Harm of foam:

Foam in cement mortar can reduce the strength of the mortar, reduce its water-resistance, and increase its permeability. This can lead to structural damage over time due to water infiltration, which can cause cracking and spalling of the mortar. Foam also reduces the bond between the cement and aggregate, resulting in a weaker mortar. In addition, foam can trap air bubbles in the mortar, which can reduce its durability and increase its susceptibility to freeze-thaw damage.

Good advantage of antifoams and defoamers in cement mortar?

Antifoam can be used in cement mortar to reduce the foaming that occurs during mixing. It works by breaking down the surface tension of the foam bubbles, allowing them to collapse and disperse. This reduces the amount of air entrained in the mortar, resulting in a stronger and more durable mix. Antifoam can be added directly to the mix or sprayed onto the surface of the cement before mixing.

Which defoamer is used for cement mortar?

Generally, silicone-based defoamers are be used in cement mortar. Silicone-based defoamers are designed to reduce the surface tension of the liquid, which prevents the formation of foam. They are also non-toxic and safe for use in cement mortar.