The Shrinkage cracks in concrete are a common phenomenon which has been frequently observed. The shrinkage cracks in concrete basically appear due to a change in the concrete’s moisture. The materials which are used for building are very much porous as far as their structure is concerned. The building materials expand whenever they absorb moisture. Once these materials get dried, they shrink. The shrinkage cracks in concrete are a process which is irreversible.
Shrinkage Cracks in Concrete: The Common Types
There are basically two types of shrinkage cracks in concrete. The types have been briefly discussed in the headings below
Initial Shrinkage
The building materials which are based on cement or lime etc. usually get affected with initial shrinkage cracks in concrete. The initial shrinkage basically occurs during the structural member’s construction. The cracks appear due to the moisture’s drying. In case the moisture is maintained inside the concrete, then the process can be reversed as well. However once the concrete gets dried then under such a scenario the process cannot be reversed at all.
Factors
The factors on which initial shrinkage depends are as follows
- Content of the cement
- Content of water
- Aggregate grading and quality
- The process of curing
- Aggregate fines and their presence
- Cement’s chemical composition
- Fresh concrete’s temperature
Plastic Shrinkage
After the placement of concrete, the plastic shrinkage in concrete occurs. After the occurrence of shrinkage in concrete the water in concrete also rises as far as the surface is concerned. This entire process is technically referred to as the bleeding of concrete. Until the settling of water in the concrete, the bleeding process continues.
Factors
The plastic shrinkage in concrete depends upon the following factors
- Ambient air humidity
- Concrete temperature
- Heat exposure
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