What is the purpose of curing compounds and how are they applied?

• A. To color the surface
• B. To accelerate curing by chemical reaction
• C. To reduce evaporation and keep the surface moist; apply after initial set, typically by spraying or brushing a film-forming coating
• D. To seal the slab after full cure

Answer: (C)

Maintaining moisture in the concrete surface during early curing is essential for proper hydration of the cement. A curing compound forms a film on the surface that slows evaporation, keeping the surface moist so hydration can continue. It’s applied after the concrete has gained enough strength to resist finishing damage (after initial set) and is usually sprayed or brushed on as a uniform film. This approach helps reduce plastic shrinkage and cracking and improves final strength and durability. It isn’t used to color the surface, accelerate curing chemically, or seal the slab after full cure.