Question

Shrinkage of concrete depends upon the:
A.Relative humidity of the atmosphere and passage of time
B.The moisture in the surrounding
C.Applied stress
D.Raining factor

Answer 1

Hint: Shrinkage or drying shrinkage is defined as the contracting of the hardened concrete mixture which is caused due to the loss of capillary water. Drying shrinkage depends on many factors, these factors depend on the properties of different components of the components.

Complete answer:
The question asks what does the shrinkage of concrete depend on but for knowing that we first need to understand what exactly shrinkage is.
This shrinkage is also called drying shrinkage. As the name only suggests what happens with the concrete is that it loses water in the capillaries. The shrinkage brings a lot of changes in the concrete. The shrinkage causes the increase in the tensile strength. Now as the tensile strength increases it can cause abnormalities like cracking of the concrete or maybe internal wrapping and other conditions.
Concrete shrinkage occurs mostly due to the evaporation of the icing capillary water. Rest of the drawbacks are dependent upon the physical structure of the component used for the concrete.
Now as we know there is a loss of water from the concrete which causes changes in the concrete’s physical properties. Now this loss of water happens because there is a change in pressure outside and inside the concrete. When there is a humid surrounding, it is easier for water to evaporate and as the time passes the drying shrinkage increases.
Relative humidity of the atmosphere and passage of time are the factors on which the shrinkage of concrete depends on.

Note:
Different compositions and fineness of cements have variable effects on the shrinkage of cement paste. Difference in shrinkage is reduced significantly due to the adjustment of the amount of gypsum added to the different cement compositions.