Voids and discontinuities within hardened cementitious mixtures are often the result of entrapped or entrained atmospheric gases. These internal features can range in size from microscopic to macroscopic and are typically spherical or irregular in shape. For example, improper consolidation during the pouring process may leave larger spaces within the material.
The presence of these features can significantly impact the structural integrity, durability, and aesthetic appearance of the hardened material. Historically, understanding and controlling their formation has been a key focus in concrete technology to enhance performance and longevity in various construction applications. Their presence influences resistance to freeze-thaw cycles and chemical attack, as well as compressive strength and permeability.
