What does the term "bleeding" refer to in fresh concrete?

The term "bleeding" in the context of fresh concrete specifically refers to the phenomenon where water rises to the surface due to the settlement of solid particles within the mix. As the heavier particles, such as sand and gravel, settle down under the influence of gravity, excess water, which is lighter, is forced upwards. This can create a pool of water on the surface of the freshly poured concrete.

Bleeding is an important factor to consider during the finishing process because it can affect the overall strength and quality of the concrete surface. If the surface is not carefully finished when bleeding occurs, it may lead to surface weaknesses or interfere with bonding for any applied finishes. Proper understanding and management of bleeding are essential for achieving desired surface characteristics and performance in concrete flatwork.