Shrinkage in Concrete

Shrinkage in Concrete

Shrinkage in Concrete

Definition:

Shrinkage is the contraction of concrete due to the loss of moisture during setting and hardening.

Types of Shrinkage:

1. Plastic Shrinkage:

   • Occurs soon after placing the concrete in formwork.
   • Caused by rapid evaporation of water or absorption by aggregates.
   • Cracks develop at the surface or subgrade due to restraining effects.
   • Prevention: Using powdered admixtures and expanding cement.

2. Drying Shrinkage:

   • A long-term and irreversible process.
   • Primarily due to the loss of water from gel pores.
   • More pronounced in finer gel structures.
   • Shrinkage decreases with:
     • Increase in member size.
     • Higher relative humidity.