What Does Moving Crack Mean?
A moving crack is a crack in a material or a concrete structure that moves in one direction at a uniform speed and is generated by the application of a large amount of stress on the material, usually more than the designed stress holding capacity of the material. These cracks are generally one millimeter wide and penetrate the full depth of the material. Moving cracks often have rough and wide edges as a result of freeze-thaw cycles and edge impacts.
Corrosionpedia Explains Moving Crack
Cracks occur in metals and often in concrete. There are two types of cracks that occur in materials and in concrete structures:
- Moving cracks
- Non-moving cracks
Moving cracks are thicker, wider, deeper and continuous in one direction, whereas non-moving cracks are much thinner, shallower, non-continuous and move in random directions. There are many reasons why cracks form, including:
- Thermal and drying shrinkage of the concrete
- Defects in the materials used
- Material flexure
- Natural calamities such as earthquakes and wind storms
When moving cracks form in a concrete structure, the reinforced steel structure is exposed to the environment, thus further weakening the structure from the inside due to rusting and corrosion of the steel structure. Proper actions must be taken to avoid structure failure. Some suitable measures:
- Treat the cracks with low viscous epoxy
- Apply methyl methacrylate or high molecular weight methacrylate
However, moving cracks are difficult to repair and the success depends on the total movement of the cracks. Such cracks should be repaired in accordance with American Concrete International (ACI) standards.