When a new slab is added or joined to an existing slab, and the new work bleeds during concreting, what will happen to the surface?

• A. The surface will develop cracks
• B. The surface will become glossy and smooth
• C. The surface will cure with a uniform finish
• D. The surface will lift at the joint

Answer: (A)

Bleeding brings excess water to the surface and carries cement fines up with it, forming a weak laitance layer. When a new slab is joined to an existing one, this surface weakness is especially prone to cracking because the joint imposes restraint and tensile stresses as the concrete hardens and shrinks. The top layer can’t resist these stresses well, so cracks develop along the surface.

This wouldn’t typically produce a glossy, smooth finish, nor a uniformly cured surface, and lifting at the joint isn’t the most likely outcome in this bleeding scenario.