What modification is made to concrete to increase its resistance to freeze - thaw damage?

Increase Freeze and Thaw damage resistance:

The continuous action of freezing and thawing will affect the concrete with greater effect. It will cause cracks, and failures in the concrete structures. As per the ACI recommendations following modifications can be done to improve the freeze and thaw resistance.

• Proper percentage of accurate sized and spaced air bubbles into the concrete.
• Providing minimum compressive strength.
• Concrete should be designed with high density and low permeability.
• Concrete should be properly cured and dehydrated.
• Mixing of fly ash with the concrete helps to increase the resistant capacity.
• Fly ash will occupy minute voids and give more dense concrete with less absorbing quality.
• The spherical shape of the fly ash particles helps to reduce the bleeding channels and also controls the void spaces.