Journal of Cold Regions Engineering

This paper investigates the severity of pothole problems, conducts a critical assessment of current maintenance practices, and identifies resources available for pothole repair based on the results from a questionnaire survey of six provincial transportation agencies in Canada. The survey outcomes indicated a greater percentage of moderate to highly severe potholes in the study area. Freeze-thaw cycles were identified as the most influential factor in pothole formation. A large portion of pothole repair operations are conducted in the summer period. The frequently used patching materials were conventional cold mix, hot-mixed asphalt, Quality Pavement Repair, and Innovative Asphalt Repair. The throw-and-go method is commonly used for pothole repair operations in all seasons. The durability of a winter-repaired patch is significantly less than that of summer. Raveling, edge disintegration, and cracking are the most concerning distresses of patch failure, which could be a result of inadequate stability, adhesion, cohesion, and stripping potential of patching materials.

Snow accumulated on a train underframe may detach itself in places where rail discontinuity causes an excitation to the train. In turnout areas, this may cause serious problems when snow buildup from beneath the rolling stock drops into the gap between the switch blade and the stock rail and disrupts the turnout operation. This paper studies the connection between rail discontinuities and snow dropping off the train underframe by means of a theoretical survey and monitoring systems in train underframes and turnout areas. The first measurement setup presented in this paper enables experimental insight into the correlation between snow detachment patterns and excitation-created accelerations of the rolling stock. The second measurement in turnout areas reveals that the snow-detaching behavior is clearly dependent on the outdoor air temperature and the velocity of the rolling stock.

In the northern regions, ice accretion on bridge cables poses serious risks to the structure as well as to vehicular traffic when ice falls from the cables onto the road. The detection and quantification of ice formation allows the anticipation of ice falls and increases the safety of the structures. In this paper, an ice accretion detector was developed on the basis of the statistical modeling of vibration response signals. Three different methods were tested on the acceleration signals obtained from a bridge cable. The methods included the Fourier transform analysis, the autoregressive model, and the continuous wavelet transform analysis. Damage-sensitive features (DSF) were extracted from these models and tested with the data collected from a laboratory experiment conducted in a climatic wind tunnel. It was found that all three DSFs were correlated to ice accretion. The wavelet-based DSF had the highest correlation, resulting in the largest change of the DSF value and in the smallest estimation error.

Paving interlayers have been used in asphalt concrete (AC) overlays in a variety of design and construction situations for more than three decades. In cold regions such as Alaska and other northern states, AC pavements are more prone to distresses caused by climatic extremes; therefore, additional requirements should be satisfied when an interlayer is selected for a specific paving job. Although paving interlayers have been continuously improved for better performance, laboratory evaluation and performance data are still needed to verify the feasibility of using the existing and some newly developed paving interlayers in cold regions, especially for their cracking resistance. This paper presents a study to experimentally evaluate the cracking resistance of asphalt mixture reinforced with selected paving interlayers that are added as an entire layer and/or as interlayer strip. Laboratory tests included dynamic modulus, overlay, and direct tension tests conducted on asphalt mixture specimens by an asphalt mixture performance tester (AMPT). Pavement structural analysis and finite-element method (FEM) analysis were further performed to simulate and evaluate the performance of different paving interlayer-reinforced AC layers in the field. The laboratory testing results identified the high potentials of specimens reinforced by an entire layer or a strip of selected paving interlayers in improving pavement’s reflective cracking resistance. The interlayer strip was found capable of hindering the propagation of cracks and changing the path of crack development. The bonding between the interlayer and asphalt mixture may largely affect the effectiveness of the interlayer for crack resistance. Both pavement structural analysis and FEM simulation identified the benefits of using the selected paving interlayers.

Open graded friction course (OGFC) is used to reduce noise, improve friction, and for faster drainage of surface water of an asphalt pavement. However, OGFC’s contribution to low-temperature transverse cracking has not been documented yet in literature. This study investigates whether OGFC affects the low-temperature transverse cracking performance of asphalt concrete (AC). Cylindrical samples were prepared in the laboratory using an OGFC mix and a conventional AC mix in New Mexico. Laboratory tests, examining dynamic modulus ($E^{*}$), indirect tensile strength (ITS), coefficient of thermal contraction (CTC), and creep compliance, were conducted. Low-temperature transverse cracking potentials of both OGFC and AC were evaluated using the test data. Results show that OGFC has less $E^{*}$ and CTC, higher ductility and creep compliance than the AC mix. This means that OGFC is less susceptible to low-temperature transverse cracking compared to the AC mix. This finding is validated using the field survey data. It is found that OGFC prevents the low-temperature transverse crack growth in asphalt pavement. Therefore, OGFC can be considered a good potential material to resist low-temperature transverse cracking, especially in cold regions.

This research identifies the sustainable construction techniques appropriate for remote and cold regions; some of the techniques also apply to operations and maintenance. This research developed a method to extract practical knowledge from industry experts with field construction experience in remote cold regions and to categorize and present the knowledge to the contractors and designers who might find it useful. First, the vast body of literature regarding green construction in warm regions was reviewed, and the information was identified that might be applicable to cold and remote regions. A hierarchal taxonomy was developed to categorize the information and reduce it to a form useful for presentation to engineering and construction managers. Then, 22 engineering and construction managers, all familiar with cold regions and remote projects, were interviewed, and the information and the taxonomy were reviewed with them. This process resulted in a set of preliminary guidelines, which was presented at two meetings of construction experts, after which the preliminary guidelines were revised slightly. The final set of guidelines, approximately 160 suggestions and notes, was used to develop a module for university construction management classes, in which knowledge gathered from the practical experts is transferred to the students.

Seasonal freeze-thaw cycles and frost penetration depth in cold regions can be key contributors to pavement damage, and it is important as part of design practice to account for detrimental freeze-thaw conditions in the foundation layers. Empirical and numerical models have been developed to estimate frost penetration beneath pavements. This case study applies the modified Berggren equation as well as three simple empirical models to estimate frost penetration for multiple pavement conditions. Each of the test locations had an array of buried temperature sensors and different pavement structures. The simple empirical equations performed poorly, but the modified Berggren equation had more promising frost penetration depths. Modified Berggren equation calculations were performed with a computer program. The air and ground surface temperatures were monitored to verify influences of the n-factor transferring air to surface freezing index. Different geomaterial properties were used in calculations to explore ways to improve estimation accuracy. Results indicate that pavement type, foundation layer conditions, and local climate affect the computer program’s frost penetration estimates. Including site-specific information improves the accuracy of frost penetration predictions.

In the context of climate warming, damage to road pavements and embankments in permafrost regions caused by thawing of underlying permafrost severely reduces the serviceability of roads. In this study, 10 types of asphalt pavement damage were measured every kilometer along the Qinghai–Tibet Highway (QTH), from Kunlun Mountain to Tonggula Mountain (approximately 440 km in permafrost regions). Based on observed data and embankment geometry along the QTH, and information about the characteristics of the permafrost, aspects of pavement deterioration are analyzed and discussed. The three most common forms of pavement damage in the permafrost regions are transverse cracking (TC), potholes, and longitudinal cracking (LC), observed in 87, 64, and 57% of the study section, respectively. About half of the damaged pavement was also affected by block cracking (BC) and alligator cracking (AC), in addition to LC and TC. Results also showed that pavement damage in the degrading permafrost regions was closely related to the underlying permafrost characteristics and embankment geometry. Damage from settlement and patching were more severe in sections with high ice content than low ice content. All the above forms of damage increase exponentially with higher underlying permafrost temperatures. Because of the significant thermal effects of sunlit/shaded slopes, BC, LC, and TC cracking is closely related to roadway orientation, with the most severe cracking damage observed in roads oriented approximately east to west (E–W). Also, more LC was seen in sections of greater embankment thickness, which exacerbates the sunlit/shaded thermal effect.