To improve the air content in mortar, which agents may be added?

The addition of air-entraining agents is a common practice to enhance the air content in mortar. These agents create tiny air bubbles within the mix, which serves several beneficial purposes. The presence of these microscopic air pockets improves the workability of the mortar, helps to reduce water demand, and mitigates the risk of damage from freeze-thaw cycles. This is particularly important in climates where moisture can freeze and expand, potentially leading to cracking or spalling in masonry structures.

Air-entraining agents improve the durability and longevity of mortar by allowing for better expansion and contraction without causing damage. Unlike other agents mentioned, such as water-repellent or corrosive agents, which serve different functions, the specific role of air-entraining agents in increasing air content is directly aligned with the objectives of creating a resilient mortar mix.