What Is The Difference Between Creep And Shrinkage?
What Is The Difference Between Creep And Shrinkage?
What is Creeping in Concrete?
Creep in concrete refers to the deformation of concrete under a sustained load over time. It is a phenomenon that occurs in all concrete structures, although the amount of creep can vary depending on the type of concrete and the conditions to which it is subjected.
Creep is the slow, gradual increase in strain of a structural element that has been subjected to a specific load over a period of time. When concrete is subjected to compression, it experiences elastic strain. If the load is sustained, the concrete will undergo creep strain over time.
The concrete’s strength and mixture, the type of aggregate used, the curing process, the relative humidity, and the duration of the sustained load all influence the amount of creep strain that occurs.
What is Shrinkage in Concrete?
Shrinkage in concrete refers to the contraction of concrete as it cures and hardens over time. All concrete structures experience some level of shrinkage as they age, although the amount of shrinkage can vary depending on the type of concrete and the conditions to which it is subjected.
As concrete dries and hardens, it undergoes a contraction process called shrinkage. This is caused by the evaporation of moisture from the concrete. The amount of shrinkage increases over time. The type and amount of aggregate in the concrete significantly impact shrinkage.
Larger aggregate leads to lower shrinkage, while a higher aggregate content results in a lower water-cement ratio and reduced workability. Shrinkage may also be increased by a decrease in ambient humidity.
What Is The Difference Between Creep And Shrinkage?
When a concrete structure is subjected to compressive loading, it will immediately deform, a phenomenon known as instantaneous strain. However, if the load is maintained for a long period of time, the concrete will undergo additional deformation, even without any increase in the load, a process called creep.
On the other hand, drying shrinkage, or simply shrinkage, is the reduction in volume of hardened concrete due to loss of moisture through evaporation. Both creep and shrinkage are caused by the loss of adsorbed moisture from the hydrated cement paste, but shrinkage is due to differences in the relative humidity of the concrete and its environment, while creep is caused by sustained applied stress.
The strain-time curves for both phenomena are similar, and the factors that affect creep also affect shrinkage, such as a higher cement content, higher water content, lower aggregate content, low relative humidity, high temperature, and a small thickness of the member.
However, shrinkage is not dependent on loading conditions and can be recovered to a greater extent, while creep cannot.
Shrinkage can also cause the development of tensile stresses in concrete when it is restrained in structural members, leading to cracking. Both shrinkage and creep can be mitigated by minimizing the water content in the concrete mix.
