A cold joint is a joint or discontinuity resulting from a delay in placement of sufficient duration to preclude intermingling and bonding of the material, or where mortar or plaster rejoin or meet. 5-22 Topics in Concrete: Joints, Movement;. But do you know what concrete cold joints are? 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. The delayed placement prevents full integration and knitting between the concrete batches and might. A contraction joint is formed, sawed, or tooled groove in a concrete structure to create a weakened plane to regulate the location of cracking resulting from the dimensional change of different parts of the structure. In this comprehensive guide, we'll delve into all aspects of cold joints in concrete. We'll explore its main causes and share some innovative strategies to tackle the problem.