Bleeding during concreting of a newly placed slab connected to an existing slab will cause which surface condition?

• A. The surface will become rough and pitted
• B. The surface will develop cracks
• C. The surface will cure evenly with no cracks
• D. The surface will shift and misalign at the joint

Answer: (B)

Bleeding is the upward movement of water to the surface during fresh concrete placement. When a new slab is placed against an existing one, the joint is restrained, and the surface layer that forms from bleeding becomes relatively weak because of the laitance and the extra water in the top zone. As the concrete continues to cure and shrink, the restrained surface cannot accommodate the movement as well as the interior, so tensile stresses develop at the joint. This combination of a weak surface layer and restrained shrinkage commonly leads to cracking along the surface at the joint, rather than a uniformly smooth or evenly cured surface.