Definition of Freeze-Thaw Cycle
A
freeze-thaw cycle is the recurrent
pattern of
water freezing and subsequently
melting. Integral to the
process of weathering that disintegrates rocks and other
surface materials on
Earth, freeze-thaw cycles are most prominent in temperate climates where
temperature variations exceed and fall below water's freezing
point (0°C or 32°F).
How Freeze-Thaw Cycle Works
In the freeze-thaw cycle, water first permeates cracks or pores in rocks, soil, or other materials. Following a drop in
temperature to
freezing point, this infiltrated water becomes ice and its
volume increases by about 9%. This volumetric
expansion exerts substantial
pressure on the encasing
material. With a temperature increase causing the ice to melt, the pressure dissipates. Repetition of the freezing, expanding, melting, and pressure release sequence can eventually lead to material disintegration.
Impacts of Freeze-Thaw Cycle
Freeze-thaw cycles wield considerable influence on both
natural environments and man-made
structures. In natural settings, they drive
physical weathering processes that contribute to rockfalls, landslides, and the
formation of specific landforms, including scree slopes - accumulations of loose rocky debris on a
gradient.
Within built environments, freeze-thaw cycles can inflict significant
damage on buildings and
infrastructure, culminating in road potholes, fractures in concrete structures, and compromised
building foundations. To mitigate such damage in freeze-thaw susceptible areas, construction methods may need to incorporate specific protective measures.
The freeze-thaw cycle also functions as a critical regulator in climate and
ecosystem dynamics. It modulates the
global carbon cycle by impacting the
speed of organic matter decomposition and
nutrient release within soils. In colder climates, freeze-thaw cycles can instigate "
frost heaving," a process where soil
moisture freezing causes
ground elevation and influences
plant life. The cycle also shapes the habitats and behaviors of numerous
cold-climate
organisms, necessitating their
adaptation to shifting
conditions.
Updated: Jun 5, 2023
Published by:
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