Which phenomenon describes water rising to the surface of freshly placed concrete?

The phenomenon that describes water rising to the surface of freshly placed concrete is known as bleeding. This occurs during the curing process when a portion of the mixing water rises to the surface as the concrete begins to set. Bleeding happens due to the gravitational forces acting on the water and the settlement of solid particles within the concrete mix. As the heavier aggregates settle, the water, which is lighter, moves upwards, leading to a temporary accumulation of water on the surface. This phenomenon is important to recognize because excessive bleeding can affect the durability and finish of the concrete, potentially leading to issues such as weak surface layers or the need for additional finishing work. Understanding bleeding helps concrete finishers manage the finishing process effectively, ensuring that the surface remains suitable for subsequent treatments.