Journal of Cold Regions Engineering

Temperature is the most influential climatic variable for flexible pavement design using a mechanistic-empirical approach. While the effect of climatic variables on pavement designs has been previously investigated, few studies went further to seek potential temperature indices to correlate with distress predictions of flexible pavement. This study aims to explore the correlations between distress predictions and various potential temperature indices. The distresses investigated include total rutting, asphalt concrete rutting, thermal cracking, top-down cracking, bottom-up cracking, and the international roughness index (IRI). The temperature types in this study primarily include the pavement surface temperature and the air temperature. The temperature indices investigated include the annual average temperature, average temperatures in hot months and cold months, and standard deviation of annual temperature. Pavement distresses were obtained using the climatic information collected from the 39 weather stations throughout the state of Michigan. The pavement surface temperature was obtained by the enhanced integrated climate model (EICM). The correlation coefficient (R-values) between each distress prediction and each temperature index was obtained to determine the strength of correlation. Several valuable findings were obtained, including that the surface temperature in hot months exhibited very strong positive correlations with asphalt concrete (AC) rutting and total rutting. Annual average temperature showed correlations with thermal cracking as strong as the average temperature in cold months. The average annual temperature showed moderate correlations with bottom-up cracking but very weak correlations with top-down cracking. In addition, the optimum combination of the high temperature index and the low temperature index can have a strong correlation with predicted IRI. The paper also shows an example of climate zone creation based on the temperature indices, which were selected from the correlation analysis. The findings in this study can help further understand the effects of temperature indices on pavement designs. They are also beneficial for the parameter selection for climate zone creation, especially for pavement designs in the future.

Electroosmosis (EO) is considered a promising technique for reducing water content in soft soils. In this study, a multiscale experiment was conducted to investigate the effectiveness of EO in controlling the water content of in-service pavement subgrade soil. First, the effect of EO dewatering was investigated through a laboratory-scale experiment considering three types of soils and two levels of electric voltages. Then a field-scale pavement subgrade was constructed to evaluate the engineering feasibility of EO. Conventional natural drainage was also investigated for the purpose of comparing the efficiency of EO dewatering. Results from the laboratory-scale experiments indicate that natural drainage is only useful for sand and silt, but EO dewatering works well for clay because the average reduction of the water content of the two clays is 3.47 and 3.78% with a voltage of $24\mathrm{V}/\mathrm{m}$, and the dewatering performance is improved with an increase in voltage. The validity of EO dewatering in reducing the water content of clay ground is confirmed through the field-scale experiment.

Frost heave is the primary cause of frost damage in cold regions. For frost-susceptible soils, water migration induced by a temperature gradient is a key factor in determining the frost heave of the soils with a water supply during the freezing process. This study looked at the effect of temperature gradients on frost heave through a series of one-directional freezing experiments for a saturated silty clay with a water supply under a variety of temperature gradients. The results indicate that the deformation and water intake of the saturated silty clay with water supply increase with the temperature gradient. The water intake of the soil begins when the freezing front drops to a critical advance rate, which is linearly related to the temperature gradient. However, even if the freezing front is stationary (advance rate of zero), a small temperature gradient is still needed to induce water intake by the soil and to cause a sizeable frost heave. The temperature gradient and the freezing rate can be regarded as two macroindexes that indicate the frost heave of soils with a water supply during the freezing process.

Biodiesel is increasingly used in transportation and heating as an alternative to diesel fuel, furthering sustainability by reducing fossil fuel use and posing lower risks when spilled. The bioremediation of soil contaminated with a 20% fish biodiesel blend or heating diesel (HD) was studied in laboratory microcosms. Fresh fuel and artificially weathered fuel were compared by placing activated carbon (AC) in the microcosms to remove volatile fuel fractions, accelerating hydrocarbon weathering. After a brief lag phase, during which all microcosms behaved similarly, microbial respiration increased exponentially. In general, biodiesel blend was biodegraded faster than HD and high degradation rates were sustained substantially longer for biodiesel blend than for HD. Cumulative mineralization was considerably higher for biodiesel blend than for HD fuel. The weathering induced by activated carbon suppressed mineralization rates for the first three weeks, resulting in lower cumulative mineralization and nitrogen use. As calculated from nitrogen consumption, about 10% of the carbon from hydrocarbons was incorporated into biomass. After four weeks, approximately only half of the fuel hydrocarbons remained in the soil. Overall, accelerated fuel weathering, caused by AC addition, especially when frequently changed, resulted in decreased fuel mineralization, decreased nitrogen use, and lower respiration values during the exponential phase compared with controls without AC.

This paper aims to present the results of an experimental investigation related to the unconsolidated undrained triaxial compression behavior of fine-grained soil as a function of freeze-thaw cycles, and fly ash–lignin fiber volume fractions. All the measurements were carried out for three selected fly ash fractions (0, 4, and 8%), and five selected lignin fiber fractions (0, 0.25, 0.5, 0.75, and 1%). The specimens were exposed to from 0 to 15 freeze-thaw cycles before testing. It has been observed that for the studied soil, the compression strength of unreinforced soil decreased with an increment the number of freeze-thaw cycles. Moreover, the fly ash–lignin fiber–reinforced soil specimens showed greater effect on compression strength after the 15th freeze-thaw cycle. The greatest amount of strength reduction was obtained on the maximum blend ratios of the lignin fiber. Also, the reduction trend of cohesion was declined for the reinforced soil and the resilient modulus of all soil specimens reduced after the 15th freeze-thaw cycle.

Frost action is one of the most important factors contributing to pavement damage in cold regions. Frost action causes a gain regarding the bearing capacity of flexible pavements due to the viscoelastic response of asphalt concrete and to the freezing of pore water in granular materials and soils. Pavement strengthening with frost penetration has led some transportation agencies to allow winter weight premiums for the trucking industry, but rational and technical decision criterion for the increase of the axle load limit are limited. The objective of this project was thus to document the mechanical behavior of flexible pavements as a function of frost penetration and axle load. The Laval University full-scale heavy-vehicle simulator was used to monitor the response of two flexible pavements built in a $24\text{-}{\mathrm{m}}^3$ indoor laboratory pit over a silty sand and low-plasticity clay subgrade soils, respectively. The pavements were instrumented to monitor temperature profiles, surface deflection, stress, strain, and moisture in each layer. The simulator was used to freeze the pavement downward using a $-10°\mathrm{C}$ surface temperature, and to periodically load the pavement surface using a standard dual-wheel set (half-axle) loaded in the range of 4,500–6,250 kg. The results collected allowed documenting response modification of different pavement structures changes as a function of frost penetration and temperature. It was also shown that the pavement response variation with respect to axle load variation becomes nonsignificant when 600-mm frost depth is reached, and that the associated pavement damage becomes negligible when frost depth reaches 400–500 mm.

This paper presents the relationships between various winter weather conditions and the total expenditure on purchasing and applying snow and ice control materials and operation costs (labor and equipment) using historical data in Texas, U.S. Work includes developing a statistical model to estimate the normalized total expenditures on snow and ice control based on the amount of snowfall in three different climate regions in Texas. The model reliably predicts total expenditures on snow and ice control based on the amount of snowfall in the current and preceding months, and the model performs better for colder regions than for warmer ones. Coefficients reflecting the level of sensitivity of expenditures to snowfall amount exhibit considerable disparity among six Texas Department of Transportation (TxDOT) districts. The findings and the proposed methodology from this study could be applied to formulate more effective snow and ice control plans at the district level in Texas or other geographic areas with distinct and similar microclimates and annual average snowfall.

Mechanical property variations of base course materials caused by freezing and thawing must be considered when designing subgrades in regions with seasonal freezing and thawing. In this study, static triaxial tests were performed to investigate the properties of reconstructed base course materials with optimum water contents subjected to freeze-thaw cycles; reconstructed base course materials are extensively used for China’s high-speed railway. The material strength significantly decreased with increasing freeze-thaw cycles, particularly during the first cycle. The results show that the minimum strength was frequently achieved after the specimen had been exposed to six freeze-thaw cycles.

This paper addresses the following questions: Does ice jam thickness vary transversely (across channel) in bends? If so, what processes cause such variation? The questions pertain to wide-jams in bends where no flow separation occurs at the bend lee, and were addressed using a large, bend flume with polypropylene beads as model ice floes. The primary finding is that, other than in narrow regions along the flume’s outer bank, no consistent pronounced transverse variation of jam thickness occurred. However, beads drifting at relatively low velocity and low discharge around the bend produced a jam marginally thicker in a narrow region along the flume’s outer bank. A much greater discharge of beads spread more uniformly over the approach channel produced no consistent transverse variation of jam thickness. Collapse-thickening produced transverse uniformity of jam thickness.