During concreting of a newly added slab joined to an old slab, what is the surface expectation if bleeding occurs?

• A. The surface will form a tight seal with the formwork
• B. The surface will bleed excessively and warp
• C. The surface will develop cracks
• D. The surface will gain unexpected strength

Answer: (C)

Bleeding brings excess water to the surface, leaving a weak laitance layer on top. That thin, soft layer can’t carry the tensile stresses as the concrete finishes hardening and undergoes shrinkage. As a result, surface cracks are the likely outcome, especially where a new slab is joined to an old one and finishing occurs while bleed water is present. A tight seal with formwork, warping from bleed, or a gain in strength wouldn’t occur; instead, the surface is prone to cracking. To prevent this, finish after bleeding stops and ensure proper curing.