Types of Shrinkage cracks in concrete

The Shrinkagecracks in concrete are a common phenomenon which has been frequentlyobserved. 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 inConcrete: The Common Types
There are basically two types of shrinkage cracks inconcrete. 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 processcan 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 asfollows
-         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 inconcrete 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 followingfactors
-         Ambient air humidity
-         Concrete temperature
-         Heat exposure