The use of high-inflation pressure and heavily loaded tires on aircraft induce high stresses at the surface of runway pavements. High compressive, tensile and shear stresses at or near pavement surface are likely to induce rutting and surface-initiated fatigue cracking (top-down cracking) in asphalt concrete. Tire-pavement interaction has been extensively studied using finite element modelling but has not been experimentally documented due to the limitations of conventional pavement instrumentation technology. During construction cycle 7 (CC7), five flexible pavements were constructed. Four of the five test sections include 200 mm, 250 mm, 300 mm and 375mm of P401 hot mix asphalt (HMA) concrete over a P154 subbase (thickness varying between 890 and 965 mm) resting on a CBR 5.5 subgrade soil. The proposed paper describes experimental investigation of near-surface strains induced under Heavy Weight Deflectometer (HWD) and aircraft tires using an innovative instrumentation technique based on fiber optic sensors. Four “strain plates” supporting an array of 24 Fabry-Perrot fiber optic sensors were retrofitted in the HMA layers of four test sections at the Federal Aviation Administration (FAA) National Airport Pavement Test Facility (NAPTF) in Atlantic City, New Jersey. The proposed paper will describe the strain plate technology and the installation of the sensors, and results of pavement response under the HWD and aircraft wheel loads).

An embankment section along the Inuvik-Tuktoyaktuk Highway in the Northwest Territories, Canada, was instrumented with temperature sensors during its construction in April 2015. The embankment is founded on continuous permafrost and was built using compacted frozen fill. A numerical model was previously developed in a commercially available finite element software to simulate the thermal behaviour of this embankment. The model was calibrated using temperatures available in the embankment fill and underlying foundation between April 2015 and August 2018, followed by thermal performance forecasting for near-term (i.e., less than 30 years) and long-term (i.e., to 2100) climate scenarios using CMIP5 projections for Canada. Since the original thermal assessment for this site, 5 years of additional data have been recorded from the temperature sensors. The next-generation CMIP6 climate scenarios have been developed. This paper aims to evaluate the temperature data collected between 2015 and 2022 with the forecasted temperatures using the next generation climate scenarios. The results of the climate scenarios presented in this paper provide an insight into the opportunities and risks involved in maintaining embankment thermal stability and impede permafrost degradation.

Road infrastructure built over permafrost is increasingly vulnerable to climate change, with seasonal thawing causing significant degradation in mechanical performance. Variations in moisture content, active layer thickness, and freeze-thaw cycles can compromise structural integrity, especially in granular embankments without asphalt surfacing. Understanding how these environmental changes affect stress distribution and stiffness is critical for maintaining long-term road stability in northern regions. This study monitored the mechanical response of a granular road embankment along a permafrost-affected corridor during the thawing seasons of 2022 and 2024. Field instrumentation, including pressure cells and strain gauges installed in site, captured stress and deformation data under controlled truck loading at multiple speeds. Seasonal site visits were conducted in June, August, and September each year. Elastic modulus was calculated from stress-strain relationships and interpreted alongside temperature and moisture content profiles obtained during testing. The results revealed strong seasonal trends: in 2022, the modulus increased from 86.3 MPa in June to over 300 MPa in September, indicating progressive stiffening as the embankment dried. In 2024, modulus values were significantly lower across all months, suggesting deeper thaw penetration and a weaker subgrade layer. Higher stress magnitudes and pulse widths in August reflected dry, compacted conditions, while June responses showed energy dissipation in wetter, softer soils. These findings demonstrate the impact of permafrost degradation on embankment stiffness and stress transmission, emphasizing the need for improved monitoring and design adaptations in cold regions.

The construction of transport infrastructure in permafrost regions inevitably affects the hydrology of the watershed it overlaps by impeding water drainage on the land. The geomorphological, geotechnical, and geothermal consequences of heat transfer between water and the ground, resulting from the convergence and channeling of runoff and subsurface water around infrastructure, are still poorly understood. Consequently, no physically based quantitative design criteria have been clearly defined to date for the drainage systems currently in use. Through field observations and data collected in this research, drainage design tools based on a Peclet number adapted for Arctic soils and a Nusselt number for packed beds of fine particles were developed to: 1) limit heat advection by subsurface flows along and beneath transportation infrastructure, 2) determine the minimum installation distance required between an interceptor ditch and the embankment toe and 3) assess convective heat fluxes at the embankment toe. The drainage design tools proposed were validated using observations and data from previous studies conducted at the Beaver Creek road test site in the Yukon and were applied to the conditions of an additional test site located near the Alaska-Yukon Border in Canada. This research project is the first to provide design tools and charts for drainage systems built in permafrost regions.

Frost action is a leading cause of premature failure and pavement degradation in cold climate regions, necessitating robust design considerations. Although mechanistic-empirical (M-E) principles have become the accepted standard for modern pavement design and analysis worldwide, the practice of accounting for frost effects frequently reverts to outdated empirical methods or rules of thumb. This disconnect between sophisticated general design and simplistic frost consideration leads to inaccurate performance predictions and suboptimal, less durable pavements. This paper examines and critiques the limitations inherent in current cold region design practices, specifically focusing on the insufficient application of fundamental mechanistic principles to complex frost phenomena. The discussion advocates for the urgent adoption and deeper integration of M-E methodologies to accurately model, predict, and ultimately mitigate the detrimental impacts of frost action on pavement infrastructure.

This paper investigates a case study of ground thermal conditions underneath the access road embankment at Tasiujaq, Nunavik, Canada. A two-dimensional finite-element model was developed to analyze the heat transfer process and predict its long-term thermal regimes, considering a climate warming rate of 0.9 degrees C per decade. The simulation results indicate that the side slopes are thermally unstable, and climate warming is exacerbating the unstable condition. Two engineering solutions have been proposed, and a preliminary design has been suggested to mitigate this unstable condition caused by climate warming effects over a 20-year design period. The method described in this paper is a sound approach for assessing the stability of road embankments using a geothermal model, and it proposes a viable design process for adaptation solutions to preserve permafrost underneath road embankments in Canada's North.

A full-scale study was conducted at Universit & eacute; Laval's indoor accelerated pavement facility in order to document the mechanical behaviour of a flexible pavement structure affected by an idealised transverse crack. The constructed pavement structure was subjected to different temperature conditions and loading repetitions using the Accelerated Transportation Loading System (ATLaS). Various sensors, in particular strain gauges, were embedded at precise positions around the idealised crack. The paper presents the methodology undertaken, and a comparison of longitudinal strains measured in the reference area to measurements around the crack. The study demonstrated that a transverse crack fundamentally alters longitudinal strain and bottom-up fatigue damage patterns compared to uncracked sections, leading to accentuated bottom-up cracking at a distance from the crack.

Permafrost degradation occurs underneath the side slope due to snow accumulation, which prevents heat from being extracted from the ground in winter. This paper presents the in situ snow dynamics and thermal behavior of an airstrip in an area of continuous permafrost, in Nunavik, Quebec, Canada. The dynamic change of snow thickness around the embankment toe was measured in the field during 2014-2015. Thermistor strings were installed under the side slope and around the toe of the embankment. An empirical relationship between snowpack thickness and the freezing n-factor was proposed. The ground temperature data collected were used to calibrate a thermal conduction model, which was then used to develop the design chart for gentle slopes. The design chart was further validated using data from another experimental site at Tasiujaq airstrip in Nunavik, Canada. This work enhances the design capacity of gentle slopes to stabilize thaw-sensitive permafrost beneath the embankment shoulder.

Since the 1990s, an obvious increase in mean annual air temperature has been recorded in Nunavik, Quebec. This has resulted in the degradation of permafrost, threatening the stability of airstrip infrastructure managed by Transport Quebec. The air convection embankment (ACE) on side slopes with additional crushed rocks on the natural ground provides one option to preserve permafrost around the toe of embankments where permafrost degradation usually first occurs. To test the combined thermal effectiveness, this protection technique was used at the Puvirnituq airstrip in Nunavik, Quebec, in the summer of 2009. Thermistor strings were installed under the ACE layer to monitor the annual variation of ground temperatures near the toe of the embankment. The measured data indicate cooling trends at the ACE layer/natural ground interface, and the rise of the permafrost ceiling was observed. A numerical model based on site-specific conditions was developed to reproduce subsurface thermal regime and evaluate long-term climate warming effects. The model was calibrated using ground temperature measurements collected between 2010 and 2015. Numerical results indicate that the new type of ACE produces thermal cooling benefits as well as shifts the worst degradation location away from the embankment toe. This study provides a new design option for the ACEs to preserve warming airstrip infrastructures, and this design should be considered for other airstrip infrastructures in Nunavik, Quebec.

Pavement design in cold regions is challenging due to the difficult conditions of soils, humidity, and temperatures. Insulation layers have been identified as a suitable solution for these conditions. Due to their unique engineering properties, foam glass aggregates (FGAs) are a promising material for use as an insulating granular layer in pavement design. However, understanding their mechanical performance is critical for predicting long-term layer and pavement behavior. In this laboratory study, an empirical transfer function was developed using an environmental and heavy vehicle simulator and an experimental pavement built in an indoor test pit. The study aimed to determine the allowable number of load repetitions for an FGAs insulation layer and to develop an empirical transfer function that can be used as part of a mechanistic-empirical pavement design procedure. This article proposes a linear relationship between permanent deformation, the number of load cycles, and the equivalency factor between the effect of resilient strain, or vertical stress, and allowable damage. The proposed empirical transfer functions allow defining an allowable number of load repetitions for a characteristic resilient strain or vertical stress and an allowable damage. The allowable damage can be modulated with respect to road classification, and a damage value of 0% to FGAs layer can be considered as a safety factor. The findings of this study provide valuable insights into the use of FGAs as an insulating granular layer in pavement design in cold regions.

Transportation infrastructure is of vital importance to the local communities in Nunavik, Quebec, Canada. Permafrost degradation results in infrastructure failures and affects social and economic development. The case study of airstrip embankment at Salluit was selected to help improve the understanding of ground thermal conditions in Nunavik. This paper presents the analysis of thermal data collected at the Salluit airstrip and one two-dimensional geothermal model developed to reproduce the subsurface thermal regime under the centerline of airstrip embankment. The measured embankment dimension and air temperature were used as the inputs to improve the model accuracy. Field measurement of ground temperatures for a two-year monitoring period from 2016 to 2018 was used to calibrate the model developed. This study provided valuable information to investigate the vulnerability of the airstrips using the simulation approach in response to climate warming effects in Nunavik.

Climate warming has affected the transportation infrastructure in Nunavik, Quebec, Canada. Heat drain is an innovative heat extraction technique using density-driven convection of the pore air in the geocomposite of the heat drain to cool the ground during winter. This paper examines the thermal conditions of the road embankment including a heat drain installed in the shoulder at Salluit, Nunavik, Quebec, Canada. Following the installation of the heat drain, a decrease of the soil temperatures was observed. A 2-D finite element geothermal model was developed to reproduce the thermal regime underneath the heat drain, based on the site condition at Salluit. Field measurement of ground temperature for the four year monitoring period from 2012 to 2016, were used to calibrate the model. After the calibration, the long-term climate warming effects on the ground thermal regime was investigated using the model developed.

There are 14 northern communities in Nunavik, the Arctic region of Quebec province, Canada. Transportation infrastructure plays a vital role in the social and economic development of these localities. The thawing of permafrost compromises the stability of northern transportation infrastructure. Harsh Arctic climate conditions limit the installation of effective monitoring systems to assess infrastructure stability. In Akulivik, the access road connects the Akulivik airport and the village of Akulivik. There is no monitoring to observe the thermal condition of the permafrost foundation of the access road, hindering the capacity to perform preventive maintenance activities, especially in the context of observed climate warming in Nunavik. This paper describes a project aiming at the assessment of the stability of the access road using a new approach and proposes adaptation solutions to stabilize the road, based on design tools recently developed. Particular attention was paid to the foundation soil under the side slope where relatively rapid permafrost degradation was occurring due to accumulated snow. The results indicate a positive thermal gradient of 0.29 degrees C/m under the side slope and a near-zero thermal gradient under the centerline. Projected climate warming was also considered to further investigate the thermal condition, providing a safety margin for the design of promising adaptation solutions. These results assist government agencies in evaluating the thermal conditions of underlying permafrost and deploying potential adaptation solutions in Akulivik.

This manuscript focuses on the use of foam glass aggregates (FGAs) as insulator to protect pavements against frost action. The ultimate objective of the paper was to develop design tools for the thermal design of pavements insulated with FGAs. A mathematical model was outlined to describe the complex thermal behavior of FGAs and calculate temperature levels within a domain representing a pavement insulated with FGAs. The formulation is based on the one-dimensional heat equation which was discretized with a forward finite-difference technique and subsequently coded in Fortran90. This code was executed to successfully replicate temperature measurements collected within an experimental pavement insulated with FGAs, enabling the validation of the model. The model was then re-executed to perform three different sensitivity analyses and investigate the effects of the pavement geometry, layers humidity, and FGAs’ effective particle size on the maximal frost front penetration. Compared to a pavement without insulation, utilizing FGAs reduced the maximal frost front depth. The sensitivity analyses were summarized in design charts to guide the utilization of FGAs for the thermal design of pavements. The code utilized to generate these charts is freely available on GitHub.

Observed and projected climate warming affects the thermal stability of airstrip foundation in Nunavik, Canada. Intensive maintenance is needed to keep a reasonable service level. The paper focus on a case study of permafrost beneath the airstrip embankment at Tasiujaq, Nunavik. Field measurements of 6 years thermal data have been used to calibrate a 2D finite element model developed to reproduce the thermal condition of airstrip foundation and simulate soil temperatures. The model developed was well calibrated to the measured temperature data, supporting the reasonable accuracy of developed model. Specific interest was paid to the side slope, where rapid permafrost degradation was expected. One adaptation solution was also proposed, based on documented thermal stabilization approach.

The permanent deformation of granular materials is an important indicator in making decisions associated with the traffic of superheavy vehicles on pavements. The PBD model, a recently developed mechanistic-empirical model, analyzes the effect of superheavy load vehicles using the plastic strain rate as an indicator. The plastic strain rates of materials subjected to repeated cyclic stresses are defined by two states: (1) the post-compaction phase and (2) the shakedown state, with a probable range of permanent deformation being defined from each of these states. This paper explores the limits of applicability of the PBD model at different times in the stress history of granular materials. An accelerated pavement test with typical pavement structures from Quebec (Canada) is used as a reference. The changes in the plastic strain rate to variables related to the stress history in the granular material were studied, and a probabilistic relationship is proposed to improve the analytical predictions of the PBD model.

Abrupt thaw of ice-rich permafrost in the Arctic Foothills yielded to the formation of hillslope erosional features. In the infrastructure corridor, we observed thermal erosion and thaw slumping that self-healed near an embankment. To advance our understanding of processes between infrastructure and hillslope erosional features (INF-HEF), we combined climate and remote sensing analyses to field investigations to assess an INF-HEF system and validate our findings in a broader area along the infrastructure corridor. We identified that thaw consolidation along an embankment formed a thermokarst ditch that was ubiquitous in the broader study area, and which was extensively affected by shrubification and supported other positive feedback (e.g., snow accumulation, water impoundment, and weakened vegetation mat). The thermokarst ditch facilitated channelization of cross-drainage water, thus increasing the terrain vulnerability to thermal erosion that evolved into thaw slumping after heavy rainfalls. The terrain resilience to thaw slumping benefited from the type of ground ice and topography prevailing at our site. The lateral discontinuity of massive ice in an ice-wedge polygonal system (i.e., interchange soil and massive ice) compounded to a low-slope gradient with topographic obstacles (e.g., baydzherakhs) decreased slumping activity and supported self-stabilization.