Journal of Cold Regions Engineering

Biocovers are a promising technology for mitigating methane (${\mathrm{CH}}_4$) emission from landfills. The geotechnical performance of the biocover material is one of the design criteria of biocovers. However, current understanding of the geotechnical behavior of biocovers under freeze-thaw conditions is limited. In the present paper, the effects of freeze-thaw cycles (FTCs) on the geotechnical (thermal, hydraulic, and mechanical) properties of compost-based biocovers are investigated by column experiments. In the experiments, three columns are developed, prepared, and treated by a period of methane injection (0 FTCs) after 1 FTC and 2 FTCs in three respective stages. In addition, extensive laboratory testing is carried out on the biocover samples with regard to their thermal (thermal conductivity); hydraulic (hydraulic conductivity); and mechanical (compressibility and shear strength) and physical properties (e.g., grain size distribution, moisture content). The results show that the FTCs induced changes in a number of the geotechnical properties of the biocover. However, these changes are mostly located in the top layer of the biocover (0–15 cm). It was found that FTCs significantly increased the hydraulic conductivity of the top layer of the biocover, whereas they slightly decreased the thermal conductivity of this layer. As for mechanical and physical factors, the average grain size of the compost surface slightly decreased throughout the stages, while the friction angles of the bottom and middle layers of the compost-based biocover were not significantly affected. The results presented in this paper will contribute to better design of landfill biocovers in cold regions.

Thermal mass in building construction refers to a building material’s ability to absorb and release heat based on changing environmental conditions. In building design, materials with high thermal mass used in climates with a diurnal temperature swing around the interior set-point temperature have been shown to reduce the annual heating demand. However, few studies exist regarding the effects of thermal mass in cold climates. The purpose of this research is to determine the effect of high thermal mass on the annual heat demand and thermal comfort in a typical Alaskan residence using energy modeling software. The model simulations show that increased thermal mass can decrease the risk of summer overheating in Alaskan residences. They also show that increased thermal mass does not significantly decrease the annual heat load in residences located in cold climates. These results indicate that while increased thermal mass does have advantages in all climates, such as a decrease in summer overheating, it is not an effective strategy for decreasing annual heat demand in typical residential buildings in Alaska.

Roadway maintenance equipment in cold climates is exposed to high amounts of chloride-based deicers that are inherently corrosive. As such, various structural, hydraulic, and electrical components on maintenance equipment are vulnerable to the deleterious effects of chloride roadway deicers, and their premature deterioration can negatively affect the performance, reliability, and service life of the equipment fleet. This work aims to shed more light on this important asset management issue by providing an overview of corrosion-prone parts and current approaches available to proactively manage the risk of deicer corrosion to equipment assets, including design considerations, materials selection, and maintenance strategies. The information aims to enable equipment engineers and managers to gain a better understanding of this technical issue and make more informed decisions in corrosion risk management.

This study investigates the stiffness and tensile strength degradation behavior of asphalt concrete (AC) on long-term freeze-thaw (FT) conditioned samples in the laboratory. In the first step, beam samples ($363\times 63\times 50\mathrm{mm}$) are prepared in the laboratory using a kneading compactor and conditioned at different numbers of full-day FT cycles up to 150. The flexural stiffness of control and FT conditioned beam samples are determined using a beam fatigue test apparatus. In the second step, circular (100-mm diameter) samples of 50-mm thickness are prepared using a SuperPave gyratory compactor and conditioned in a FT chamber similar to the beam samples. The indirect tensile strength (ITS) of control and FT conditioned circular samples are determined by indirect tensile strength (IDT) tests at different temperatures. Results show that the flexural stiffness of the FT conditioned samples decreases with FT conditioning, whereas the ITS of AC does not change significantly with FT cycles. It is highly expected that the findings of this study will be useful to understanding the damage behavior of AC in cold regions.