Deformation in concrete due to sustained loading is known as creep. Creep refers to the gradual increase in deformation or strain of a material under a constant load over time. In the case of concrete, this deformation occurs as a result of the ongoing hydration process and the rearrangement of the cement particles.

Creep is an essential consideration in the design and analysis of concrete structures, especially those subjected to long-term or sustained loads. It can have significant implications for the overall performance and durability of the structure.

Below, we will discuss the factors contributing to creep in concrete and its effects.

b Factors Contributing to Creep in Concrete:
1. Hydration: Creep in concrete is primarily influenced by the ongoing hydration process. As concrete cures, the hydration of cement particles leads to the formation of calcium silicate hydrates (C-S-H), which contributes to the strength and stiffness of the material. However, this ongoing hydration also causes a gradual increase in deformation over time.

2. Aggregate Properties: The properties of the aggregates used in concrete, such as size, shape, and surface texture, can affect the creep behavior. Aggregates with a higher porosity or higher water absorption capacity may lead to increased creep.

3. Moisture Content: The moisture content in the concrete plays a crucial role in creep. Higher moisture content can result in increased creep, as the water facilitates the movement and rearrangement of cement particles.

4. Temperature: Temperature also influences the creep behavior of concrete. Higher temperatures generally accelerate the hydration process and increase creep deformation.

c Effects of Creep in Concrete:
1. Long-term Deformation: Creep results in long-term deformation or strain in concrete structures, which can lead to excessive deflections and deformations. This can affect the serviceability and functionality of the structure.

2. Cracking: The gradual deformation caused by creep can induce tensile stresses in the concrete, leading to cracking. These cracks can compromise the structural integrity and durability of the concrete.

3. Loss of Prestress: In pre-stressed concrete structures, creep can cause a loss of prestress over time. This can lead to a reduction in the load-carrying capacity of the structure.

4. Redistribution of Loads: Creep can result in the redistribution of loads within a structure, as the deformed regions may experience higher stresses. This can lead to uneven loading and potential structural failures.

In conclusion, creep in concrete refers to the deformation that occurs under sustained loading over time due to the ongoing hydration process and rearrangement of cement particles. It is influenced by factors such as hydration, aggregate properties, moisture content, and temperature. Understanding and accounting for creep is essential in the design and analysis of concrete structures to ensure their long-term performance and durability.