What is a common consequence of finishing a concrete slab too soon after placement?

What is a common consequence of finishing a concrete slab too soon after placement?

• A. Dusting and Crazing
• B. Curing faster
• C. Hardening more evenly
• D. Less surface texture

Answer: (A)

Finishing a concrete slab too soon after placement creates a weak, delicate surface layer. When the surface is still plastic and bleed water is present, troweling or floating pushes moisture and fines to the top, forming a thin laitance layer. This paste-rich surface is easy to dust off, producing the dusty top you can wipe away, and as moisture continues to evaporate, tiny cracks can appear in the top few millimeters—crazing. Together, dusting and crazing are classic signs that the surface was finished before it had stiffened and before proper curing could establish a strong, durable finish. Waiting for the surface to set, allowing bleed water to dissipate, and using appropriate curing practices helps prevent these issues.

Finishing a concrete slab too soon after placement creates a weak, delicate surface layer. When the surface is still plastic and bleed water is present, troweling or floating pushes moisture and fines to the top, forming a thin laitance layer. This paste-rich surface is easy to dust off, producing the dusty top you can wipe away, and as moisture continues to evaporate, tiny cracks can appear in the top few millimeters—crazing. Together, dusting and crazing are classic signs that the surface was finished before it had stiffened and before proper curing could establish a strong, durable finish. Waiting for the surface to set, allowing bleed water to dissipate, and using appropriate curing practices helps prevent these issues.