Concrete is being placed in an area with recurrent freezing and thawing. Which admixture should be used?

When concrete is placed in an area that experiences recurrent freezing and thawing, it is crucial to ensure its durability and resistance to damage from repeated freeze-thaw cycles. The correct choice of admixture in this scenario is air-entraining agents.

Air-entraining admixtures work by creating microscopic air bubbles within the concrete mix. These tiny air pockets provide space for water to expand when it freezes, which helps to relieve internal pressure that could otherwise lead to cracking and spalling of the concrete as the water within it freezes and thaws. This characteristic is particularly important in cold climates, where the concrete is subjected to these challenging conditions.

Using air-entrained concrete significantly enhances its resistance to freeze-thaw deterioration, thereby extending its lifespan and maintaining its structural integrity. This practice is widely recommended and often required in areas exposed to harsh weather conditions to ensure that the concrete performs well over time. Other types of admixtures, such as accelerators or decelerators, do not specifically address the freeze-thaw vulnerability of concrete in the same way as air entrainment does.