Characteristics of Concrete

These are the characteristics of the concrete.


Elasticity

The elasticity of concrete is relatively constant at low stress levels but it starts to decrease at the higher stress levels as matrix cracking occurs. Which means when it exerts the compression limit, it will crack usually in a vertical direction. . 

Craking

As it matures, it shrinks. Shrinkage and tension will cause all the concrete structures to crack up to some extent. Creep will occurs on the concrete that has been subjected to a long-duration of forces. The density of concrete varies by the components of it, but it is around 2,400 kg/m³.  Thus, concrete would always fail from tensile stresses. Therefore, concrete elements are always subjected to tensile stresses that must be reinforced with materials that are strong in tension to increase the tensile strength of it. 

There are two types of cracking which are tension cracking and shrinkage cracking.

Tension Cracking. Concrete maybe put into tension by applied loads. Applied load will put one surface into compression and the opposite surface into tension due to induced bending. Size and length of cracks depend on the magnitude of the bending.

Shrinkage Cracking occurs when concrete undergo volumetric changes (shrinkage) as a results of either drying, autogenous shrinkage or thermal effects. When the tensile strength is exceeded, crack will occurs. Amount of shrinkage that occurs, amount of restraint present and amount and spacing of reinforcement provided will influence the number and width of shrinkage cracks that occurs. These minor cracks have no real structural impact on the concrete member.

Creep

Creep is the permanent movement or deformation of a material in order to relieve stresses within the material. A long-duration forces which is applied to the concrete will cause the concrete to be  prone to creep. Short-duration forces do not cause creep. Creep can reduce the amount of cracking that occurs in a concrete structure or element.