What is the appropriate technique for finishing a concrete slab after setting?

The appropriate technique for finishing a concrete slab after setting is to trowel the surface after the initial set to create a smooth finish. This process is crucial because once the concrete has set sufficiently, it is workable enough to be shaped and smoothed without damaging the surface. A trowel is used to further compact and polish the surface, giving it a professional appearance and enhancing durability.

Achieving a smooth finish is particularly important in many applications where aesthetics, ease of cleaning, and the overall quality of the concrete work are vital. A troweled surface is less prone to cracking and other damage, resulting in a finished product that can withstand various environmental factors.

Other alternatives, such as brushing the surface or leaving it rough, would not provide the desired finish if a smooth surface is required. Rough surfaces may promote bonding in some contexts, but it's generally not the optimal method for finished concrete slabs. Applying a sealant immediately after pouring is also not advisable because the concrete must cure properly to achieve maximum strength and prevent issues with adhesion or moisture entrapment.