Compressed Snow Blocks: Evaluating the Feasibility of Adapting Earth Block Technology for Cold Regions

Abstract

Snow construction plays a crucial role in military operations in cold regions, providing tactical fortifications, thermal insulation, and emergency infrastructure in environments where conventional building materials are scarce or require extensive infrastructure for support. Current snow construction methods, including manual piling and compaction, are labor-intensive and inconsistent, limiting their use in large-scale or time-sensitive operations. This study explores the feasibility of adapting a compressed earth block (CEB) machine to produce compressed snow blocks (CSBs) as modular, uniform building units for cold-region applications. Using an AECT Impact 2001A hydraulic press, naturally occurring snow was processed with a snowblower and compacted at maximum operating pressure (i.e., 20,684 kPa) to evaluate block formation, dimensional consistency, and density. The machine successfully produced relatively consistent CSBs, but the initial 3–4 blocks following block height adjustment were generally unsuccessful (e.g., incorrect block height or collapsed/broke) while the machine reached its steady state cyclic condition. These blocks were discarded and excluded from the dataset. The successful CSBs had mean block heights of 7.76 ± 0.56 cm and densities comparable to ice (i.e., 0.83 g/cm³). Variations in block height and mass may be attributed to manual snow loading and minor material impurities. While the dataset is limited, the results warrant further investigation into this technology, particularly regarding CSB strength (i.e., hardness and compressive strength) and performance under variable snow and environmental conditions. Mechanized snow compaction using existing CEB technology is technically feasible and capable of producing uniform, structurally stable CSBs but requires further investigation and modifications to reach its full potential. With design improvements such as automated snow feeding, cold-resistant components, and system winterization, this approach could enable scalable CSB production for rapid, on-site construction of snow-based structures in Arctic environments, supporting the military and civilian needs.

1. Introduction

As a naturally abundant material with high thermal insulation and load-bearing capacity, snow offers a unique construction medium in environments where conventional building resources are scarce or difficult to transport [1,2,3] (pp. 15–66; pp. 311–320). Indigenous peoples, notably the Inuit, have used snow to build semipermanent structures such as igloos for centuries, leveraging its compacted strength and insulating qualities [4] (pp. 328–338). More recently, architects and designers in countries like Norway, Finland, and Canada have explored snow and ice as eco-friendly construction materials for seasonal tourism infrastructure such as ice hotels, snow restaurants and bars, as well as emergency shelters [5]. This traditional knowledge has evolved into a growing field of research encompassing the strategic use of snow in military and scientific applications.

For military operations in Arctic and subarctic regions, snow fortifications offer significant logistical advantages. Research by the US Army Cold Regions Research and Engineering Laboratory (CRREL) has advanced our understanding of snow’s structural behavior under varying conditions, including blast resistance and dynamic loading [6,7]. These insights have informed the design of compacted snow runways, foundations, and protective berms [8] (pp. 1–11). Scientific research, particularly in the context of climate-resilient infrastructure, has focused on how snow and ice can be stabilized or enhanced using additives like biodegradable fibers to extend the life and safety of snow-based structures in changing weather conditions [6,9].

While snow fortification has traditionally relied on manual methods such as shoveling, piling, and compacting snow into forms or molds, these techniques are labor-intensive and can produce variable results depending on snow type, temperature, and operator experience [6]. In military or emergency scenarios where speed, uniformity, and structural reliability are critical, these current ad hoc methods of building snow walls, windbreaks, or shelters can pose limitations. A novel and promising approach involves the adaptation of compressed earth block (CEB) machines for use with snow. CEBs have a long-standing history as a sustainable building material across a range of climates and cultures. Originating from ancient earthen construction techniques (e.g., adobe) seen in regions such as Zimbabwe and Britain [10] (pp. 259–271), CEBs are made by mechanically compacting a mixture of soil, stabilizers, and sometimes cement into dense, modular units [11,12] (pp. 1–9; pp. 47–55). These blocks offer high thermal mass, fire resistance, and low embodied energy, making them attractive for both rural development and environmentally conscious urban projects [11] (pp. 1–9). Modern applications of CEBs span humanitarian housing initiatives, low-cost construction in developing nations, and innovative green architecture in urban settings [13,14].

Research studies and field experiments have long explored mechanized snow compaction methods, though to our knowledge, none have directly applied existing CEB press technology to snow. The potential exists to produce compressed snow blocks (CSBs) with consistent density, shape, and strength by adapting CEB machines for operation in subfreezing conditions and for the unique physical properties of snow. The present study investigates this feasibility using an unmodified CEB press as an initial step toward such adaptation. These blocks could serve as modular units for rapid, scalable snow construction in both military and civilian contexts. Depending on the machine’s rate of block production (e.g., 240–300 blocks per hour [12,15]), the application of CSBs over traditional shovel- or hand-packed snow could lead to faster assembly times and the potential for prefabrication. For example, CSBs could be stockpiled and transported short distances for use in building perimeter defenses, thermal shelters, or temporary infrastructure like storage igloos, bunkers, and explosive detonation structures [16]. Additionally, integrating water or slush into the compaction process could allow the blocks to partially freeze into ice upon setting, further enhancing structural integrity. This hybrid approach mirrors recent techniques in snow architecture where water is sprayed onto snow forms to increase hardness and longevity [6].

The objective of this study is to investigate the feasibility of using a CEB machine with snow to produce CSBs (i.e., modular and mechanically compacted snow units). Specifically, this study aims to answer two main questions: (1) can a CEB machine produce CSBs when snow is applied to the system, and (2) are the resulting blocks unform in size and density? If successful, CSBs could offer advantages in cold region construction and fortification, such as improved consistency, efficiency, durability, and scalability.

2. Materials and Methods

2.1. CEB Machine

To evaluate the viability of producing CSBs using existing CEB technology, this study utilized the Impact 2001A hydraulic press manufactured by Advanced Earthen Construction Technologies (AECT; San Antonio, TX, USA) (Figure 1). Originally designed for the compaction of soil-based materials, the Impact 2001A features a steel mold box and piston assembly capable of generating significant compressive force, making it a suitable candidate for initial trials with snow. We used an existing soil block compactor from the US Army Geotechnical and Structures Laboratory (GSL) to test and create methods specifically for applying this block machine in cold weather.

The Impact 2001A is a trailer-mounted automated machine that produces 30.48 × 15.24 cm sized CEBs at a rate of 300 blocks per hour, with an adjustable block height between 5.08 and 11.43 cm tall [15]. It operates using a diesel-powered engine, compressing manually loaded soil under up to 20,684 kPa of pressure to form durable blocks. The machine features an adjustable hydraulic ram, allowing users to control block thickness (i.e., block height) based on soil moisture, which influences final dimensions. With an automated pressing and ejection system, it continues production if soil is continuously supplied.

2.2. Snow Collection and Processing

A field trial was conducted at CRREL in Hanover, New Hampshire, following a 4-day period of sustained subfreezing temperatures after a snowstorm produced 13.97 cm of fresh snow. The four-day subfreezing period helped to ensure snow stability during handling and compression. The snow used was naturally occurring, sourced from undisturbed, previously accumulated material next to one of the CRREL buildings. Sample location as well as recent historical weather patterns affect snow characteristics such as quality, moisture content, and crystal structure [17]. The snow was collected approximately 15 m south of the nearest building. In February, the sun rises in the southeast and sets in the southwest, meaning the snow collection spot was not shaded by the building when the sun was out. Although temperatures remained below freezing, two of the four days were overcast/stormy while the other two were mostly sunny. Melting/refreezing cycles from sun during the day (as well as diurnal temperature fluctuations) can impact the moisture content and density of the snow cover [18]. While this study provides a valuable proof of concept for using CEB machines with snow, future work should include more detailed testing that incorporates quantitative measurements of a broader range of snow characteristics. Such data will help clarify how these properties influence the strength and density of snow when compacted into blocks.

A gas-powered snowblower (Honda HS828 Snowblower, Torrance, CA, USA) was employed to mechanically break down and disaggregate the snow particles. This improved the consistency and flowability of the snow prior to compaction (i.e., the ability of the snow to easily and evenly flow off the shovel into the hopper rather than in chunks) (Figure 2) [3] (pp. 311–320). Snow grains ranged from approximately 2–3.5 mm prior to processing with the snowblower. After processing, snow grains were 1 mm on average. This process helped create a more uniform particle size and moisture distribution, enhancing its workability during subsequent handling. This processing step produced a more homogeneous snow matrix with consistent grain size and moisture distribution, establishing uniform initial conditions for subsequent sintering during compaction and curing [6,7]. Using this processed, homogeneous snow as the source material for all test blocks helped minimize variability due to natural heterogeneity in the sampled snowpack, reducing the likelihood that block-to-block strength differences resulted from local variations in snow density or bonding. Following snow processing, the material was manually shoveled into the feed hopper of the Impact 2001A, where it was compacted into blocks using the machine’s standard operation cycle at the maximum operating pressure of 20,684 kPa (per recommendation by AECT). Given that the machine was not originally designed for low-temperature operations or for compressing fine, cold particulate matter like snow, special attention was paid to machine performance, material ejection, and any mechanical sticking or jamming during pressing cycles.

Unlike traditional applications of the CEB machine, no stabilizers, additives, or moisture controls were applied to the snow. The primary focus of this study was to assess the machine’s ability to produce structurally intact CSBs using processed naturally occurring snow. Because of equipment and time constraints due to weather and resulting snow availability, the only quantitative data collected from each block were the dimensions (length, width, and height), weight, and density (calculated as mass divided by volume). Long-term strength and durability were not assessed as part of this initial phase. The collected data and metrics served as the basis for evaluating consistency and comparing outputs and uniformity across multiple blocks. In addition, preliminary observations focused on identifying necessary modifications or operational adjustments that could improve block formation and reliability. This proof-of-concept study served as the foundation for assessing both the technical feasibility and the logistical practicality of using mechanized compaction to produce snow-based construction units in cold region environments.

2.3. CSB Production

A total of 25 CSBs were produced throughout the field test process. One of the main objectives of this test was to determine how the Impact 2001A may need to be adjusted for use with snow instead of soil with additives, specifically the block height adjuster (the block length and width are fixed) and pressure valve. Through this process, we observed that following initial startup and after making any adjustment to the block height during the operational cycle, the following 3–4 blocks produced were not the correct block height. This was a valuable observation to note for future testing that it takes 3–4 operational cycles to achieve the new block height set on the machine. This was also observed in a previous, unpublished study performed by the ERDC Geotechnical and Structures Laboratory (GSL) [19]. These blocks were thereby considered “unsuccessful” as they tended to be half of the intended block height or less and were set aside (Figure 3). After these first 3–4 unsuccessful blocks, the machine would return to a steady state cyclic mode wherein blocks of consistent height were produced. In addition, structural failures (e.g., block collapse or chipping) were observed upon ejection from the block machine, and these were also set aside. After learning these operational limitations of the machine and excluding any failed block and those produced immediately following system startup or block height adjustment, 8 “successful” blocks remained that were produced sequentially (Figure 4). These 8 were produced with a block height setting of 7.62 cm. Some variation in block height exists between them and can likely be attributed to the inconsistent rate at which snow was shoveled into the hopper. This could be avoided in future testing by having more people adding snow in an alternating pattern to avoid time gaps or potentially blowing snow directly into the hopper from a larger source pile. The key is to try to match the rate of the CEB machine’s operational cycle as closely as possible. CSB height was immediately measured with a tape measure and then weighed approximately 45 min after being ejected from the machine. To accommodate the large size of the CSBs and the lack of proximity to a power source, a basic body health scale (Health o meter, McCook, IL, USA) was used to weigh the blocks. The collected data were used to calculate the density (i.e., mass/volume) of each block, and to evaluate uniformity across blocks, offering insight into the variability and compactness achievable with mechanized snow compaction.

3. Results

3.1. Block Properties and Consistency

Preliminary observations indicate that the Impact 2001A is capable of producing dimensionally consistent CSBs after accounting for the first few cycles (i.e., 3–4 blocks) following start up and block height adjustment. The mean block height was 7.76 cm (±0.56 cm) and the actual block height for all 8 blocks was within 1 cm of the intended block height (i.e., block height set on the machine) (

Table 1. CSB height, mass, and calculated density. Block length and width are constant per machine design (i.e., 30.48 cm long and 15.24 cm wide).

Block ID	Block Height (cm)	Block Mass (g)	Block Density (g/cm3)
A	6.67	2721.55	0.88
B	7.62	3175.14	0.90
C	7.62	3175.14	0.90
D	7.62	3175.14	0.90
E	7.78	3628.74	1.00
F	7.94	3401.94	0.92
G	8.26	3401.94	0.89
H	8.57	3628.74	0.91

). Mean block mass was 3288.54 g (±296.95 g), with block mass generally increasing with block height except for Block E, which was nearest to the average block height, but had the greatest mass along with Block H. All eight of the measured CSBs had a density consistent with ice (i.e., density greater than or equal to 0.83 g/cm³) (Figure 5) [20].

3.2. Visual Characteristics

Slight variations and abnormalities (e.g., small corners or other spots missing snow) in blocks were noted, most likely due to uneven snow loading into the hopper and the presence of impurities in the snow (e.g., small amounts of soil or small gravel from the surrounding collection areas). The Impact 2001A machine was borrowed from another lab who used it for extensive soil testing (as that is the traditional material for CEBs). As a result, there was also residual soil and sediment in the machine despite cleaning prior to adding snow, making the CSBs produced with the machine to appear dirty or orange or brown in color.

4. Discussion

4.1. Sources of Block Variability and Potential Impacts

As described in Section 2.2, the processed snow was manually added to the hopper using a shovel. Unfortunately, there was no way to ensure a perfectly even distribution of the snow across the bottom opening of the hopper where the snow would fall into the compression chamber during the operational cycle. This likely affected uniformity in block mass and density, as well as the visual observations made regarding small impurities where snow was missing in block corners or other surface locations. Residual soil contamination also influenced appearance and could impact thermal behavior. Impurities lower the surface albedo, potentially accelerating melting, making this an important consideration for structures requiring longevity. For testing purposes, these impurities could cause minor discrepancies when testing strength or other mechanical properties. However, in potential field applications, this discoloration would have a lower albedo than pure white snow, meaning it will absorb more solar radiation [18]. This would cause warming of the blocks and lead to melting, which could be detrimental to infrastructure constructed using CSBs. Depending on environmental context, discoloration could either hinder camouflage or improve it by blending with surrounding materials (e.g., pure white snowy backdrop vs. surrounding impurities from heavy trafficking) [16].

4.2. Implications of Density for Strength

The measured densities indicate that applying the maximum available pressure of the machine (i.e., 20,684 kPa) may not be necessary to achieve reasonably strong CSBs depending on the intended use. Prior studies have demonstrated sufficient strength for aircraft operations and ballistic protection at densities between 0.58 and 0.75 g/cm³ [6,7,21]. For example, one study demonstrated that a compacted snow runway test section with a density of 0.60 g/cm³ was sufficient to support the load of a C-130 aircraft [21] (pp. 231–247). An ERDC technical report demonstrated successful C-17 aircraft operations after constructing the Phoenix Runway in Antarctica that had an average density of about 0.75 g/cm³ at a depth of approximately 150–500 mm [7]. Alternatively, snow manually compacted into gabions at an average density of approximately 0.58 g/cm³ was successfully able to stop a range of ammunition showing its potential for ballistic protection in cold regions [6]. While snow density can provide a rough idea of potential snow strength, it is not a direct indicator of mechanical behavior (e.g., strength). Denser snow may suggest a more compact structure, but strength is influenced by additional factors such as grain type, temperature history, bonding between layers, and moisture content [22]. Previous CRREL studies have similarly shown that although density correlates with compressive and flexural strength, substantial variability arises from microstructural differences and snow metamorphism [23,24]. Therefore, assumptions about snow stability or load-bearing capacity should not be based on density alone. Further testing is needed to refine this potential technology for snow and cold region applications, such as block strength through penetration and compression testing, evaluating the effects of additives, and examining the impact of curing time.

4.3. Design Optimization and Future Development

Qualitatively, the proof-of-concept test revealed several areas for potential development and optimization that could improve this CEB technology for application with snow in cold regions, specifically to enhance efficiency, block consistency, and field usability. First, the hopper system could be redesigned to include an auger-fed or conveyor-driven snow intake, enabling continuous and even distribution of snow into the compression chamber, eliminating the inconsistency caused by manual shoveling. The chamber size should also be adjustable or enlarged to accommodate the formation of larger CSBs suitable for faster construction of snow shelters or defensive structures. Additionally, the frame and mechanical components should be winterized with cold-resistant materials and lubricants to ensure operation in subzero temperatures. During this field test, we observed a large amount of moisture dripping from the block mold down onto the mechanical components of the machine. This indicates a temperature increase in the snow because of the applied pressure, which is good for sintering purposes and therefore CSB strength (although strength was not measured in this study). While the current machine does have waterproof protection around the wiring directly under the mold, other components do not, and while this protects from moisture it does not protect from cold. Lastly, portability enhancements (e.g., collapsible components, large tires, trackpads) would improve deployment in rugged, snow-covered terrain (e.g., snow collection and compression equipment [25]). These changes would optimize the machine for rapid, reliable CSB production in remote and harsh extreme cold military environments. Per discussion with the AECT manufacturer [26], it may be possible to modify parameters of the block machine such as the block size, maximum applied pressure, size of the equipment itself, and how it is mounted (e.g., trailer mounted vs. stand-alone). According to AECT, we could also reposition and add enhanced waterproofing methods to the electrical components to protect from increased moisture conditions. Another possible modification having high importance in extreme cold regions would be changes to the motor including a cold weather start and the ability to support the flashpoint of JP8 fuel [26]. Overall, the findings of this proof-of-concept study support the technical feasibility of adapting CEB equipment for snow-based construction in remote or cold environments. However, further development is needed to improve repeatability and ensure consistent block integrity under varying snow conditions. Additional work should also include investigating potential chemical and biological additives (e.g., cellulose and Pseudomonas syringae) aimed at either increasing block strength or decreasing the required cure time to achieve said strength [2,27,28,29] (pp. 376–391; pp. 371–383; pp. 456–459).

5. Conclusions

This study aimed to evaluate the feasibility of putting snow in a traditional CEB machine to produce CSBs for construction and fortification applications in cold environments. The primary objective was to determine whether processed snow could be compacted into structurally sound, uniform blocks using a machine designed for compacting earth materials with stabilizers and additives. The results demonstrate that, after initial adjustment and stabilization (i.e., reaching a steady state cycle), the CEB machine was capable of producing CSBs with relatively uniform dimensions and satisfactory structural integrity using processed snow. Minor variations in block height and mass were observed, likely resulting from uneven snow loading and natural impurities in the snow, but overall consistency suggests that the method has potential for scalable, modular snow construction applications. While the data from this study are limited and indicate only relatively consistent block dimensions, the findings are sufficiently promising to justify further investigation of the performance and reliability of CEB machines in producing CSBs under varied snow (e.g., processed vs. unprocessed/natural, varying moisture content) and environmental conditions. These initial findings (and future studies) are particularly significant for military and logistical operations in cold regions, where the need for rapid, efficient construction is crucial. CSBs could potentially offer advantages over traditional snow fortification methods, such as enhanced load-bearing capacity, faster assembly times, and reduced labor requirements. The ability to produce uniform, durable blocks on-site would streamline the construction of temporary infrastructure, such as protective berms, shelters, and storage units, all critical to military operations in remote or hostile Arctic environments. While this study provides promising results, several factors need further investigation and development. This includes the effect of varying snow types/properties and environmental conditions on block quality (e.g., consistent block height, structural integrity, and impurities), block strength (e.g., hardness and compressive strength), as well as the scalability of the process. Future research should also explore the practical challenges and opportunities associated with using CSBs in large-scale military fortifications and rapid-response infrastructure development, such as modifications to the machine for use in extreme cold conditions. The successful production of CSBs opens exciting possibilities for military logistics in cold regions, providing a potentially game-changing method for constructing durable, transportable snow structures. Further exploration of this technique could enhance the speed, efficiency, and reliability of construction operations in challenging environments.