How Temperature & Moisture Cause Asphalt Cracks
Asphalt pavement is engineered for strength and durability, but environmental stressors like temperature and moisture are constant threats to its integrity.
The changing seasons expose asphalt to expansion and contraction cycles, as well as freezing and thawing, each contributing to the development of cracks. These small openings can worsen quickly when moisture seeps in and undergoes temperature shifts, turning a minor flaw into a major repair issue.
For property owners in colder climates, these seasonal fluctuations are more than just a nuisance—they're a significant factor in long-term pavement performance and maintenance costs.
Understanding how temperature and moisture interact with asphalt is key to preventing premature deterioration. This article explores five critical subtopics. Each section provides expert-level detail and advice, helping readers grasp the science behind the surface while reinforcing the importance of proactive care.
For additional insights into asphalt repair, continue reading below as we uncover the root causes and contributing factors of asphalt cracking.
Thermal Expansion & Contraction: Why Asphalt Reacts to Seasonal Changes
Asphalt is a viscoelastic material, meaning its properties change in response to temperature variations.
During hot summer months, the pavement absorbs heat and expands. In colder months, it contracts as temperatures drop.
This repetitive expansion and contraction lead to thermal fatigue and place stress on the asphalt’s structure.
Over time, these stresses can cause small fractures to appear, particularly in high-traffic areas or where the base layer was not properly compacted. The cracks that emerge from this process often follow linear patterns and are known as thermal cracks or transverse cracks.
How Aggregate Plays a Role
Because asphalt is composed of aggregates bound together by bitumen, the differential movement between these materials under thermal cycling contributes to internal stress.
The rate of thermal expansion is affected by asphalt mix design, with softer binders generally being more susceptible.
In regions like Minnesota, where summer and winter temperatures can range over 100°F apart, the movement is significant enough to initiate early-stage cracking even within the first few years of installation.
When these minor cracks form, they open a pathway for water and debris infiltration, which can worsen the problem dramatically.
To prevent structural damage, asphalt repair strategies like crack sealing are commonly used to address the problem before it escalates. This is particularly relevant in climates with extreme seasonal variation, where proactive maintenance can delay major repairs.
Freeze-Thaw Dynamics: How Trapped Water Destroys Asphalt from Within
One of the most damaging processes to asphalt pavement is the freeze-thaw cycle. Water that enters existing cracks can remain trapped beneath the surface.
When temperatures drop below freezing, the water turns into ice, which expands approximately 9% in volume. This expansion exerts outward pressure on the surrounding asphalt, forcing the crack to widen and creating new fractures along weak points.
When temperatures rise and the ice melts, the water may penetrate deeper into the base layers, weakening the pavement structure further.
Repeated freeze-thaw cycles—common in northern states—can produce frost heaving, where sections of pavement are lifted as a result of ice formation beneath them.
Once the ice thaws, the surface settles unevenly, causing structural instability, potholes, and further cracking. These effects compound quickly during winter months when daily temperature fluctuations hover around the freezing point, allowing multiple freeze-thaw cycles within a 24-hour span.
Residential asphalt surfaces are especially vulnerable to this damage, making timely maintenance a priority for homeowners.
Many residential services include early crack detection and sealing, which helps to prevent water ingress and reduce the risk of severe structural failure caused by freezing conditions.
Sun Exposure & Oxidation: The Role of UV Rays in Crack Formation
Sunlight plays a significant role in the aging process of asphalt pavement. Ultraviolet (UV) radiation from the sun causes oxidation of the bitumen binder, which is responsible for holding the asphalt aggregate together.
Over time, this oxidation results in the binder becoming brittle and less elastic. As the flexibility of the pavement diminishes, it becomes more prone to cracking, particularly under mechanical stress like vehicle traffic or shifting subgrades.
Prolonged exposure to high temperatures from direct sunlight also contributes to surface softening during peak summer months.
This softening can lead to rutting and distortion, and when the softened material cools rapidly at night, it can contract unevenly and form cracks.
The combined effect of UV degradation and thermal cycling accelerates the formation of longitudinal and block cracks that reduce the overall lifespan of the surface.
While UV damage is less visually dramatic than freeze-thaw effects, it is a continuous process that can go unnoticed until structural issues become visible.
The absence of protective sealants or coatings exacerbates the rate of degradation, especially in open, unshaded areas. Strategic maintenance planning should include monitoring sun-exposed areas for early signs of embrittlement and surface cracking.
Humidity & Aging: Moisture’s Effect on Asphalt Longevity
High humidity levels introduce additional moisture into the asphalt system, both at the surface and within the underlying layers.
Although humidity alone does not cause visible damage as quickly as freeze-thaw conditions, it does promote long-term deterioration. Prolonged moisture exposure softens the bituminous binder, weakens the bond between binder and aggregate, and creates a more porous surface.
This compromises the pavement’s ability to resist traffic loads and environmental stressors.
In humid environments, the presence of surface moisture also interferes with proper compaction during installation or repair. If moisture becomes trapped within the layers during construction, it can lead to stripping, where the binder loses adhesion to the aggregate.
This undermines the pavement structure from within and results in early failure, even if the surface appears intact. Over time, minor flaws can evolve into extensive cracking and surface raveling.
Humidity also enhances the growth of mold, algae, and organic debris within surface pores, which further degrade the surface through biological processes and make it slippery or hazardous.
Regular inspections and proactive treatments are essential to mitigate the long-term impact of humid conditions, particularly in regions with consistent moisture exposure year-round.
Cold Climate Stress: How Harsh Winters in Minnesota Affect Asphalt Pavement Life
Extreme winters in Minnesota subject asphalt pavement to some of the most punishing conditions in the country.
Rapid temperature fluctuations, heavy snowfall, and continuous freeze-thaw cycles create a relentless assault on pavement integrity.
As snow melts and refreezes, water infiltrates the asphalt and base layers, causing them to expand and contract with each cycle. The accumulation of this movement over the winter months causes progressive fatigue, resulting in cracked networks, potholes, and surface delamination.
The use of snow removal equipment and deicing chemicals adds further stress. Snow plows can cause mechanical abrasions that break the asphalt surface, while chemical agents seep into minor cracks and accelerate deterioration.
These conditions make winter maintenance not only a necessity but a protective measure that extends pavement lifespan by preventing damage from reaching critical levels.
Asphalt surfaces that lack protective measures like sealcoating or timely crack sealing will degrade at a much faster rate in Minnesota’s subzero environment.
For these reasons, pavement design and repair strategies in cold climates must be tailored for durability and resilience.
Expert Asphalt recommends region-specific approaches to installation and maintenance that are suited for the extreme conditions seen in the Twin Cities and across Minnesota. For comprehensive care and expert advice, visit Expert Asphalt.
Protecting Your Asphalt Investment with Expert Asphalt
Expert Asphalt specializes in a full range of services tailored to these specific challenges, including professional crack sealing, sealcoating, asphalt replacement, and surface maintenance.
Our team is well-versed in the science behind asphalt deterioration and uses that knowledge to provide long-lasting solutions.
Whether you’re managing residential driveways or commercial parking lots, their region-specific expertise and proactive care make a significant difference in durability and performance.
If your asphalt surface is showing signs of wear due to temperature shifts, moisture, or harsh winter conditions, contact Expert Asphalt today. You can reach us at 952-657-1181 for a personalized consultation.
To learn more or schedule a site inspection, visit our contact page for free estimates and take the first step in safeguarding your pavement investment.