What’s Happening in this Photo? Freeze-Thaw
This photo shows a reinforced concrete surface that is deteriorating from freeze-thaw conditions.
With civil and structural infrastructure, particularly reinforced concrete structures, a proper condition assessment is the best way to identify the root cause of deterioration.
Below is an explanation of freeze-thaw disintegration taken from Concrete Repair and Maintenance Illustrated, written by Peter Emmons, president and founder of Structural Technologies:
Freeze-thaw disintegration or deterioration takes place when the following conditions are present:
- Freezing and thawing temperature cycles within the concrete
- Porous concrete that absorbs water (water-filled pores and capillaries)
Freeze-thaw deterioration generally occurs on horizontal surfaces that are exposed to water, or on vertical surfaces that are at the water line in submerged portions of structures. The freezing water contained in the pore structure expands as it is converted into ice. The expansion causes localized tension forces that fracture the surrounding concrete matrix. The fracturing occurs in small pieces, working from the outer surfaces inward.
The rate of freeze-thaw deterioration is a function of the following:
- Increased porosity (increases rate)
- Increased moisture saturation (increases rate)
- Increased number of freeze-thaw cycles (increases rate)
- Air entrainment (reduces rate)
- Horizontal surfaces that trap standing water (increases rate)
- Aggregate with small capillary structure and high absorption (increases rate)
