What does "efflorescence" refer to in concrete?

Efflorescence refers specifically to the formation of white crystalline deposits on the surface of concrete, which occurs when water-soluble salts are brought to the surface of the concrete as water evaporates. As moisture moves through the concrete, it can dissolve salts present in the mix or from the surrounding environment. When the water evaporates, these salts crystallize, creating the characteristic white deposits.

This phenomenon is important for concrete finishers to understand, as it can affect the aesthetic quality of concrete surfaces and may indicate potential moisture issues within the material. Recognizing and addressing efflorescence can help in maintaining the integrity and appearance of the concrete, and potential remedies include sealing the surface or improving drainage to reduce moisture content.

The other options point to different aspects of concrete behavior but do not accurately describe efflorescence. Understanding efflorescence is crucial for ensuring the durability and quality of concrete finishes.