What is the purpose of a bond breaker when forming joints or patches?

• A. To prevent adhesion between concrete surface and forms or new concrete.
• B. To accelerate curing.
• C. To color the surface.
• D. To seal joints after placement.

Answer: (A)

Bond breaker is a release agent used when forming joints or patches to keep fresh concrete from sticking to forms or to the existing surface. This lets the joint or patch separate cleanly, ensures easy form removal, and allows proper movement at the joint without tearing or pulling on the concrete. It creates a defined, unbonded interface so the joint can function properly and be sealed later if needed.

It doesn’t speed up curing, color the surface, or seal the joint after placement. Those functions are handled by curing methods, pigments, and joint sealants, respectively.