Cold Regions Engineering 2009: Cold Regions Impacts on Research, Design, and Construction

A projected railway bridge across the Shchuch'ya (Pike) River is located in the south of the Yamal Peninsula (67°29'N, 67°26'E) in the zone of continuous permafrost about 120–150 m thick in river valleys. Permafrost temperature averages out at –0.2 to –0.3°C on the right bank formed of high flood plane alluvial deposits. On the left bank formed of Late Pleistocene lake-shore-alluvial deposits, the ground temperature is –3.0°C at the distance of 78 meters from the river. Ground temperature on the left bank has increased on the average by 0.8°C for the last 20 years while the air temperature increased by 1.2°C for the last 50 years in the study area. The ground temperature on the right bank hasn't changed for the last 20 years apparently because of heat-insulating effect of the land fill which is by 2 to 2.5 m thicker on the right bank than on the left one.

Shishmaref, Alaska is located on Sarichef Island in the Chukchi Sea. Sarichef Island is composed of very fine-grained sand permafrost, most likely wind-blown deposits formed as dunes when global sea levels were much lower. With present day sea levels and changing climatic conditions in the region, these permafrost soils are more susceptible to erosion from wind, wave and ice forces. In recent years, erosion along the seaward shoreline has caused the loss of several homes along the shoreline. To collect more information about the permafrost conditions on the island, the Corps of Engineers Alaska District, in conjunction with the Cold Regions Research and Engineering Laboratory (CRREL) conducted ground penetrating radar and resistivity studies in 2008. This data will be used to estimate the depth to and thickness of the permafrost.

The tunnel in the Plateau Permafrost Region has many difficulties to construct, for there are chilly climate and plateau condition, frozen soils, absence of oxygen, frost heaving in frozen soils. How to overcome these difficulties is the key technology for tunnelling in the permafrost region. This paper discussed the key construction techniques of the Fenghuoshan tunnel, which have been successfully constructed. It includes a heat insulation layer between the lining and initial supporting of the tunnel, an intact waterproof and drainage system, and special construction technique for concrete at low temperature to alleviate the frost damage.

Gold miners in the north were the first to develop the techniques for thawing permafrost. They first used fires and hot stones to thaw frozen ground, until steam thawing was discovered in 1898 by Clarence J. Berry. Then miners soon started experimenting with hot-water in place of the steam, however hot-water thawing was never widely used. Then in the late-1910's, cold-water thawing was introduced in two methods called the Miles Method and the Pearce Method. Both cold-water methods were much more economical and efficient compared to steam thawing. These Canadian and Alaskan thawing methods soon spread to Russia where they adapted and further developed it. The methods were also adapted for civil engineering work in northern regions. Today, these thawing methods are still used in construction and mining.

Erection of covered stadium "Zapolyarnik" in Norilsk with a special internal microclimate on permafrost demands application of special actions for preservation of the permafrost condition of the soils. The task for choice an effective way of maintenance of stability of a field of stadium which will be used as a football field during the warm period of year as football and as an ice arena during the cold time is put and solved. The problem of maintenance of stability of the basis of a field and the stadium bases has the purpose — non-admission of the seasonal or long-term soils bases thawing through, including existing improperly sorted out soils of the powerful technogenic cushion fill. The exception of negative development unpredictable settlements - the bases soils blows up, capable to cause deformation the construction, is reached due to the transfer of the existing soils of the in bases into the stable permafrost state, including those which are close to the surface. Stable frozen condition of the soils of the bases of the football-ice field of the stadium is provided by the restriction of an unstable zone of the seasonal frost penetration - soils thawing through within the geotechnical system arranged on the existing surface and possessing with non-subsidence and non-blowup properties at the temperature changes, including a transition through 0°C. Quantitative forecasts are carried out by means of solving of a series of a task of non-stationary heat conductivity taking into account the mobile border of the phases separation (so-called Stephan condition). As a result of researches the temperature fields, peculiar for the soils of the bases during this or that period of time (the forecast is for about) are received at those or other types of influences through a surface. Simulation for seven various types of the arrangement of the artificial basis for the football-ice field is executed. The optimum multilayered construction arranged after maximum natural soils frost penetration of the basis is chosen. Temperature modes of a microclimate of a construction in winter and summer time of year are defined. The technical decision on the arrangement of the pile bases-covers for bearing arches of a covering of stadium is developed.

Eagle River Flats is an estuarine salt marsh located on Fort Richardson, AK. It has been the main impact area for artillery training for over 60 years. In 1990, large reported waterfowl die-offs (>1,000 ducks/year) were attributed to white phosphorus residues in ponded and marsh areas from the detonation of military smoke munitions. A remediation strategy of temporary draining of contaminated ponded areas followed by capping of isolated locations was specified in the Record of Decision (RoD) by site regulators in 1998. Remediation by pumping of the ponded areas was carried out from 1997 until 2007, when the initial remedial action objectives were met. Many small, isolated locations remained contaminated, however, resulting in continued low rates of waterfowl mortalities. Capping these sites was thus required by the RoD to prevent waterfowl access to the contaminant. Our strategy was to conduct capping operations over the frozen salt marsh to reduce costs, minimize environmental impact, and improve safety while working in an active impact area. By mid-February, there is sufficient ice, continuous cold temperatures, and daylight to conduct operations. The process requires an unexploded ordnance technician to sweep the access routes and sites prior to plowing to expose the ice surface. Two days are allowed to freeze up and strengthen the roads. Geotextile is then laid at the pre-marked capping locations and a layer stone is piled over the Geotextile as capping material. When the ice melts in the spring, the stone is kept consolidated by the geotextile, settling over the contaminated area and isolating it from waterfowl. A test capping operation in 2007 was successful. A full-scale capping operation was carried out in February of 2008. The number of ducks killed by white phosphorus poisoning fell from 35 in 2007 to eight in 2008. The corresponding median mortality rate for the overall duck population fell from 0.9% to 0.3. Ground surveys of the treatment area indicated no adverse environmental impact. Further work was conducted in March of 2009 to address the remaining contaminated areas and to conduct minor maintenance. All capped areas have been sampled along their periphery to ensure completeness of coverage.

First seen on Lake Winnibigoshish in a U.S. Forest Service demonstration site, a constructed rock beach is laid in front of a steep, high, eroding bank to encourage the bank to heal itself and vegetate. A berm of larger rock is placed on the three sides which are in the water. Then smaller rock or gravel is placed inside the berm. The larger rock holds the shape and resists wave action while the smaller rock dissipates the energy and provides space for the retreat of the water away from the steep bank. The Natural Resources Conservation Service (NRCS) used this technique on Sugar Point on Leech Lake to protect an eroding lakeshore. This design was also specified to control erosion on Little Pelican Island in Leech Lake and to enlarge the habitat of the threatened common tern (Sterna hirundo). In both cases, the rock was hauled into place during the winter and placed on the ice. As the ice thawed, the materials fell into place. These projects were installed between 1999 and 2001 so have now withstood several years of varying climatic conditions and wave action.

The Corps of Engineers is embarking on the next phase, Phase III, of Cold Weather Admixture Systems (CWAS). CWAS is an innovative approach to conventional cold weather concreting. Since its inception several years ago, the Corps continues to develop this technology to benefit the user and change the approach to winter concreting. Chemical admixtures are routinely used to accelerate cement hydration and promote early strength gain in fresh concrete. To date, no single admixture, when used within the manufacturer's recommended dosage, is capable of preventing fresh concrete from freezing. External heating is still required to maintain a curing environment. This necessitates additional resources (time and money) and is expensive, given volatile energy prices. To fill this void, CWAS uses an ‘off-the-shelf' approach of suites of admixtures that, when used in combination, protect fresh concrete to an internal concrete temperature of –5°C. The cement hydrates and the concrete gains strength even when the temperature is below freezing. Phase I showed the feasibility of the CWAS approach and uncovered potential long-term durability benefits. Phase II further investigated CWAS formulations using elevated dosages of chemical admixtures. Throughout this time period, numerous field demonstrations have been conducted to introduce the CWAS approach to State Departments of Transportation and the U.S. Army. CWAS is catching on. The next phase seeks to optimize the admixture combinations tailoring the mixes to site-specific conditions based on the geometry and forecasted weather conditions. This capability makes CWAS a powerful tool providing users greater flexibility for winter concrete construction projects.

Essentially all areas of Canada are affected by significant seasonal frost penetration. The effect of the frost penetration on roads and highways, especially the amount of total frost heave and the effect of the subsequent thaw, varies with soil type. Road design and construction must consider the effects of frost heave and subsequent spring thaw. The location and amounts of differential frost heave are especially important to pavement performance. Frost heave behaviour can be manifest at pipeline crossings as "reverse frost heave", where the ground above the pipeline does not heave as much as the adjacent ground. If the amount of differential heave within pipeline crossing is large, it can lead to rough, and potentially unsafe, driving conditions. In the case of pipeline crossings, if rough road surface conditions occur in the right of way, highway agencies typically request compensation for additional maintenance costs from the pipeline company. A case study that shows the effects of differential frost heave at a pipeline road crossing is presented.

Ground freezes from the surface downward, and during this process soil moisture is drawn upward. The moisture content of soil that has frozen is high, whereas the moisture content of non-frozen soil below that is low, because water is drawn upward toward the soil that has frozen. If high-moisture soil can be improved to yield low-moisture soil using this phenomenon, low-cost improvement will be possible. Soil moisture change through winter were monitored in outdoor experiments. The results confirmed the feasibility of improving unsuitable soil with high water content through freezing. It was also found that improvement at 15 to 20 cm below the frozen surface was effective, and that the water content of soil poured into an outdoor earth tank decreased from 300 to 150% over a period of two years involving two freezing periods.

In this paper, we report the differences between frost susceptibility of rock and soil. Our research consists of two types of frost heave tests. One test uses solid rock samples. The other uses artificially-shattered, grainy rock samples. Rock can be treated as soil by artificially shattering. We conducted these two types of frost heave tests on 5 types of rock to investigate the differences between frost susceptibility of solid rock and grainy rock. From the test results, non-frost-susceptible rock did not change its frost characteristics in solid and grainy condition. On the other hand, the frost characteristics of frost-susceptible rock changed dramatically in solid and grainy condition. To determine the factors behind these test results, we compared the physical characteristics of solid rock sample and grainy rock sample. These comparisons clarified the structural difference between solid rock and grainy rock affects the frost susceptibility. These facts above indicate that the frost susceptibility of rock and that of soil are different.

Recent economic trends have sparked renewed interest in the development of a gas pipeline to transport natural gas from Alaska's North Slope to markets in the contiguous United States. A buried chilled gas pipeline is a suitable design choice because of safety and environmental concerns. One major drawback is the interaction of the frost bulb with unfrozen, frost-susceptible soils. From 1999 to 2003, the University of Alaska Fairbanks and Hokkaido University in Japan ran a joint experiment to study the behavior of a full-scale, buried chilled gas pipeline. The pipeline, located outside of Fairbanks, Alaska, was constructed across a permafrost/non-permafrost boundary, in order to study the upheaval and stresses induced in the pipe due to differential frost heave. This paper details a small component of this project, namely the interaction between the frost bulb and the active layer immediately above the pipe. The temperature interaction at this interface was modeled using TEMP/W, a two-dimensional finite element program. Analysis of the model results indicates that the modeled temperatures correspond well to measured temperatures. The model results also indicate that at several times during the summer months, the frost bulb above the pipe was dramatically thinned due to spikes in the pipeline gas temperature. Coupled with cumulative stresses created in the pipe due to differential heave, this may result in loss of pipe structural integrity and ultimate failure. These results suggest that burial depth and the type of foundation soil present are critical elements of the final pipeline design.

The impacts and detrimental effects of frost in regions that experience seasonal variation are well documented. The effects of successive freezing and thawing cycles on soil and other substrates, as well as vehicle mobility through the surface-vehicle interface, play a prominent role in transportation. Freezing and thawing are not limited to only geographic locations that experience severe and prolonged cold; even brief periods of low temperatures or freeze-thaw cycling can disrupt transportation operations. At selected locations in North Korea, the depth of frost penetration was estimated using a one-dimensional heat flow model based on the Modified Berggren solution. At one of the locations, the progression and duration of frost penetration over five successive freezing seasons was estimated using a separate one-dimensional heat and moisture flux model. With uncertainties regarding climate change under consideration in design and operations, this type of analysis is even more crucial. A spreadsheet and graphical user interface (GUI) are proposed for ease-of-use by persons unfamiliar with thermal analysis and heat transfer in soils. A tool of this type would lead users through the necessary calculations and assumptions.

Post-Tensioned slabs-on-grade were used for the foundations of a condominiums development in the mountains of Colorado near Silverthorne. The site is located near the Blue River and has a high water table and silty soils. Because an unheated patio was cast as an integral part of the post-tensioned slab, the edges of the slab experienced intolerable heave due to frost penetration under the patio. The migration of the freezing front and the resulting frost heave were modeled using commercial software. The design defects that led to the frost penetration were identified using the results of the analyses. The results also provided input into the design of remediation plans.

It is known that chilled gas pipelines buried at a boundary between permafrost and non-permafrost are subject to severe bending deformation since they are held tightly in the permafrost whereas the growth of frost bulbs in the non-permafrost region causes frost heave of the pipes. However, the flexural rigidity and the behavior of the pipeline and the surrounding frost bulb as a composite structure have not yet been studied, although they are important factors in evaluating structural safety and stability. The purpose of this study is to experimentally determine the interactions between a chilled gas pipeline and a frost bulb under the simplified condition of axial symmetry, and also to evaluate the adfreeze strength of the frost bulb and its dependence on boundary stress and temperature.

There widely exists permafrost over Qinghai-Tibetan Plateau. Many roads have to pass permafrost regions. In northeast edge of the plateau, a section of a road has been suffering from frost heave damage for many years. In 2004, a drilling investigation was carried out. It was found that the section of the road was built on a permafrost island, and the soil in active layer belongs to the frost-susceptible silt. Springs on mountain slopes supply the silt with sufficient water. Samples of the silt were taken back to conduct frost heave tests. The frost heave tests were conducted under three moisture conditions, namely sufficient water supply, at liquid limit water content without water supply, and at plastic limit water content without water supply. Test results show that a considerable frost heave appears for the water supply samples, and multi-layer segregated ice is observed. On the other hand, the frost heave is not obvious while keeping water content of samples below its plastic limit. Based on the results, reasonable suggestions were proposed to the road re-construction.

One of the primary tools used in decentralized urban stormwater management is routing runoff to bioretention systems integrated into the landscape (Oberts, 2003). To date, observation suggests that bioretention systems continue to infiltrate during the winter to varying degrees; however, little field research is currently available to quantify their snowmelt infiltration performance. A three-year study funded by the Water Environment Research Foundation (WERF) field-tested the cold climate hydrologic performance of four existing bioretention cells in the greater Twin Cities, MN, region. Sites were selected based on varying design applications including parking lot runoff, street runoff in a residential setting and a commercial application, in soils from sand and sandy loam to clay loam. The primary hydrologic test consisted of applying up to 6,000 gallons of water to a bioretention cell under various frost conditions. The synthetic snowmelt infiltration rates at the surface were measured as the pool receded while dynamic soil moisture readings tracked the subsurface water movement through the soil profile. Data on air, water and soil temperature, snow depth and frost penetration were collected on site. Measured responses reveal that these bioretention cells maintained hydrologie function in cold climates including many cases where rapid infiltration occurred. The primary study findings are that bioretention systems designed successfully for warm climate conditions will likely perform well in cold climate conditions and a well draining soil-type is the single most important design characteristic. The type of frost, rather than the presence or absence of frost, strongly influences bioretention performance, restricting infiltration under concrete frost conditions and facilitating rapid infiltration under granular frost conditions. Under-drains affect both the range of infiltration rates and the overall function.

The purpose of this study is to deduce a formula for the relationship between the unfrozen water content and temperature (RUWCT) of frozen soils. This deduction is based on analyzing the free energy in the frozen soil. The deduced formula, with three experimentally determined parameters, is similar to the widely-used formula, which only has two parameters. To verify the practicality of the deduced formula, this study uses documented experimental data to regressively calculate the parameters of the deduced and widely-used formulas, and to evaluate the freezing points of frozen soils. The results show that, the deduced formula can predict the RUWCT of frozen soil very well, while the widely-used formula could only predict the RUWCT of the frozen soil with lower water content. The results also indicate that the freezing point calculated from the deduced formula is closer to the experimental data. Based on the results, it is recommended that when the temperature range is not greater than 20°C and the water content of frozen soil is less than 40%, the widely-used formula should be used to predict the RUWCT of this frozen soil. Otherwise, the deduced formula is recommended to predict the unfrozen water content of frozen soil.

The aim of this study is to estimate the permafrost degradation in the Muli coalfield, an opencast mining site in the northeast of the Qinghai-Tibet Plateau. The estimation is based on the field geo-temperature observation, and on the quantitative analysis for the relationship between the permafrost degradation and vegetation perishment. The field geo-temperature observation is interpreted from three aspects. First, the soils beneath the surface covered by stockpiled gangue and exposed topsoil have been greatly warmed, and experience temperature fluctuation. Second, the soil under the stockpiled gangue is warmer than that under the exposed topsoil. Third, in warm season the surfaces covered by the stockpiled gangue and exposed topsoil absorb more solar heat, leading to the warming of the underlying permafrost. But in cold season, the thermal conditions under the stockpiled gangue, exposed topsoil, and natural vegetation are approximately the same. The quantitative analysis shows that the permafrost degradation significantly leads to the perishment of vegetation, which in turn accelerates the permafrost degradation. Therefore, it can be concluded that the permafrost in the Muli coalfield is experiencing degradation.

Since the beginning of the 1990s an important increase in the mean annual air temperatures has been recorded in Nunavik, Québec, Canada. This has lead to the degradation of permafrost, which is threatening the stability of airport and road embankments in the region. In the summer of 2007 a test-site was established at Tasiujaq Airport to study the effect of three different mitigations methods: heat drain, air convection embankment, and gentle slope (8:1). The methods were constructed in the shoulder of the runway embankment, each method over a distance of 50 m. In each section thermistors were installed to study the annual variations of the thermal regime inside the different embankments. After one year of monitoring, interesting cooling trends have been observed in the different test-sections and a substantially reduced maximum thaw depth have been registered during the thawing season.

Montana State University recently completed construction and commissioning of a low temperature research facility with funding from the National Science Foundation, Murdock Charitable Trust and Montana State University. The Subzero Science and Engineering Research Facility (housed in the Department of Civil Engineering) supports a broad range of cold regions research disciplines including structural, soil, asphalt, concrete, geosynthetics, life sciences, ice/snow mechanics, wetlands, streams, transportation, and earth sciences. The simulated environments are applicable from medium/low latitude winter to polar. The facility has several world unique capabilities in environmental simulation and includes eight walk in cold laboratories, three smaller low temperature biological incubators/ environmental chambers, a low temperature epifluorescence microscope, and a temperature controlled computed tomography (CT) scanner. Each of the laboratories, while adaptable for broad application, is designed with a specific scientific focus in mind. Functions of the fully programmable individual cold laboratories include: units that provide simulation of solar and sky radiation providing realistic energy balance, a large scale structural engineering test bed, a class 1000 clean room with class 100 work area, a unit in which the liquid water phase maintains an influential environmental role, room for specimen storage, a teaching laboratory with ample room for student groups and general specimen preparation area. The paper summarizes the specific capabilities of each chamber and describes the ongoing and future research in these facilities.

The Thematic Network in Arctic Engineering and Science (TN AES) was created In June 2008 when it was approved by the University of the Arctic's Council. The TN AES focuses on the development of sustainable technologies through engineering and science in the Arctic. The goals of the TN AES are twofold: The main goal is to improve the quality of life and allow the development of natural resources in the arctic through innovations in technologies used in the construction, maintenance and operation of infrastructure, housing, public/private facilities and equipment. The other goal is to assess the impact of climate change on these technologies. This paper introduces briefly the University of the Arctic to the engineering community and then describes current and planned network activities, such as joint education programs.

Based on analyzing the interaction between coal mining and permafrost environment, an integrated indicator system for evaluating the permafrost environment of Muli mining area, a opencast coal mine located in Qinghai province, China, is proposed in this study. This system consists of three subsystems: permafrost freezing-thawing erosion sensibility, permafrost thermal stability and permafrost ecological fragility. The grade standard of environment assessment in this area, including five situations: ideal- (0.69~1.00), good- (0.52~0.69), general- (0.36~0.52), bad- (0.23~0.36) and worse-situation (0.00~0.23), was established by loading indicators' weights, which were calculated using the Analytic Hierarchy Process (AHP). Based on this method, the permafrost environment in Muli mining area was evaluated according to documented literature and fieldwork data. The index of permafrost environment, by normalizing, is 0.46. The result indicates that although coal mining only experiences a short period until now, the permafrost environment in Muli mining area is in a general situation. It means that the permafrost environment has been destroyed to a certain degree by anthropologic activities and might be further degenerated. However, at this degree, a new equilibrium could be achieved if the current environmental system is maintained and treatments are constructed against further damages.

Insights into past failures in the field of environmental engineering provide considerable value to present-day design engineers and facility owners. Through analysis and study of engineering failures, designers can learn what not to do and thereby improve design, construction, and operations. This results in reduced risk of failure and increased reliability of future projects. Engineering failures can be caused by many factors ranging from a simple case of component failure, which is easily addressed by redundant systems, to more complex situations where individual failures cascade into a catastrophic total system loss involving multiple failures. Engineering failures also can be attributed to multiple factors including judgment errors in the early planning process, engineering design mistakes, defective materials or poor workmanship during construction, or by improper operational procedures. This paper presents several examples of environmental engineering project failures in Alaska and lessons learned from them.

The proposed China-Russia Crude Oil Pipeline (CRCOP) faces significant challenges due to differential frost heaving and thaw settlement resulting from significant variations of oil temperatures along the pipeline. It is thus important to investigate the oil temperature distribution along the pipeline during the long-term operation period, the development of the frozen and thawed cylinders around the pipeline, and the variation of maximum freezing-thawing depths beneath the pipeline in the permafrost regions. The investigation is of help for selecting route, assessing and predicting the differential frost heave and thaw settlement of the Soils Surrounding Pipeline (SSP), analyzing pipeline strain/stress, designing foundation, optimizing the wall-thickness of the pipe and taking mitigative measures against the potential adverse impacts from the freezing-thawing of the SSP. In this study, a quasi three-dimensional computational model was developed to investigate the above issues considering the latest conditions. The results indicated that: 1) the compressor station and frictional heat have the significant warming impacts on the oil temperatures along the CRCOP; 2) the variation of the oil temperatures is mainly controlled by the thermal regime of the SSP, the inlet oil temperatures, the warming effects of the compressor stations and factional heat as well as global climate warming, and the volume of the pipeline's throughput; 3) the variations of the frozen and thawed cylinders and freezing-thawing depths at the typical locations along the CRCOP have been remarkably influenced by the oil temperatures, climate change, and the water (ice) content; 4) the warming effects of climate change, compressor stations and factional heat are adverse factors against abating thaw settlement in permafrost area, but they are advantageous for mitigating frost heave in the seasonally frozen ground area or taliks.

A test section was constructed for vehicle testing on frozen soils having overall dimensions of 6 m (20 ft) wide by 32 m (105 ft) long. The section had three test cells. Each test cell was approximately 7.6 m (35 ft) long by 6 m (20 ft) wide, and contained one of three different soils: clay (CL), silt (ML) and silty sand (SM). The test soils were constructed and compacted in four 0.15-m (6-in.) lifts to a total depth of 0.6 m (24 in.). Each lift was compacted with a roller to a target density of approximately 90 to 95 percent of optimum compaction (CE12) to simulate a trafficked un-surfaced road or trail. Various soil characterization tests were conducted during trafficking for monitoring the condition and homogeneity within each test soil. To characterize the test section, frost depth, soil strength, soil density, and soil moisture were measured and examined with several instruments or monitoring tools that worked well on frozen soils. This paper focuses on frost depth and soil strength measurements using various tools and relates the California Bearing Ratio (CBR) to the soil modulus (E or M_r) value using several existing correlations developed for various soil conditions.

Every year, mining and processing of Minnesota taconite (iron ore) generates about 125 million tons of byproducts, a figure that is about double the entire state's annual construction aggregate output and usage. Since the year 2000, the Natural Resources Research Institute (NRRI), University of Minnesota Duluth, has been investigating how these vast quantities of byproducts can be used for construction aggregate purposes. The NRRI has been leading a comprehensive research and demonstration program that is designed to: 1) identify new environmentally responsible and economically viable uses for Minnesota Iron Range taconite aggregate material in road construction, road repair, and other applications where crushed stone aggregate is needed; and 2) conduct demonstration projects inside and outside Minnesota. This paper presents a broad overview of the 2006–2009 research program within the context of resource sustainability, energy conservation, and infrastructure benefits. Highlighted research concepts, activities, and results related to cold climate applications include: cold-temperature testing of taconite-based hot-mix asphalt (HMA) mix designs; chemical-free deicing and all-season pothole repair using microwave technology; the development of asphalt- and cement-free pothole repair and patching compounds; and field demonstration projects that use taconite aggregates as an integral road and/or pavement component, such as in high-friction/anti-skid bridge deck surfacing treatments.

Two ABAQUS 3-D Finite Element Models (FEM) were constructed with hyper-elastic rubber tires loaded on unfrozen and frozen ground conditions (0, 7.62, 15.24, 22.86, and 30.48 cm frost depths), one contained a statically loaded tire, and the other contained a tire rolling at 8.05 km/h. The ground was constructed of multiple layers, allowing each of the respective frost depths to be adequately modeled. This was accomplished by changing the material properties in the layers to match the given frost condition. The material models used in the FEM simulations are representative of a frost-susceptible soil, which was used in full scale unpaved road tests at CRREL. The interest in this modeling is to see how the stress and displacement change as a function of frost depth as a heavy tire rolls over the surface. Stress and displacement data collected from the ABAQUS FEM simulations are compared to experimental data. The results show similar trends between the ABAQUS and experimental data for vertical displacement and vertical stress below the contact patch.

The potential of using Warm Mix Asphalt (WMA) in reducing the energy consumption of HMA is becoming more and more attractive nowadays. The goals for the WMA are to lower mixing and compacting temperatures and use the same Hot Mix Asphalt (HMA) plants to produce mixes that still meet specifications. The benefits of WMA include reduced emissions and binder aging, lower mixing and compacting temperatures, decreased energy (fuel) consumption and early traffic opening. The advantage of WMA is significant for cold-weather paving because of the slower cooling rate due to a smaller difference between production and ambient temperatures. This study presents an overview of WMA in terms of environmental aspect through a field project. Observations from the field project indicated that emissions produced during WMA construction were significantly reduced compared to HMA. Samples of HMA and WMA (with 1.5% Sasobit) were collected from the job site and tested for Dynamic Modulus and Tensile Strength Ratio to evaluate WMA's moisture susceptibility, fatigue and rutting potential. The results indicated that the moisture susceptibility of WMA was comparable to HMA. The fatigue potential of WMA was slightly higher than HMA; and the specific WMA used in this study has a lower rutting potential than HMA.

Seismic methods are useful tools to non-destructively assess the integrity of concrete. It has also been applied to characterize the behaviors of curing concrete to supply information for construction decision. This paper shows that freezing of concrete significantly affects the seismic properties of concrete. Attention needs to be paid when applying seismic method to concrete cured in cold weather. In the experimental program ultrasonic tests were conducted on curing concrete subjected to different freezing process. The results indicate while there exists strong correlation between small strain seismic wave velocity and concrete strength for concrete cured under normal conditions, such relationships do not hold if the curing concrete is subjected to freezing process. A correction accounting for the effects of ice on the bulk strength needs to be applied. This correction was found to have linear relationship with the amount of water (or ice if concrete is completely frozen). Procedures to correct the effects of freezing are proposed, which include the use of Time Domain Reflectometry to measure the water content. With this procedure, the strength of concrete in frozen status can be estimated. This information could be incorporated to determine the magnitude of Winter Load Increases in cold regions.

In northern climates, runoff from standard pavements has varying seasonal effects on the surrounding environment. Year-round runoff carries transportation associated contaminants into surface waters. During the winter and spring, deicing practices for pavements result in high levels of chloride-laden runoff that is both toxic to aquatic biota and degrades drinking water supplies. The use of pervious pavements for parking lots for new and redevelopment projects are one watershed-based strategy that can both mitigate impacts for new development and reverse impacts in areas with redevelopment. This study presents the findings from 2 pervious pavements, a pervious concrete and a porous asphalt parking lot, studied at the University of New Hampshire Stormwater Center. Winter in particular places great demands on pavements however it was observed that due to the well-drained nature of the reservoir base that freeze thaw was limited. Surface infiltration rates, frost penetration, degree of snow and ice cover, and surface friction were measured on a monthly basis to assess winter performance. Frost penetration was observed to reach depths of eighteen inches however, surface infiltration capacities remained in excess of 200-in/hr. Analysis of snow and ice cover and pavement skid resistance demonstrated that up to 75% less salt was needed for porous asphalt to maintain equivalent or better surface conditions as the reference dense mix asphalt lot. The annual median snow and ice surface cover for the porous asphalt lot was not significantly different than the reference lot with salt applications four times greater (p=0.749 @95% CI). The annual median weighted skid resistance for the porous asphalt lot was 12% greater than the reference lot with greater salt application (p=0.061 @95%CI). Pervious concrete did not demonstrate substantial salt reduction capabilities during storm events; however, ‘black-ice' formation did not occur during freeze-thaw conditions indicating possible annual reductions. Pavement color and shading were found to be major factors influencing the amount and duration of snow and ice cover on the pervious concrete lot.

While the universal force of gravity is a constant, the gravity field of the Earth varies due to anomalies within the Earth. The Earth is made from different materials of different mass with varying densities. All have an impact on the Earth's gravitational field and can thus be detected and described using gravimeter measurement systems. Ice has a density of 917 kg/m³ which is about half of the density of soil. Therefore, a large volume of buried ice is likely to generate a significant gravimetric anomaly detectable using high precision land gravimeter surveys. The objective of the study conducted at Mary River, Baffin Island, Canada was to assess the feasibility of using a high precision gravimeter to detect the presence of ground ice. Gravimeter surveys appear to be an effective technique to detect the presence of buried ice bodies along a transportation corridor such as the Mary River Railway. The technique allows detecting large ice bodies and gives best results when ice bodies are buried at shallow depths.

Cold Regions Pavement Engineering book by Guy Doré and Hannele Zubeck was recently published by the ASCE Press and McGraw-Hill. It prepares engineers to make right decisions in areas, where freezing temperatures, snow and ice, unstable soils, sparse population, long road mileage and often limited funds dictate design and maintenance actions on pavement structures. The book aimed to practicing Civil Engineers covers the unique environment, performance challenges, testing, design, management and rehabilitation of cold regions pavements including permafrost areas. Combining the latest research and proved techniques from the Northern United States, Canada and the Northern Europe, this is the first complete reference for all pavement projects in cold regions. This invited paper introduces the reader to the issues presented in the book.

Full-depth reclamation in conjunction with cement stabilization increases the strength and durability of pavement base layers when proper design and construction practices are followed. However, in adverse site conditions, construction challenges can arise. In one instance of particular interest to this research, the practice of adding additional cement, reprocessing, and recompacting an inadequately constructed cement-treated base layer within 1 day of initial compaction was specified. Because the effects of this process on density and unconfined compressive strength (UCS) have not been previously investigated, the purpose of this laboratory research was to quantify the influence of remolding on these properties with and without the addition of extra cement, A total of 12 specimens of recycled base material were compacted at the design cement content of 4 percent to the target maximum dry density of 129.0 pcf, which yielded an average 7-day UCS of 328 psi consistent with Portland Cement Association recommendations for resisting environmental degradation such as frost action. Three specimens were retained as a control group, while the remaining nine were pulverized and sweetened, again in groups of three, with 0, 2, or 4 percent additional cement after 1 day of curing. The average dry density values achieved after remolding with 0, 2, and 4 percent additional cement were 124.7, 123.6, and 126.1 pcf, respectively, corresponding to 96.7, 95.8, and 97.7 percent of the MDD. The average 7-day UCS values of the specimens remolded with 0, 2, and 4 percent additional cement were 161, 274, and 387 psi, respectively, corresponding to 49.2, 83.5, and 118.0 percent of the 7-day UCS of the control specimens. These data suggest that the 7-day UCS values achieved after remolding approach those measured for the control specimens only when approximately 3 percent additional cement is added to the material; this amount of cement corresponds to a 75 percent increase in the total cement content needed for stabilization. At lower cement contents, the remolded material would not be expected to exhibit adequate durability against frost action, and the owner would be mistaken in expecting satisfactory performance based strictly on density testing.

The tube suction test (TST) was developed for assessing the moisture/frost susceptibility of granular base materials. The susceptibility ranking is based on the mean surface dielectric value of compacted specimens after a 10-day capillary soak in the laboratory. During the process of implementing the TST statewide, Texas Department of Transportation personnel raised concerns about the reproducibility of the test procedure, leading to the ruggedness testing performed in this research. Seven factors were investigated, including air temperature, mixing and soaking water salinity, dielectric probe seating force, number of days of drying before the start of capillary soaking, aggregate fines content, water bath height, and specimen compaction energy. Sixteen specimens of each of the two aggregates, a limestone and a caliche, included in this study were treated with specific combinations of the different levels of these factors according to the Plackett-Burman experimental design. Statistical hypothesis tests performed on the data indicate that air temperature, drying time, fines content, water bath height, and compaction energy are significant for the caliche, while only air temperature is statistically significant for the limestone. Small variations in mixing and soaking water salinity and dielectric probe seating force do not apparently exert significant influence on final dielectric values in the TST. Based on the results of the research, recommendations are given for improving the interlaboratory reproducibility of the TST.

In the USA, many highway agencies have successfully implemented the Superpave^TM volumetric mixture design procedure. Yet, a number of studies have shown that the Superpave^TM volumetric mixture design method alone is insufficient to ensure reliable mixture performance over a wide range of traffic and climatic conditions. As highway agencies begin the implementation of the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG), they will be tasked with the development of local calibration factors specific to the materials, construction practices, loading regimes and environment of their region. The local calibration factors specific to the materials incorporate the test of the dynamic modulus of asphalt mixtures. In fact, the dynamic modulus of asphalt mixtures is an important input parameter for pavement thickness design. Therefore, the objective of this paper is to use the dynamic modulus of Superpave^TM asphalt mixtures in the MEPDG to predict rutting over two years and to compare the results with field rutting performance. The MEPDG prediction shows that most of the mixtures with lower design traffic levels have less rutting after two years of service. In addition, the comparison between field rutting and the MEPDG prediction shows that the MEPDG is applicable for use as a basic pavement design tool.

In 2007 the White Bear Unitarian Universalist Church (WBUUC) in Mahtomedi, Minnesota, installed a 1,412 m² (15,200 ft²) porous asphalt parking lot as the central component of their stormwater management system. Porous pavements have seen limited use in cold climates due to concerns regarding freeze/thaw damage and winter maintenance. Two years after installation, the WBUUC porous parking lot continues to perform well through the wide seasonal temperature variations experienced in east-central Minnesota. Poor draining subsoils required the porous system to be under-drained for slow release of captured stormwater. Even with poor draining subsoil, regulatory sampling data indicate total and soluble reactive phosphorus removal efficiencies may be as high as 83% to 86%, respectively. Such efficiencies far exceed regulatory requirements of 60% TP removal. Sampling results indicate total suspended solids removal efficiency may be as high as 87%. The data generally concur with historic literature sampling data which indicate porous pavement having similarly high treatment efficiency for TP and TSS. The porous pavement outperforms the water cleansing ability of traditional pond-type storm treatment systems, saves on development costs, and costs less to maintain.

Minnesota Road Research Project (MnROAD) was built in the early 1990s and has seen positive benefits related to its efforts during its initial research phase. As MnROAD enters Phase II of its existence several research projects have been initiated to help both Minnesota and its TERRA research members better understand how to build and maintain our roadway network. One area of interest is pavement temperatures and how it affects pavement performance and design. This paper will explore the variations of pavement surface types, thicknesses, base types and other design parameters as they relate to temperature. Currently no one paper has been written capture these temperature gradients throughout the pavement structure. This report provides a summary of the various temperature phenomena seen in selected pavement test cells at MnROAD. All available data was not analyzed for this report, but rather a few selected cells were analyzed for certain time periods. Therefore, the temperature extremes may not be the exact maximum or minimum for all the cells that were monitored, but should be within a few degrees and be representative to the system as a whole.

When designing road and airfield embankments over permafrost, thermal stability of the subgrade soil is often considered to be a key consideration for the overall stability of the structure. When the facility is built over thaw sensitive soil, the general approach is to attempt to raise the permafrost level underneath the embankment in order to avoid the risk of thermal degradation of thaw sensitive soils. However, in many cases, part of the active layer underneath the pavement is subject to thawing during summer. Information on the mechanical properties of thawing soils in a permafrost context is scarce and this factor is rarely taken into consideration when designing pavements to be constructed in permafrost regions. This paper summarizes the findings of a study of the mechanical properties of soils in the active layer near the Tasiujaq airstrip in Nunavik (Quebec, Canada). The study was done using the dynamic cone penetrometer and the light-weight deflectometer. The paper will also discuss the practical implications for pavement design considerations.

The purpose of this research was to identify mechanistic-empirical models published in the literature for prediction of fatigue cracking in cement-treated base (CTB) layers, identify specific pavement parameters to which each model is sensitive, and identify models that predict consistently higher or lower values than others in a parametric study involving 90 different combinations of asphalt thickness, CTB thickness and modulus, and subgrade modulus; low subgrade modulus values representing thaw-weakened conditions were specified. Four models were identified for evaluation: 1) American Coal Ash Association, 2) Australian, 3) South African, and 4) Uzan. Computer software was utilized to calculate the critical stresses and strains needed to determine CTB fatigue life, and statistical procedures were employed to analyze the data. Within the ranges of values investigated in this study, the Australian and Uzan models are most sensitive to the evaluated factors, while the American Coal Ash Association and South African models are least sensitive. In addition, the data clearly indicate that the Uzan model most frequently predicts the highest values of CTB fatigue life, while the South African model most frequently predicts the lowest values. Field performance data are needed for evaluating the accuracy of these models, the results of which vary widely for the studied conditions.

Spring Load Restrictions (SLR) are commonly used as a pavement preservation strategy in cold regions. Implementation of SLR has been found to bring about significant economic benefits by extending the pavement service life. Monitoring the freeze/thaw status of subsurface soils is crucial for making sound decisions on SLR implementation. Current tools to assist this decision are limited, as they are unreliable and unable to provide timely data. As a result, the decisions on starting and ending of SLR as well as the magnitude of load restrictions are highly subjective. There remain room to optimize the benefits of this important transportation policy. This paper introduces the development of an innovative sensor for monitoring freeze-thaw status of subsurface conditions. This sensor possesses distributive sensing capability. Laboratory evaluation shows the sensor signal clearly indicate the infiltration process. The sensor was deployed at MnRoad, the world's largest and most comprehensive outdoor roadway laboratory. It has demonstrated excellent signal quality. Sensor signals provide clear information to identify the on-set and evolution of freezing and thaw process. Besides, the sensor signal indicated the subsurface thaw process accomplished about one month earlier than when the SLR is lifted. This sensor is promising to provide sound decision-support for SLR.

With the construction of four new test cells in 2008, the Minnesota Department of Transportation (Mn/DOT) now has six unique pervious pavement test sections at the MnROAD test facility. Recorded temperatures in the pervious pavements and subgrades were compared to impervious Portland Cement Concrete (PCC) test sections over the same time interval. It was found that the subgrade in pervious PCC and Hot Mix Asphalt (HMA) was up to 4 °C warmer in the winter than impervious PCC pavements. The frost depth in an impervious PCC pavement was found to be 45.7 cm deeper than in a pervious PCC pavement of similar thickness. One pervious pavement test cell experienced 60% less freezing cycles over a three year interval than impervious PCC pavements of similar thickness. The air trapped in the pavement voids was suspected to be the main reason for the reduced number of freeze-thaw cycles by creating an insulating effect. In another pervious pavement, entrapped air within the base material may also insulate the pavement from the subgrade.

Warm-mix asphalt (WMA) is a group of technologies that allow for the placement of asphalt at production temperatures 35°F–100°F lower than traditional Hot-mix asphalt (HMA). Some of the benefits for using WMA are that it lowers fuel consumption, lessens the aging of the asphalt binder, decreases the production of greenhouse gases, allows for the placement of asphalt plants in more restrictive areas, and improves worker conditions. First used in Europe, WMA was introduced to the U.S. with a European scanning tour in 2002. In 2004 the first field tests in the U.S. were constructed, with the first production paving jobs in 2006. Warm Mix Technology is divided into three distinct classifications based on the mechanism used to produce the end product. In one class, foaming, small amounts of water are mixed with the hot asphalt oil. A second process uses organic additives or waxes to decrease the viscosity of the oil. The last class use chemicals or surfactants to aide in the coating of the aggregate at lower temperatures. All three processes have been used in cold weather climates. A surfactant was chosen for Crow Wing County Road 108. Most surfactants require little if any plant modifications when compared to a foaming process in which the modifications could be as simple as adding another bin to a rap feeder or as complicated as adding manifolds and injectors to the plant. The use of a wax was rejected, as one of the ways to get a cost comparable product for this project was to substitute a warm mix product using PG 58-28 oil for a hot mix product using PG 58-34 oil. Research indicated that one of the benefits of warm mix using the foaming or surfactant process is that they generally perform better than the waxes for thermal cracking. On August 19^th of 2008 2913 tons of WMA and 272 tons of HMA were placed on Crow Wing County Road 108 by Anderson Brothers Construction Company of Brainerd. A level 2 gyratory mix design was used incorporating Evotherm 3G in the asphalt binder. The additive was added at the Flint Hills refinery in Minneapolis at a rate of 0.5% by the weight of the binder. The product arrived at the paving plant ready to use, requiring no modifications to the plant or the paving equipment. During production the only change made to the normal testing procedure of the mix was the temperature at which the gyratory samples were made. The oil met all the requirements of a PG 58-28 oil and the mix met all of the requirements of a Level 2 gyratory design. The binder was cut 0.1% from the HMA design to bring the production air voids in the WMA up to the desired levels. The densities of the road cores of the WMA (ave. 92.7%) were found to be slightly below that of the HMA (94.1%) but still at a respectable level for a 2 inch lift on a 5 ton road over gravel. Answers that will come over time are whether or not WMA will perform better than HMA for thermal cracking, will it will have a longer life span and will prices become comparable to HMA. Some other countries currently believe the answers are "yes" and are willing to pay a higher price today to realize cost savings in the future.

This paper focuses primarily on the mechanics of rail seat abrasion with an emphasis on cold regions due to the severity of the issues in those climates. The investigation includes a synthesis of the best practices used to mitigate this type of failure. Also included is an exploration of alternative materials with good abrasion resistance for use in the rail seat region. The objective of this research is to evaluate materials and/or methods to eliminate the problem of railseat abrasion.

At present, crushed-rock embankment has been widely utilized as a method for avoiding thaw settlement of roadbed in the construction of Qinghai-Tibet Railway of China. The ballast layer and crushed-rock layer can be regarded as porous media in railway embankment. It is windy on the Qinghai-Tibet Plateau, so that the crushed-rock embankment is often covered by sand or snow on its surfaces and a special closed space is formed in its crushed-rock layer. In this paper, in order to research the cooling effect of crushed-rock embankment on the underlying permafrost under the closed condition, based on the special climatic and geological conditions of Qinghai-Tibet Plateau, a numerical representation of the unsteady two-dimensional continuity, momentum and energy equations of thermal convection for incompressible fluid in porous media is used to analyze the temperature characteristics of closed crushed-rock embankment for 50 years. The results indicate that, under the assumption that the air temperature will warm by 2.6 °C in the future 50 years in the areas where the present mean annual air temperature is –4.0 °C, when the crushed-rock embankment is covered by sand or snow, it can still protect actively the underlying permafrost; However, with the augment of embankment height (embankment fill thickness on crushed-rock layer), its cooling effect becomes weak.

Are represented the results of full-scale searches, calculations and theoretical studies of the state of the large construction of those subjected to deformations in connection with the disturbance of geocryological and geo-ecological situation. Are revealed differences in the stability of the construction, elevated on different types of foundations in by Norilsk industrial region. The influence of the different types of the negative technogenic effects including heating and engineering actions is established. The procedure of observations and calculations for the forecast and undertaking the necessary measures is presented. During the last decade, the problem of stability of buildings and constructions in permafrost zone has been significantly aggravated. The complex research in order to establish the reasons of decreasing of bearing capacity of perennially frozen bases have been carried out. In has been found out that the main reasons of deformations are negative technogenic effect on the geocryological and geoecological environment while the global climate warming up effect on the bearing capacity of frozen bases hasn't been stated. Are developed and experimentally tested thoroughly complex engineer operations on the stabilization of situation in by Norilsk region, and also the specific technologies on strengthening of the frozen soils of bases. Such basic measures are: 1) the application of artificial cooling of soils, using liquid and vapor-liquid thermosiphons together with cooling of near-surface ground layer by air; 2) the cementation of local talics; 3) static depression of piles into the soil by powerful jacks, and also an improvement in the contact of foundations with the permafrost species; 4) new technologies of padding and reconstruction of underground collectors for the engineering communications; 5) increasing of ventilation of cold bases; 6) the equipment of mounds by antifiltration screens; 7) monitoring of the snow cover regime in built up areas; 8) arrangement of the run-off of rain and flood water. Reliability and safety of the operation of objects ensure accounting for a change in the geocryological situation together with the effective methods of construction of buildings and facilities on the pile foundations.

Many researches and engineering practices about the Qinghai-Tibetan Highway have proved that the thermal stability of the roadbed is the key problem of the roadway stability in permafrost regions. Beginning with the concept of critical heights of roadway embankment in permafrost regions, we conducted an in-situ experiment along the Qinghai-Tibetan Railway and a series of numerical analysis about the reasonable heights of roadway embankment on the Qinghai-Tibetan Plateau. The main conclusions are as follows: (1) the in-situ experiment shows that the rise of permafrost table under the embankment is not in proportion to the increase of embankment height. When the embankment is higher than 4m, the rises of permafrost table decrease with increasing embankment height. (2) the numerical analysis illustrates that, under the condition of mean annual air temperatures (MAAT) at –3.0, –3.5, –4.0, –4.5°C, respectively, the minimum embankment heights for asphalt pavement should be 8.24, 5.32, 3.11, 1.67m, and the maximum embankment heights should be 2.79, 3.4, 3.71, 3.99m; otherwise, the minimum embankment heights for gravel pavement should be 1.84, 0.55, 0.42, 0.42m, and the maximum embankment heights should be 3.42, 3.90, 4.13, 4.39m. (3) the critical values of MAAT for the existence of the critical embankment heights are –3.9°C for asphalt pavement and –2.8°C for gravel pavement.

Jurisdictions in Canada and the northern United States apply spring load restrictions (SLRs) to low volume roads to mitigate damage to these roads during spring thaw. Ideally, the SLRs should commence when the thaw front has begun to penetrate sub-base materials, and end when the pavement system is completely thawed (Andersland and Ladanyi, 2004). Methods involving visual observations, field testing, prescheduled dates and empirical models are currently being used to apply SLRs. These methods, however, do not readily allow variations in climatic conditions and pavement system properties, such as soil type and water content, to be accounted for in a comprehensive manner. To this end, thermal numerical modeling is being conducted for the purpose of developing guidelines to apply SLRs. Time variations of frost and thaw depths were simulated using the finite element thermal model TEMP/W (by GEO-SLOPE International Ltd.) and are compared with measured frost and thaw depths at an instrumented site in northern Ontario. A particular focus of this work is on the thermal boundary conditions applied at the upper and lower boundaries of the thermal model. Modelling results to date indicate that penetration of the frost front over the winter can be simulated fairly well, with a good match to the measured results. Modelling the thaw front penetration was found to be quite dependent on the upper thermal boundary condition. An approach in which an "n-factor" is used to estimate pavement surface temperatures from measured air temperatures best simulates the measured progression of the thaw front. A floating reference temperature approach, to better account for increasing solar gain during the spring thaw period, is also examined.

Dust produced from unpaved roads in rural Alaska is impacting the quality of life in many Alaskan and other villages in cold regions. Not only does dust emanating from unpaved roads cause respiratory ailments, but also impacts subsistence food storage and sources as well as safety since dust impacts visibility on village streets. Loss of fine particles also greatly impacts the quality of road surfaces creating increased maintenance costs. Replacing the fines content in unpaved road surfaces is costly owing to the lack of suitable material and equipment in many villages. The expectation for many communities is that paving their roads will solve their problems. In some cases this may be possible. In many rural environments, however, lack of suitable material or cost prohibitive sources, unsuitable foundation materials or inability to maintain the improved roads preclude pavement as an option. A suitable option for many rural villages may be dust control palliatives and institutional controls. However, there is little consensus on how to identify and measure the effectiveness, economics, and environmental impacts of dust control approaches that are compatible with the subsistence lifestyle common in remote rural communities in Alaska and other cold regions. Our objective in this ongoing study is to evaluate different dust control methods used in rural Alaska. These dust control methods include various synthetic polymer type palliatives, calcium chloride, and institutional controls. This paper presents our current efforts to quantify and qualify the effectiveness of dust control measures. Of the different dust control methods, the Alaska Department of Transportation and Public Facilities (AKDOT&PF) has the most experience with calcium chloride (CaCl₂). Salts such as CaCl₂ (magnesium chloride is another common dust control salt used by others) control dust by adsorbing and retaining moisture in the aggregate surfacing material. These compounds are most effective at suppressing dust when the relative humidity is greater than around 30 to 40 percent (Rushing and Tingle, 2006). During morning hours when relative humidity is typically high and temperatures are low, moisture is retained in the salt treated road surface. As the temperatures rise and relative humidity drops in the afternoon, moisture losses by evaporation from the treated road surface are reduced in comparison to untreated road surfaces. Synthetic polymers comprise several different compounds that promote soil particle binding. Several different products are provided by vendors under the names EK-35, EnviroKleen, Durasoil among others. The compositions of these compounds are typically proprietary. The fraction of loftable fine particles is reduced by the aggregating action of the palliative. Anyone who has driven on unpaved roads has experienced the effect vehicle speed has on the quantity of fine particles lofted by the vehicle. Control of speeds on rural roadways when possible is one of the least expensive means to control dust.

The highway embankment is about 800 km (500 miles) north of Winnipeg, Manitoba, Canada in an area where permafrost is degrading rapidly. Soil sampling and installation of instrumentation (temperatures, settlements, lateral deformations and pore water pressures) was undertaken in October 2008. The paper describes the past performance of the embankment, the instrumentation that has been installed, data from the instruments during the first winter of operation, and initial results from the laboratory testing program.

Urban universities have to address problems related to safety, security and operations of activities occurring within the perimeter of their campuses. The complexity of the problem increases especially for campuses located in an open access neighborhood such as Concordia University in Montreal. A microscopic simulator is used to evaluate potential benefits of building a new underground tunnel in the downtown campus of Concordia University. It was found with 95% confidence that the average delay of vehicles is considerably reduced for all approaches. Also, it was found that total pedestrian travel times can be reduced by up to 90 minutes within the peak 15-minute period under the assumption that half of the pedestrian activity is re-routed through tunnels. In general, it can be concluded that the availability of the underground pathways has operational and safety benefits, by minimizing pedestrian-vehicle interactions and providing a more convenient environment for pedestrian activity within the campus perimeter.

In late 2006, the New Hampshire Department of Transportation, NH DOT, initiated a study to develop a Real Time Spring Load Restriction (SLR) Methodology to guide the Maintenance Districts in their management of spring load restrictions by identifying the beginning and duration of the spring thaw period. The study includes selection of test areas, purchase and installation of instrumentation, collection and analysis of data from the instruments and development and implementation of the methodology, Eaton, et al (2009), discuss details of the project. In this paper we discuss the initial procedure, the installed instrumentation, observations from the instruments, and refinements indicated by the observations and initial analysis of the data.

The results of scientific researches and engineering calculations of rational structures parameters of highways are presented in the paper. All the calculations and researches done were carried out relatively to a highway section in the Russian Far East. This road is being built in severe climatic and complex engineering and geological conditions. This is the area of permafrost occurrences and widely spread deep season freezing. The usage of a geosynthetic integral two-axis gird in the structure allows to lessen considerably the volume of expensive hard mineral volcanic filling of high quality. Numeric modeling of the structure behavior was done using a programming geotechnical complex, an "FEM model". This allowed to give a quantitative and qualitative assessment of freezing and thawing processes in conditions of annual cycle construction. Effective measures to provide operational reliability for the rational engineering solutions for highways in Northern territories of the Russian Far East were worked out on the basis of the achieved results.

In the fall of 2006, the State of New Hampshire Department of Transportation (NHDOT) began a two - year study to develop a Real Time Spring Load Restriction Methodology. The methodology is intended to guide the Maintenance Districts in their management of spring load restrictions by identifying the beginning and duration of spring thaw. Two methods will be used to determine how long load restrictions will be needed after the date of actual thaw: frost tube readings and computer model forecasting. A total of nine sites in the central part of the state were instrumented with frost tubes, water wells, subsurface temperature and moisture sensors, and weather stations. Falling Weight Deflectometer (FWD) tests were conducted at those sites from January 2008 through June 2008 with an additional test in August 2008 and another in October 2008. The U.S. Forest Service is continuing its work with the current developer of the Enhanced Integrated Climatic Model (EICM), which is embedded in the Mechanistic Pavement Design Procedure (MEPDG). It is proposed to use the EICM (isolated from the MEPDG) with the 7–10 day forecast temperatures to predict thaw. This paper describes the overall project, data collected to date, and preliminary results.

Three instrumented test sections of sand, silt and clay, were constructed to monitor the impact of frost layers on vehicle induced stresses and to assess the performance of the sensors used to measure such stresses. One of the instruments used to measure in-situ stress is the soil Stress State Transducer (SST), which was installed at 12.7cm depth within each of the test soils. The SST was designed by the USDA Agricultural Research Service, National Soil Dynamics Laboratory and the Auburn University Department of Agricultural Engineering, and has been used in many studies on vehicle induced stresses in agricultural soils, but not previously in freezing soil. Each SST consists of six semiconductor pressure transducers installed in a small sphere. Soil displacements, temperature and moisture and strength profiles were also monitored. Trafficking of the test sections was performed at frost depths ranging from zero to over 50 cm. The SSTs functioned very well in frozen ground. The signals clearly showed the passage and sometimes the bow wave in front of each tire, and then the large vertical pressure spike as each tire passes over the sensor. The stress magnitudes diminish as the ground freezes above the sensors and then decrease further as the frost envelops the entire sensor.

In-situ bioremediation is one of the effective technologies for cleaning up petroleum-contaminated sites. To improve efficiencies of conventional bioremediation processes, biosurfactant treatment has received much attention due to the surface-activity, biodegradability and low toxicity of biosurfactants. In this study, an integrated mathematical modeling system was developed for simulating the biosurfactant-enhanced bioremediation (BEB) processes under typical Canadian site condition. The model included modules of multiphase multicomponent flow and transport, biological degradation, and biosurfactant-enhanced remediation. A pilot-scale physical modeling system, with Rhamnolipid being used as biosurfactant, is designed to simulate the BEB process. The study results demonstrated that the developed mathematical model is effective in examining the coupled effects of biodégradation and biosurfactant-enhancement within a multiphase multicomponent transport framework, and can be used for supporting management of petroleum-contaminated sites under cold climate conditions.

Cold weather changes wastewater treatment. Biological processes slow down, making treatment less efficient. Ice layers form on the top of exposed tanks, affecting the operation of these tanks, and potentially affecting any equipment located on the surface. Layers of ice can coat enclosures, equipment, and even access ways, making access to maintenance of treatment processes difficult, or even hazardous. As Engineers, we need to keep these things in mind during our design. Not only do we need to make sure that we are providing enough tank volume to allow for adequate treatment during these periods of slowed biological processes, we need to ensure that we are providing an environment in which the operators can successfully and safely operate, and maintain their systems. The City of Chatfield's Wastewater Treatment Facility deals with cold weather issues every year. As with all treatment facilities designed for cold weather operation, the design of the facility took into account the larger tanks that are needed in the cold weather to make up for the slowed biological processes. The design discussion included questions like, "how will this work in the winter?" and, "how will we service this equipment in the winter?" However, even with this questioning, there are still a number of cold weather issues that the facility has to deal with, some of which have been solved through operational changes, other which have been solved through the addition or modification of equipment.

Frost heave is the heaving of the ground surface when frost-susceptible soils, in conjunction with high water table or surface water infiltration, freeze. This paper discusses the foundation design strategy for frost-heave forces in areas with substantial frost depths. Only foundations in seasonal frost areas are discussed. Performance of foundations in permafrost and design of pavement and roads are beyond the scope of this paper. As a real case study, the preliminary study and approach that were implemented for the foundation design in a recent project in Fort Saskatchewan, Alberta, Canada are presented. After preliminary studies, the project decided to implement three primary approaches for foundation designs: (i) Installation of compressible void forms underneath pile-supported foundations; (ii) Installation of 200mm rigid Styrofoam insulation to limit the depth of frost penetration, underlain by 300mm of non frost-susceptible granular fill material, with either soil supported or pile foundations below; and (iii) The use of screw piles with a bond breaker on the shaft above frost line.

In this study, ice force on bridge piers during collision was investigated. Field test was performed on the Huma River Bridge in northern China and laboratory test was performed on ice specimens to measure the ice compressive strength at various temperatures and strain rates. Test data was analyzed using the Universal Global Optimization (UGO) technique. Relations for ice compressive strength as functions of ice temperature and strain rate were obtained. The temperature distribution in a floating ice sheet was measured continuously for three days using Cu50 temperature sensors. The temperature distribution was observed to be nonlinear, with the lowest temperature in the middle and increased temperature toward the surfaces. A weighted-average temperature in the ice thickness was proposed to be used to determine the ice strength. Using ice strength determined by the obtained relations, the ice forces on the Huma River Bridge piers was calculated. Comparative analysis between calculated results and field tests was carried out. The computed ice force using the equation for Heilongjiang province with the ice strength determined by the obtained relations showed good agreement with the measured values.

Stochastic process modeling of snow loads has been applied in structural reliability analysis. However, the snow load is usually modeled by a, random variable with a specific distribution (e.g., Lognormal distribution) in combination with a Bernoulli pulse process. In this paper, the Filtered Poisson Process (FPP) is used to model the snow load. Simulated records are compared with weather records of Stampede Pass, WA. and Buffalo, NY, obtained from the National Climatic Data Center (NCDC). The FPP model is demonstrated to be versatile for both heavy and light snow load areas.

Sheet pile and other steel structures installed in the Duluth, Minnesota and Superior, Wisconsin shared harbor are corroding at an accelerated rate compared to other Great Lakes harbors and ports. The harbor is located on Lake Superior and fed fresh water by the St. Louis and Nemadji Rivers. Originally discovered in 1998, the cause and potential solutions to the phenomenon have been investigated through a series of studies that carry on through today. An expert panel convened in 2004 to make an initial assessment of the extent and cause of the accelerated corrosion, as well as make recommendations for future testing necessary to identify and resolve the problem. Subsequent studies based on panel's recommendations have 1) determined the extent and rate of corrosion on steel structures in the Duluth / Superior Harbor (DSH) and established a long term corrosion rate monitoring program, 2) determined one possible cause directly influencing the accelerated corrosion through extensive biological testing, 3) established long term testing of coating and cathodic protection systems including the study of different coating's abilities to resist ice impact and abrasion experienced in cold region waters, 4) initiated long term full scale testing of alternative pile protective systems designed for cold regions, and 5) have shown that the accelerated corrosion is not only isolated to the DSH and has been found in other ports, harbors and small marinas within the confines of Lake Superior. Results from protection systems testing to date have identified several attractive coating and alternative protection systems that have showed to be resistant to ice impact and abrasion while preventing further corrosion of the steel structures. Future plans include the continued monitoring of existing long term tests as well as the initiation of further coating and alternative technology trials. Results of all trials will be published for utilization in the DSH and other cold region harbors.

This paper summarizes recent laboratory and field data studies on thermal performance of stress-laminated timber highway bridges. Concerns about the reliability of stress-laminated deck bridges when exposed to sub-freezing temperatures triggered several investigations. Two laboratory studies were conducted to study the effects of wood species, preservative, moisture content, and temperature variations on pre-stressing bar forces (critical factor) in stress-laminated decks. The field performance of several stress-laminated timber bridges were monitored within a Nationwide Timber Bridge Monitoring Program, a cooperative effort by the U.S. Forest Service, Forest Products Laboratory and Federal Highway Administration. Bar-force and temperature data from a subset of bridges were continuously monitored for a period of 2 to 5 years with remote data acquisition systems. Significant pre-stressing bar-force losses were observed in laboratory studies when the moisture content of deck laminations were at 30 percent and greater and the deck temperature reached 0°F (–18°C) and below. The field study concluded that the magnitude of cold-temperature induced bar-force losses were not significant enough to warrant special considerations in the U.S. bridge design code. However, it may warrant special considerations in cold weather regions outside the United States whenever deck lamination moisture contents exceeding 20 percent are combined with ambient temperatures remaining below 0°F (–18°C) for extended periods of time.