Insufficient vibration or consolidation during concrete placement can lead to voids or excessive air in interface between the two concrete sections (creating weakened bonding results and leading to cold joint formation). A cold joint occurs when a new batch of concrete is poured against a layer that has already started to set (harden). Instead of the two layers fusing into a monolithic mass, they create a distinct, visible line with a very weak bond. ### **⚠️ Why do they happen? (Causes)** * **Unplanned Delays:**. While RCC is generally a sound material, one potential defect that can seriously impact the performance of an RCC project is cold joints in concrete. These can sometimes be undetectable, but they are a danger to the stability of any concrete project. This guide will discuss the definition of cold. A cold joint in concrete is an area or surface with a structural discontinuity caused by the delayed concrete pouring between two layers of concrete.
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