What material is added to mortar to enhance its bonding abilities?

Adding hydrated lime to mortar is beneficial for enhancing its bonding abilities. Hydrated lime improves the workability and adhesion of the mortar mix, creating a more robust bond between bricks or blocks. It also allows for better plasticity and flexibility, contributing to the overall durability of the mortar once it cures.

In addition, hydrated lime can aid in controlling the setting time and is known for its capacity to improve the resistance to cracking and shrinkage. This versatility makes it a popular choice among masons aiming for high-performance mortar.

Other options may seem plausible but do not contribute to enhancing bonding in the same way. For example, adding more sand can alter the proportions of the mix, potentially weakening it by making it too dry or reducing the cement paste that is available to surround the aggregates. Similarly, adding water can improve the consistency of the mortar but can also dilute the bond strength if used excessively. Adding more cement can increase strength but does not necessarily enhance bonding the way hydrated lime does.