What is necking of concrete?

Necking of concrete refers to the localized reduction in cross-sectional area that occurs in a concrete specimen under tensile stress. This phenomenon typically happens before failure and is characterized by a noticeable narrowing at a specific point, indicating that the material is reaching its ultimate tensile strength. Necking can lead to cracking and eventual failure of the concrete, making it an important consideration in structural design and analysis. Understanding this behavior helps in predicting the performance and durability of concrete structures under load.