What is Outgassing in Concrete? How to Prevent Outgassing in Concrete?

Concrete outgassing is defined as the phenomenon of air expansion and its releasing through the concrete pores. This is a process that occurs when the concrete seeks equilibrium with its surrounding. This happens by releasing air and water vapor when the temperature increase and by absorbing water vapor and air when the temperature decreases.

Outgassing in Concrete
Image Credits: The Euclid Chemical Company

What Causes Outgassing in Concrete

1. Concrete with high air content
2. Coatings that are 100 percent solids or high solid coatings 
3. New concrete tries to attempt or expel the original entrained air
4. An unprepared surface
5. Concrete at a higher temperature
6. Rising temperature
7. Fluctuations of barometric or atmospheric pressure
8. Concrete with contaminants with varying pH content
9. A thick layer of exothermic coatings

How to Prevent Outgassing in Concrete?

1. Use of penetrating primers
2. Breathable high-density mortar or polymer slurry coats
3. Avoiding direct sun exposure to the concrete
4. Awareness of changing temperature

Also Read:

1. Blisters in Concrete - Identification, and Causes
2. Bugholes in Concrete - Causes, and Prevention