During construction, when a new slab bonds to an existing slab and bleeding occurs, what surface condition is anticipated?

• A. The surface will remain perfectly sealed
• B. The surface will show no cracking
• C. The surface will develop cracks
• D. The surface will cure too quickly

Answer: (C)

Bleeding brings water to the surface, which can dilute the surface paste and form a weaker, laitance layer. When the new slab is bonded to an existing one, the joint is restrained from shrinking freely. As the concrete hardens, the combination of water being pushed to the surface and the restraint from the old slab creates tensile stresses in the top layer. Those stresses commonly show up as surface cracks. So, the surface is expected to crack.

The other outcomes don’t align with this situation: the surface won’t stay perfectly sealed in the presence of bleed water and laitance, there’s typically some cracking rather than none, and curing rate isn’t inherently dictated by this bonded-bleeding condition to the extent described.