska’s extreme environments cause extensive and costly damage to transportation infrastructure. Thawing permafrost, for example, causes significant structural challenges to roadway embankments, increasing life cycle costs and reducing transportation system effectiveness.

Extensive research has been conducted on how changing surface temperatures can affect permafrost and compromise embankment stability. However, we know much less about the impact of groundwater and advective heat transfer upon permafrost degradation below embankments. Studies indicate that groundwater flow along the permafrost table will increase permafrost degradation, accelerating damage considerably faster than atmospheric warming alone. Thus, to maintain long-term infrastructure stability in permafrost regions, we must gain a better understanding of the complex interactions between groundwater, permafrost and overlying embankments.

To this end, UAF researchers Margaret Darrow and Ronald Daanen have partnered with colleagues (lead by Daniel Fortier) at the Université de Montréal (UdeM) to investigate the relationship between groundwater flow, permafrost degradation, and embankment stability. Elements of the collaborative study include field work at a test section on the Alaska Highway near Beaver Creek, Yukon Territory, Canada; laboratory measurements of hydraulic conductivity and unfrozen water content; and modeling of the interaction among these complex phenomena, using coupled mathematical equations in COMSOL Multiphysics (a software package). Researchers will use this data in road embankment simulations that determine how energy advection contributes to the frozen ground through groundwater flow. The results will improve our understanding of groundwater flow through taliks and within warm (near 0°C) permafrost soils with high unfrozen water content. Continued work and data modeling—incorporating both conductive and advective heat transfer processes—will help develop a powerful tool for roadway embankment designers.

Moreover, this work will help designers create robust embankments and more effectively mitigate groundwater flow, potentially resulting in cost savings for transportation infrastructure maintenance, increased life cycle, and improved system effectiveness.

Experimental Study of Various Techniques to Protect Ice-Rich Cut Slopes (AUTC #510010)

Xiong Zhang (UAF)

For more than 50 years, state construction officials have wrestled with the costly problem of uncontrolled erosion, runoff, and slope failures that result from permafrost. The permafrost that underlies most areas of Alaska potentially adds significant development costs in the form of environmental distress, project delays, change orders, and claims that often occur during building.

Researchers Xiong Zhang (AUTC) and Mingchu Zhang (UAF School of Natural Resources and Agricultural Sciences) hope to study potential thermal erosion mitigation techniques in order to find better methods for controlling erosion from cut faces in the first thaw season, effectively reducing many of these dangers and costs.

Cuts in permafrost surfaces are often required to achieve design grades in ice-rich permafrost areas, and excavation and exposure of a cut slope can destroy the existing thermal balance, resulting in degradation of the ice-rich permafrost. While research has been done to address the issue, environmentally acceptable, legal, and economically viable solutions remain rare. Further, new and strict environmental laws continue to increase the trend to make long-accepted ADOT&PF methods for dealing with ice-rich permafrost either undesirable or completely unacceptable.

Zhang and Zhang will study several potential thermal erosion mitigation techniques that address the regulatory concerns raised by current practices. Researchers will construct several test sections in the experimental study and monitor the sections to evaluate the effectiveness of different techniques. The team will offer recommendations and guidelines for design, construction, and for ensuring proper application of successfully tested mitigation approaches on future construction projects that require cuts in ice-rich permafrost.

Supplemental Study to “Using Mirafi Nylon Wicking Fabric to Prevent Frost Boils in the Dalton Highway Beaver Slide Area, Alaska” (AUTC #510020)

Xiong Zhang (UAF) and Michael R. Lilly, Geo-Watersheds Scientific (GWS)

Like the challenges posed by permafrost, frost boils also undermine highway infrastructure in a number of ways. Mirafi Nylon Wicking Fabric is becoming a prevention solution of interest for AUTC researchers, who are testing the new material’s ability to mitigate frost boils and subsequent road damage in the Beaver Slide area, near mile 110.5 of Alaska’s Dalton Highway.

Jointly funded by ADOT&PF, Tencate Geosynthetics, and AUTC, this work began in August 2010 with construction of a test section in the area. While preliminary field results suggest that Mirafi Nylon Wicking Fabric did help prevent frost boils in the area, further research is necessary to provide conclusive data.

Researchers Xiong Zhang (UAF) and Michael R. Lilly (GWS) are extending studies to monitor the test section for another year, in addition to the original one and a half year study. The researchers are concerned that the original monitoring period is not long enough to provide sufficient data to help understand the frost boil problem. The research project will extend the monitoring period to December 2012.

Opposite, starting at the top and clockwise: exposed bank showing vegetation overgrowing the active layer, which overlies a mix of massive ice wedges and frozen soils. Next is an areal photograph showing patterned ground, a term used to describe the distinct geometric shapes formed by ground material in many circumpolar regions. Last, professor Margaret Darrow assembles her data collection system at a remote field site, part of her study on frozen ground movement.

Ongoing Permafrost/Frozen Ground Projects

Stabilization of Erodible and Thawing Permafrost Slopes with Geofibers and Synthetic Fluid (AUTC #410028)

J. Leroy Hulsey and Xiong Zhang (UAF)

Thawing, unstable, and eroding permafrost slopes pose serious challenges for road maintenance crews and transportation engineers. Changes in frozen soils impose safety risks such as sinking and cracks in northern roadways. However, recent research in the use of synthetic fluids and geofibers, which have proven to effectively reinforce subgrade soils in pavements, may mitigate these problems.

Traditional stabilization techniques are costly and require specialized skills and equipment to ensure adequate performance. They also are only marginally effective in the cold climates of Alaska and other northern regions. This project is conducting a large-scale field investigation to study the feasibility of stabilizing erodible and thawing permafrost slopes with geofibers and synthetic fluid. Recent research has shown that geofibers and synthetic fluids can improve very loose, sandy soils—the material often left behind after permafrost thaws. The outcomes of this research will help future engineering teams build safer, more reliable, cost-effective road embankments.

Use of Mirafi Nylon Wicking Fabric to Help Prevent Frost Boils in the Dalton Highway Beaver Slide Area, Alaska (AUTC #RR10.02)

Xiong Zhang (UAF) and Michael Lilly (GW Scientific)

Alaska’s famed Dalton Highway—paralleling the trans-Alaska oil pipeline from the north of Fairbanks to Prudhoe Bay—is perhaps the nation’s most remote road. Yet while few use it for regular travel, an estimated 250 commercial trucks rely on it daily during the winter months; another 160, during summer. As the recent popular television shows Ice Road Truckers and America’s Toughest Jobs have made clear, the extreme weather that abuses this highway causes many challenges for commercial drivers. In particular, the destructive effects of frost boils result in major safety risks and frequent accidents on the Dalton and other Alaska roads.

Frost boils are not a new problem. Summer weather brings snowmelt and thawing permafrost, and groundwater rushes downslope where it often pools near roadways, moves up during winter freezing, and accumulates in the pavement as an ice lens. Frost boils occur during the spring when these ice lenses thaw, disturbing roadbeds and the asphalt that rides on top of them, causing damage. A well-known example of this occurs repeatedly at a road section near mile 110.5 on the Dalton Highway called Beaver Slide, where conventional construction methods have done little to stop the damage.

Wicking fabric technology, like the kind used to make water-wicking athletic wear, may offer a solution to this safety problem. Preliminary lab tests of Mirafi Nylon Wicking Fabric (MNWF) indicate it has great promise as a cost-effective means of solving frost boil problems on road systems. Developed by Tencate Geosynthetics (North America), MNWF features high specific surface area and permeability; these properties may enhance pavement performance by better distributing pooling water and encouraging fast drainage. As opposed to the hundreds of labor hours and mechanical support needed currently to even attempt repairing frost boil damage, including this fabric in road systems may help mitigate, or even eliminate, this destructive phenomenon. This innovation could improve safety, increase a road’s service life, and reduce maintenance costs.

Researchers are evaluating an installation of MNWF at Beaver Slide, using moisture and temperature sensors to gather measurements on both frost boil formation and pavement performance. They are examining soil properties and thermal and moisture changes as well, to improve our understanding of how these soil mechanisms work. Data collected in the past year indicates that this new technique is a great success.

Research results could lead to incorporation of MNWF in the geotechnical engineering curriculum at UAF as well as informing recommendations to engineers for more reliable and economically cost-effective road design.

Geophysical Applications for Arctic/Subarctic Transportation Planning (AUTC #410018)

William E. Schnabel, UAF

Permafrost poses numerous challenges to cold region road and bridge designers. For example, roads and bridges constructed in permafrost areas are often damaged when the thermal state of the soil changes. Road and bridge designs that do not adequately account for these subsurface dynamics can result in flawed structures requiring excessive maintenance or replacement, increasing both safety risks and costs.

This project will help designers make better use of geophysical information when constructing bridges and roads in cold regions. Specifically, researchers will assess the use of geophysical methods such as electrical resistivity tomography (ERT) and ground-penetrating radar (GPR), technology currently under-utilized in arctic subsurface investigations. These methods could be powerful and relatively inexpensive tools for infrastructure planners. Current research indicates that using ERT and GPR together as part of a geophysical survey can effectively map the extent of subsurface ice formations that undermine structural stability, such as ice wedges, ice lenses, massive ice, and taliks (layers of year-round unfrozen ground within a permafrost area).

Scientists at UAF, UAA, and Laval University are finding ways to integrate ERT and GRP into current assessments of subarctic soils. The team will describe four case studies in which geophysical surveys using this technology are implemented into subsurface investigations along road and bridge alignments being conducted by ADOT&PF. Although results will be used to augment existing ADOT&PF projects, the team’s primary goal is to provide guidance on making ERT and GRP a routine component of characterizing arctic and subarctic soils.

In addition, this study will produce initial information for a database describing geophysical properties typical of Alaska’s permafrost and talik conditions. This database will allow engineers to better address the subsurface challenges that drive up maintenance costs and undermine safety. It will also facilitate protocols for carrying out and interpreting arctic/subarctic geophysical surveys, as well as guidance for selecting the appropriate methods and estimating survey costs. So far, the team has conducted surveys at various sites in the Anaktuvuk basin, at the 9-Mile Dalton Highway realignment, and at the UAF Agricultural and Experiment Farm. In future months they will complete fieldwork in the Goldstream Road region north of Fairbanks.

Fast Determination of Soil Behavior in the Capillary Zone Using Simple Laboratory Tests (AUTC #410025)

Robert L. Lytton (TAMU) and Xiong Zhang (UAF)

Freezing and thawing are major threats to infrastructure reliability and safety because they erode strong soils and the roads and structures built upon them. This study seeks to develop a new way to examine soil volume change and soil strength, allowing engineers to address the complex subsurface moisture issues unique to cold regions.

Frost heave and thaw weakening are typical problems for engineers building in northern regions. Thaw weakening makes pavement and other surface structures prone to damage when thawing water weakens the road. Frost heaving occurs when ice forms in the soil during freezing temperatures, then grows, often upward toward the freezing front. These behaviors are caused by water flowing through the capillary zone to a freezing front, where it forms ice lenses.

This project will develop a new way to examine soil strength that is cost- effective, more reliable, and less time-consuming than current methods. Researchers typically use suction-control testing to determine the strength of unsaturated soils. Although suction-controlled tests are the standard for characterizing unsaturated soils, such testing is too laborious, time-consuming, and costly for routine engineering projects. Learning about the stress/strain behavior for only one unsaturated soil can take up to three years, and moisture content measurements are unreliable.

This research team is developing a method for rapidly determining and analyzing unsaturated soil behavior through a new approach, the Modified State Surface Approach (MSSA). The MSSA can potentially reduce the time required to characterize unsaturated soils from several years to a few weeks or days, as well as provide more reliable measurements and representative soil behavior. If successful, this research will produce a useful tool for geotechnical engineers, allowing fast, practical, more comprehensive soil characterization for complicated soil behavior problems. It can drastically reduce research costs, improve reliability, and ultimately create stronger, safer infrastructure.

Using Shallow Anchors and an Anchored Mesh System for Cut Slope Protection in Ice-Rich Soils (AUTC #207121)

Xiong Zhang (UAF)

Permafrost soils present special problems to builders of roads and other transportation infrastructure in Alaska. When a sloped bank in a permafrost area is cut to make way for a road, the soil may thaw and slump or collapse, causing damage to infrastructure. In addition, as many as six years may pass before new vegetation restabilizes a cut bank. While engineers can design embankments to compensate for these soil changes and protect roadways, there is growing concern that the eroding soils may impact water quality and fish habitat. Engineers are looking for new designs that better protect the immediate environment, meet federal guidelines, and remain economically viable.

Builders have tried many strategies for slope stabilization, some more effective (and more expensive) than others. One strategy is to use wire netting held in place by soil anchors, but little information exists on how this approach works in Alaska’s frozen, shallow, silty soils. This project, in partnership with ADOT&PF, is investigating how shallow anchors perform in frozen soils. Project outcomes include designing an anchored wire mesh system to protect and stabilize ice-rich cut slopes. Anchor creep tests have been completed in the laboratory, and ongoing anchor field tests and numerical simulation analyses continue. The findings will be useful for other types of mitigation strategies, including highway retaining walls, and for addressing rockslide areas.

These improved strategies will help control maintenance costs and water resource concerns often related to thawing permafrost.

Evaluating In-Place Inclinometer Strings in Cold Regions (AUTC #309022)

Margaret Darrow (UAF)

In cold regions, subsurface movement of frozen ground impacts transportation infrastructure, threatening roads, bridges, runways, railways, and other vital structures. Because knowledge about the subsurface is so important for transportation planners, researchers are striving to better understand how these forces work.

This study is an effort to improve how inclinometers—tools used to measure ground movement—perform in cold regions. Inclinometers measure vertical and horizontal ground movement on slopes, embankments, bridges, retaining walls, and other structures.

Current inclinometer technology presents some drawbacks. Since data acquisition requires manual measurements, for example, workers face expensive and potentially dangerous travel. Weeks or months often pass between manual readings due to budget considerations, causing workers to merely interpolate the recorded data. Accurate data collection varies, depending on the care and skill level of the person taking measurements. The inclinometer casing has limited flexibility and can shear when excessive ground movement occurs. In addition, the inclinometer probe length limits the amount of deformation a casing can experience before readings are no longer possible.

A new type of geotechnical instrumentation incorporates Micro-Electro-Mechanical Systems (MEMS) accelerometers, which were first used for automotive air bags. Automated in-place MEMS (AIMIS) technology allows them to be directly inserted in the ground, avoiding the setbacks of manual methods. These accelerometers are more flexible and can withstand greater ground movement. When the installation is accompanied by a remote power supply and a telemetry link, they can provide nearly continuous observation of ground movement without frequent field trips. Moreover they are potentially reusable; they can be removed from one installation and placed into another, resulting in further cost savings.

Since the AIMIS technology is new, its use has not been fully evaluated, especially in cold regions. Although AIMIS are designed to be reused, techniques for extracting installed strings are in their infancy and are problematic. New extraction techniques for use in frozen ground may need to be created and evaluated, and as with any equipment used in cold regions, the durability of AIMIS at subfreezing temperatures needs to be evaluated.

Researchers will compare AIMIS against the existing methodology, evaluate its cold region versatility and accuracy, and test its ease of use and recoverability. The project will also evaluate AIMIS for applications in Interior Alaska that include monitoring creep in frozen ground and identifying and monitoring a slide shear zone. Researchers will also compare two different AIMIS products with the existing manual method and with each other to identify any benefits of one product over another. Fieldwork and data analysis will allow researchers to develop a set of Best Practice Guidelines for using AIMIS applications.

A new type of geotechnical instrumentation incorporates Micro- Electro-Mechanical Systems (MEMS) accelerometers, which were first used for automotive air bags.

Completed Permafrost/Frozen Ground Projects

Seasonally Frozen Ground Effects on the Seismic Response of Highway Bridges (AUTC #107014)

J. Leroy Hulsey (UAF)

How does frozen ground affect bridge performance? Seasonally frozen ground is stiffer than unfrozen ground. Although we think of bridges as solid and unbending, every bridge will—and should—flex a little, under the right conditions, for example during an earthquake. Bridges built on deep pier foundations seem to become less flexible in winter. This project studied the influence of seasonal change on pier structures, measuring how structures responded to seasonal changes, and how bridge stiffness changed over time.

A joint effort between civil engineers at UAF, UAA, and Iowa State University, this project monitored a variety of bridges, including some with piers sunk in ice-rich soils. The team also analyzed models of bridge structures under seismic loading and monitored temperatures at test sites to determine the depth and seismic resistance of these structures.

Project results will contribute to new, guidelines to help ADOT&PF design for better bridge performance. This project’s results have contributed to ADOT&PF efforts to plan for cost-effective monitoring and repair of Alaska’s bridges.

Preservation of the Alaska Highway, Phase 2 (AUTC #309035)

Daniel Fortier (Laval University) and Yuri Shur (UAF)

Combining AUTC’s permafrost expertise with applied fieldwork and the latest in 3D modeling technology, researchers on this collaborative project looked at ways to mitigate permafrost damage to the Alaska Highway, with the aim of curbing maintenance costs and reducing safety risks by extending the highway’s service life.

The research team collected data along sections of the highway, using instrumentation installed as part of an earlier project. This included fine- scale thermal monitoring of permafrost mitigation techniques, surface drainage monitoring and snow dynamics monitoring. They lab-tested soil samples as well as performing extensive data analysis and modeling. Project fieldwork included constructing a snow shed along one section of the highway embankment. Similar to a tunnel, a snow shed is a wooden structure that provides a roof over a road embankment to block out precipitation, sunlight, and other hazardous weather. By keeping the insulating snow off the ground surface, the soil is exposed to cold air flowing over and under it. A snow shed helps cool the soil surface by deflecting heat from the ground and the air immediately above it, encouraging permafrost to stay frozen.

Researchers established a permafrost database and 3D cryostratigraphic model linked to a geographical information system (GIS). Along with thermal data, the database and cryostratigraphic model allows researchers to evaluate how well their techniques mitigate surface damage. Project results will help engineers in Alaska and western Canada prevent damage to the Alaska Highway and other infrastructure that crosses ice-rich soils. By working with the Yukon Highway Public Works Department on new design implementations, the project is already helping mitigate damage from thawing permafrost. This work will increase the Alaska highway’s service life, prevent costly maintenance, and improve public safety.

Evaluating Liquefaction Resistance in Degrading Permafrost and Seasonally Frozen Ground (AUTC 107041)

Kenan Hazirbaba (UAF)

Permafrost degradation in regions of high seismic activity increases the potential for soil liquefaction, which threatens transportation and utility infrastructure. This became all too evident during the November 2002 Denali Earthquake (magnitude Mw 7.9).

Concerned by this seismic threat, researchers wanted to know more about how freeze-thaw cycles impact soil liquefaction and, by association, structural stability. This project conducted lab studies to investigate the liquefaction resistance of frozen and seasonally frozen ground. Researchers examined how soil liquefaction is influenced by freeze-thaw cycles throughout the year and how it is impacted by temperature distribution in degrading permafrost. The research showed that soils may undergo liquefaction at below freezing temperatures.

Results helped establish criteria for liquefaction susceptibility in thawing permafrost and soils that regularly undergo freeze-thaw cycles. This information will help engineers better design and test structures in arctic, seismic-prone environments.

Geological Investigations for the Dalton Highway Innovation Project as  a Case Study of Ice-rich Syngenetic Permafrost (AUTC #207122)

Yuri Shur and Mikhail Kanevskiy (UAF)

What scientists call “syngenetic” permafrost actually grows upwards in size as sediments are deposited on the surface, causing major maintenance and safety problems for road designers hoping to cross such areas.

ADOT&PF plans to construct a new section of the James W. Dalton Highway in northern Alaska—a three-mile-long section that avoids a steep climb, making it safer to drive than the existing road. But this new section of highway will cross an area of extremely complex frozen ground, characterized by ice-rich, syngenetic permafrost that can be up to 100 feet thick and contain huge ice wedges.

Designing a road to cross such an area depends on having the best geotechnical information available, on continuous monitoring, and timely maintenance. AUTC permafrost experts Yuri Shur and Mikhail Kanevskiy helped prepare for this construction project by performing a geotechnical investigation of the area, training ADOT&PF engineers in permafrost behavior, and developing a methodology for describing, sampling, and testing the area’s syngenetic permafrost. In addition to supporting the best design possible for the highway, project results will help future construction projects throughout the circumpolar North and contribute to the education of a new generation of engineers at the University of Alaska.

Impact of Fines Content on Resilient Modulus Reduction of Base Courses During Thawing (AUTC #107045)

Juanyu “Jenny” Liu (UAF)

This project investigated base materials (D-1 base course materials) commonly used in Alaska’s roads. Liu’s team systematically evaluated changes in the stiffness (resilient modulus, or MR) of these materials, as well as how their soil-water characteristics changed under freeze-thaw cycles. She wanted to know how different percentages of fines and moisture influenced material properties used in road pavement. Field tests in three regions and subsequent lab research led to insights that will produce better pavement designs, especially in rural areas where project engineers often rely on locally available materials with high fines content.

Liu found that the MR of D-1 base course material is highly dependent on temperature. MR was significantly lower after only one freeze-thaw cycle, and specimens with low initial moisture contents demonstrated even lower MR. Generally, after a freeze thaw cycle, base course with the highest fines content contributed to the lowest MR. MR decreased as moisture content increased under different confining pressure and fines content levels.

Liu’s team developed regression equations to correlate MR values with physical properties (moisture and fines contents), stress states, and temperature conditions for D-1 base course materials. For D-1 materials tested in this study, at room temperature, MR was found to be a function of stress state, moisture and fines contents. At subfreezing temperatures, MR was a function of deviator stress, temperature, and aggregate type.

These equations can be used to predict MR values of Alaskan D-1 materials for pavement design. These results will help efforts to extend road service life and reduce maintenance and safety risks.

Effects of Permafrost and Seasonally Frozen Ground on the Seismic Responses of Transportation Infrastructure Sites (AUTC #107017)

Zhaohui Yang, UAA

If you build a bridge in a permafrost area, is it more or is it less likely to survive an earthquake? Transportation engineers are eager to learn about how permafrost changes infrastructure’s ability to withstand seismic force, like that generated during an earthquake.

This interdisciplinary project combined seismic data recorded at bridge sites with computer models to identify how highway bridges built on frozen ground behave during an earthquake. Two sites—one in Anchorage and another in Fairbanks—were selected for seismic testing. In assessing seismic motion in frozen soil, researchers considered the thickness of seasonally frozen soil, depth and thickness of permafrost, and depth of the bedrock. Results showed that the presence of frozen soil, particularly permafrost, significantly changes ground motion characteristics.

Study results will contribute to new guidelines that help engineers design better highway bridges and embankments in Alaska, ideally identifying how to account for permafrost effects in a simpler manner. These guidelines will help designers create more durable, long-lasting roads and reduce maintenance and safety risks.

Preservation of the Alaska Highway, Phase 1 (AUTC #107054)

Daniel Fortier (UAF)

Increasing the life span of the Alaska Highway depends upon understanding and mitigating the destructive effects of permafrost. The Alaska Highway, the only road connecting Alaska to the contiguous U.S., crosses large areas of permafrost-rich soils, which may thaw, shift, erode, or re-freeze seasonally—sometimes daily.

Highway reconstruction in the mid-1990’s damaged the organic layer that insulated and protected the surrounding permafrost. Since then, heat has transferred through the road, melting the ground ice underneath. The thawing and settling ground has created dips, bumps, potholes, and cracks in the road. Throughout the past 10 years, the climate has been relatively stable, but if temperatures become warmer, permafrost degradation and the rate at which the road is damaged will increase. Working with the Yukon

Highways and Public Works (YHPW), AUTC researchers explored ways to slow this permafrost degradation. They selected test sites, characterized surrounding soil conditions, and installed instruments for long-term data collection. Team members, working with engineers at YHPW and Laval University, finalized designs for mitigating permafrost degradation and highway embankment subsidence. This research helped transportation engineers better understand the subsurface dynamics that impact road quality, and the associated maintenance and safety concerns. To learn more about this project, visit ine.uaf.edu/autc/.

Measuring Temperature and Soil Properties for Finite Element Model Verification (AUTC #RR08.11)

Margaret Darrow (UAF)

This study sought to develop ways of stabilizing embankments to reduce permafrost thawing, which severely damages roads and other structures. To do this, the project refined current analytical tools used to assess permafrost conditions. ADOT&PF personnel frequently use a program called TEMP/W to conduct thermal modeling of various embankments to reduce the thawing of ice-rich permafrost through thermally stable embankment designs. The study’s goal was to verify the thermal modeling results produced by TEMP/W. Temperatures and soil properties were measured at two different sites underlain by permafrost in Interior and Southcentral Alaska. While historic air temperature data provided an approximation of the regional climate, the data produced model results that were too cold by several degrees. Using air temperatures measured at each site resulted in models that closely matched the measured soil temperatures, and either matched or overestimated active layer depths. Using the overestimated active layer depth for design purposes would result in a more conservative embankment construction, which is a favorable approach if a warming climate is considered. This realization helped refine the current use of TEMP/W, giving engineers a clearer picture of the thermal interaction between permafrost and overlying embankments.

Nylon Wicking Fabrics (AUTC #RR10.02)

Xiong Zhang (UAF)

Innovative materials are helping preserve road surfaces and prevent erosion on Alaska’s highway system. Mirafi Nylon Wicking Fabrics (MNWF), for example, can be used underneath road surfaces to move water away from areas where it pools up and freezes—causing roadway damage and safety risks. Often, developing these materials requires a combination of field and laboratory testing.

This project applied lab testing to a privately developed geotextile—a fabric used to reinforce or drain soil—as part of a road repair project on Alaska’s Dalton Highway. To assist highway designers, researchers wanted to see whether MNWF would capture water welling up through foundation soils and route it to the side of a road, leaving the soil above drier and stronger. A collaboration between Tencate, which provided the geotextile, ADOT&PF, which installed the new material, and AUTC, which provided data collection monitoring, this project collected data over a two-year period to reveal how well the material performed.

Results are helping northern region road surface engineers design more resilient roads that require less maintenance.

Researchers worked with private industry to develop and install a new nylon wicking fabric under pavement to reduce or eliminate “soft spots”—areas where water pools underneath the pavement, causing rapid degradation and potholes.

Cover: Top left and clockwise: AUTC researcher Daniel Fortier collects information as part of the Alaska Highway Preservation project. Photo by UAF student Eva Stephani. Photo of ferry docked at an Alaska port by Andrew Metzger. Photo of “Full-Scale Testing of Steel Bridge Pier” courtesy of Steven Fulmer, North Carolina State University. Photo of asphalt application by ADOT&PF staff courtesy of AUTC researcher and UAF faculty member Juanyu Liu.

Page 2: Photo of Billy Connor, AUTC Director, by S. Boatwright, INE/ AUTC staff.

Page 4: Photo of A. Armstrong courtesy of Armstrong. Photo of Kessler courtesy of Kessler. Photo of Bob Pawlowski courtesy of Pawlowski. All other board member photos by Institute of Northern Engineering staff.

Page 5: Photo of Zhaohui Yang courtesy of University of Alaska Anchorage. Photo of Sonia Nagorski courtesy of E. Hood. Photo of Rob Harper by Jill Dewey-Davidson. All other photos by K. Hansen, INE.

Page 6: Photo of Billy Connor and Clint Adler by K. Hansen

Page 8: Photos of Rodney Collins by Todd Paris, UAF Marketing & Communications.

Page 9: All photos by K. Hansen.

Page 10: Outreach design photos, top and clockwise: Eva Stephanie, AUTC funded student, in the field; photo by Mikhail Kanevskiy, INE. Student Li Peng presents his research at an AUTC Governing Board meeting; photo by Rob Harper, AUTC. Student Danielle Duncan prepares herring eggs for toxicity testing, part of a project lead by UAF faculty member Bob Perkins; photo by B. Perkins.

Page 11: Photo of Kanevskiy, Collier, and Shur by Hugh French, Professor Emeritus, University of Ottawa. Photo of truck on Dalton Highway by Dennis Witmer, UAF. Photo of salmon drying on rack by Guido Grosse, UAF.

Page 12: Photo of David Barnes presenting his research to the AUTC Governing Board by R. Harper.

Page 14: AUTC by the Numbers illustrations by K. Petersen and Boatwright.

Page 16: Transportation Asset Management design photo by K. Hansen.

Page 17: (lower right) Photo of Jeffrey Miller by Jeffrey Miller.

Page 27: Photo of field testing for RFID Technology in Construction project by Oliver Hedgepeth, University of Alaska Anchorage.

Page 28: Photo of ADOT&PF staff clearing the results of a bank collapse from the highway by Margaret Darrow, College of

Engineering and Mines at UAF.

Page 29: Illustration of roundabout system near Anchorage by graduate student Xuanwu Chen.

Page 30: Structural integrity design, from left and clockwise: Two photos show PhD student Huajie Wen performing tests on samples in a lab at Washington State University; photos by Dr. Fangliang Chen, WSU. Photo of Dr. Andrew Metzger, in the field as part of the “Response of Pile-Guided Floats Subjected to Dynamic Loading” project, by graduate student Jason Kwiatkowski.

Page 31: (lower right) Photos of “Full-Scale Testing of Steel Bridge Pier” courtesy of Steven Fulmer, North Carolina State University.

Page 40: Surface application design, photo by graduate student Peng Li. Page 41: Photo of Natalia Kulchitskaya by P. Li.

Page 52: Permafrost and frozen ground design, from top and clockwise: Exposed bank showing ice wedges and areal photo of patterned ground by M. Kanevskiy. Photo of Margaret Darrow installing remote data collection system by student Travis Haller.