What indicates that a surface finishing technique has been performed to close off pores in the concrete?

The indication that a surface finishing technique has effectively closed off pores in the concrete is represented by troweling. This process involves using a trowel to smooth and finish the surface of the concrete after it has been placed. Troweling compacts the top layer and helps to fill in voids and pores, resulting in a denser, less permeable surface. This is crucial for enhancing the durability and water resistance of the concrete, ultimately contributing to its overall longevity and performance.

The other options do not focus on the closure of pores in the concrete. Dusting typically refers to a surface defect caused by improper curing or finishing, where a fine powder forms on the surface. Crazing describes fine cracks that appear on the surface of the concrete due to shrinkage, which does not relate to pore closure and could even indicate problems with the finish. Edging involves rounding off the corners of the concrete at joints, which enhances appearance and safety but does not contribute to closing pores in the surface.