Which additive is used to enhance mortar bonding between masonry units?

Which additive is used to enhance mortar bonding between masonry units?

• A. Portland cement
• B. Hydrated lime
• C. Sand
• D. Water

Answer: (B)

Hydrated lime is used to enhance mortar bonding between masonry units due to its unique properties that contribute to improved workability and adhesion. When mixed into mortar, hydrated lime enhances plasticity, making the mortar easier to spread and manipulate during construction. This increased plasticity helps the mortar to better fill joints and adhere to the surfaces of masonry units, which optimizes the bond strength. Furthermore, hydrated lime can improve the durability and flexibility of the mortar, making it more resistant to cracking and allowing for a better long-term performance. Its ability to react with carbon dioxide in the atmosphere aids in the carbonation process, which can further strengthen the bond as time progresses. In contrast, while Portland cement is an essential component of many masonry mixes and contributes to strength, it does not specifically enhance bonding in the same way that hydrated lime does. Sand provides bulk and stability to the mortar mix but does not enhance adhesion. Water is necessary for hydration and curing, but by itself, it does not contribute to the bonding properties of the mortar. Thus, hydrated lime stands out as the most effective additive for this purpose in masonry applications.

Hydrated lime is used to enhance mortar bonding between masonry units due to its unique properties that contribute to improved workability and adhesion. When mixed into mortar, hydrated lime enhances plasticity, making the mortar easier to spread and manipulate during construction. This increased plasticity helps the mortar to better fill joints and adhere to the surfaces of masonry units, which optimizes the bond strength.

Furthermore, hydrated lime can improve the durability and flexibility of the mortar, making it more resistant to cracking and allowing for a better long-term performance. Its ability to react with carbon dioxide in the atmosphere aids in the carbonation process, which can further strengthen the bond as time progresses.

In contrast, while Portland cement is an essential component of many masonry mixes and contributes to strength, it does not specifically enhance bonding in the same way that hydrated lime does. Sand provides bulk and stability to the mortar mix but does not enhance adhesion. Water is necessary for hydration and curing, but by itself, it does not contribute to the bonding properties of the mortar. Thus, hydrated lime stands out as the most effective additive for this purpose in masonry applications.