When critical runways or access roads fail in sub-zero conditions, military operations face serious constraints—fighter jets stay grounded, supply convoys get rerouted, and repairs must wait until spring thaw allows safe paving. For installations worldwide, winter construction shutdowns don't just delay projects; they can compromise mission readiness when it matters most
Runways, roads, parking lots, and storage areas. The U.S. military uses a lot of asphalt. However, paving is difficult in cold temperatures, which poses a significant problem for the many DoD installations located in colder climates across the globe.
As temperatures drop, the asphalt binder's viscosity rises and the mat cools rapidly—especially over a cold base or with wind—shrinking the compaction window. Rollers can't achieve target density before the mix "locks up," leading to higher permeability, weak joints, and cracking. Current specifications set 50 degrees Fahrenheit as the minimum temperature for most surface paving to avoid these failures.
But what if asphalt could be compacted in freezing conditions without compromising quality?
A research project led by the U.S. Army Engineer and Research Development Center's Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, New Hampshire, aims to do just that.
“The issue in cold-weather paving isn’t just the outside air”, said Dr. Mohamed Elshaer, a CRREL research civil engineer and the project’s leader. It’s a combination of three key temperatures: the ground surface, the temperature of the asphalt mix at delivery and the ambient air.
To accurately represent field conditions, the team developed a controlled lab protocol that accounts for all three and mimics real-world compaction scenarios. The team is testing three plant-produced, production mixes from New England—sampled during routine operations to reflect real-world materials and practices. Each, with different material types and sources, represents different traffic classes and applications, modified with commercially available warm-mix chemical additives.
"We used a chemical additive to lower asphalt binder viscosity and therefore the effective compaction temperature, keeping the mix workable longer in the cold while still meeting density and performance targets," Elshaer explained.
Using a field-replicated cold-paving protocol that mimics real-world paving and rolling operations, the team has compacted two-inch surface course lifts—a particularly challenging thickness for cold-weather operations due to rapid heat loss —across a full temperature spectrum, from typical summer paving conditions down to 50 degrees Fahrenheit and subfreezing temperatures as low as 20 degrees Fahrenheit, with the 20 degrees Fahrenheit testing specifically for urgent operations.
By controlling ambient air, base, and mix/mat temperatures, simulating typical field delays, and tracking how quickly asphalt cools, the team generates cooling curves for each mix type using embedded temperature sensors and infrared surface readings that pinpoint the lowest practical window to achieve proper compaction.
“Today’s paving operations are often halted below 50 degrees Fahrenheit, depending on lift thickness, wind, and base temperature, but this study aims to demonstrate that certain asphalt types can still achieve proper compaction under colder conditions,” said Elshaer.
The findings so far are encouraging. All three asphalt mixtures successfully met standard compaction requirements when tested at cold temperatures. One mixture required increased compaction effort—specifically, additional roller passes—at the lowest temperatures, but still achieved target specifications.
Performance testing on asphalt cores taken after compaction shows strong resistance to cracking, the dominant distress in cold-region pavements.
"Achieving these results with two-inch lifts is particularly significant," Elshaer noted. "Thin lifts cool rapidly and typically represent the most challenging conditions for cold-weather compaction, so this success demonstrates real-world applicability.”
"So far, all cold-temperature slabs have met target quality standards," Elshaer noted. "The goal isn't to override specifications, but to provide evidence that can inform future standards when conditions and materials permit."
While lab results demonstrate that cold-weather compaction is achievable under controlled conditions, the next step is conducting field trials to validate performance under actual operational conditions with real equipment, weather variables and time constraints.
“These trials would evaluate performance in DoD environments—from remote airfields to high-traffic roads—and inform guidance for safe, lower-temperature paving,” said Elshaer.
According to Elshaer, 94 percent of U.S. paved roads are surfaced with asphalt, so these findings represent a potential game-changer: a practical path to extend paving seasons, reduce schedule risk and costs, and strengthen infrastructure resilience and mission readiness across DoD operations in cold regions. The work also has national relevance for state and local agencies operating in similar climates, with asphalt contractors already expressing strong interest in extended paving seasons.
For military operations in harsh climates with short construction windows, the benefits extend beyond cost considerations. Operational readiness is often paramount on military projects, where non-functional runways or roads directly impact mission capability. Remote locations and heightened security concerns make construction delays particularly costly and operationally damaging.
While existing specifications often limit paving operations below about 50 degrees Fahrenheit to prevent quality issues, Elshaer says the current thresholds were based on older practices and limited data. This study introduces a new level of control and precision—utilizing temperature-controlled testing, embedded sensors, and modern asphalt technologies—to determine whether quality compaction can still be achieved successfully at lower temperatures.
This effort directly supports the DoD’s resilient infrastructure goals by helping ensure that airfields and roadways can be built or repaired even during shortened construction seasons.
“The findings will guide cold-weather paving practices, reduce premature pavement failures, and ultimately support extended paving windows, stronger infrastructure resilience, and improved mission readiness in extreme environments,” said Elshaer.
A version of the article first appeared in the Nov/Dec issue of The Military Engineer magazine. Republished with permission.