What is the purpose of a bonding agent in concrete repair?

• A. To improve adhesion between old and new concrete.
• B. To accelerate curing
• C. To color the repair
• D. To reduce cost

Answer: (A)

Bonding agents provide a bridge between the existing concrete and the fresh repair material. They improve adhesion at the interface so the new patch acts as part of the same structural element, allowing better transfer of stresses and reducing the risk of delamination or cracking at the repair joint. For best results, prepare the old surface by removing laitance, cleaning, and roughening, then apply the bonding agent before placing the repair material. This purpose is different from curing accelerators, colorants, or cost reduction, which don’t directly enhance the bond between old and new concrete.