What is it in a concrete structure, what is a cold joint?
The cold joint is undesirable discontinuity between the layers of concrete that occurs when one layer of concrete allows to solidify before the rest of the concrete is poured into what is to be the only solid. The discontinuity occurs between the layers due to the inability of freshly poured, wet concrete to project and weigh the hardened concrete correctly. Such discontinuity is often the result of logistics problems, such as a supplier's work plan or an unexpected lack of material. At the less serious end of the spectrum, the cold joint can lead to visually unattractive discontinuity - called the cold joint lines - which is visible on the surface as soon as the concrete solidifies. This kind of aesthetic defect can be simply hidden rather than repaired.
A more serious problem associated with the cold joint is the possibility of getting wet by the concrete section. If the water settles in a cold joint, this can lead to concrete degradation under certain environmental conditions. For example, as the water expands when it freezes and thenDownloads when it melts, water caught in a cold joint can cause cracking or erosion of the material. Moisture can also damage other things outside the concrete mass if it is able to leak all the way.
In addition, the cold joint is a compromised force area. The concrete is remarkable with its high strength under compression, but is much weaker under tension. The cool joint is even weaker under tension and is prone to cutting at discontinuity.
Whenever possible, in the concrete structure, cold joints should avoid the completion of the entire pouring for a given section in one session. This allows the whole section to harden in continuous, solid. If it is not possible that a few steps can be taken to alleviate more serious problems.
Specialized joint seal with waterproof joint can be applied to the joint to be waterproof to protect against potentially damagingMoisture. Special surface preparation may be applied before applying a fresh concrete layer. This strengthens the binding between the two layers. Another way to increase the strength of the cold joint is to insert a reinforcement molding or reinforcement into the first layer before pouring another layer. It is better to help combine them together and increase the joint strength of the joint. Sometimes it is also possible to find a weakened joint in an area that is not critical for supporting heavy loads.