Creep and shrinkage of concrete and relaxation of steel
The modulus of elasticity of concrete increases with its age. A stress applied on concrete produces instantaneous strain; if the stress is sustained the strain will progressively increase with time due to creep. Thus, the magni¬ tude of the instantaneous strain and creep depends upon the age of concrete at loading and the length of the period after loading. Other parameters affecting the magnitude of creep as well as shrinkage are related to the quality of concrete and the environment in which it is kept. Creep and shrinkage are also affected by the shape of the concrete member considered.