Joints in Concrete Construction:

When the large concrete members such as factory floors, long columns, residential floors, workshop floors, road pavements, air-field pavements and etc. are constructed, it is not advisable and practicable to place the concrete continuously within one stretch. A joint is left among subsequent concreting stretches and it is known as construction joint. Concrete might undergo expansion and contraction because of moisture movement, thermal changes, drying shrinkage and because of structural reasons. Thus to make up for the impending expansion or contraction of concrete a proper provision is made in the form of a joint. Such joints are known as contraction or expansion joints.

The concrete joints could be categorized as follows:

(a) Construction joints,

(b) Expansion joints, and

(c) Contraction joints.