Reason to soak the bricks in water can be understood by first having to study the behavior of the materials involved in brick masonry. The Basic materials involved in Brick Masonry are:-
1) Clay Bricks / Tiles
2) Cement-Sand Mortar
Brick is actually termed as any building material which is rectangular in shape; however usually the word clay is used for a construction material unit used to render a wall of brick masonry with the help of mortar.
|Why brick are soaked in water before lying in Brickwork?|
Mortar is a mixture of cement and sand that is mixed in suitable proportion with water to lay bricks / tiles or even do the plastering work for brick masonry or block masonry.
As we already know about cement that after addition of water with cement a hydration reaction takes place which converts it into a hard rock-like mass which takes a permanent shape in which it is placed.
Each of the four main cement minerals reacts at a different rate and tends to form different solid phases when it hydrates.
In order to ensure timely and proper hydration reaction it is ensured that sufficient water is applied to the concrete and that is the reason why we found jute cloth or standing water on the concrete slabs just after its casting process.
If this water is not applied in plenty the heat of hydration (heat generated during hydration reaction in cement) will cause cracks on the surface also called shrinkage cracks which may be deteriorating for the structure. Therefore it is always ensured to provide water in any form to the concrete.
Now the next construction material under consideration is Brick which is made of clay and as we know from the matrix of the clay material that is a porous structure having sufficient voids that creates brick a water absorbing giant.
Therefore if without soaking you will start laying bricks it will be, for sure, start absorbing the water from the cement sand mortar and in return the hydration will not properly took place which will make brick masonry a low strength and doubtful structure from strength point of view.
One more reason of soaking the brick in water is to clear the brick from any dirt and unwanted dust or mud etc. This will ensure proper bond between different bricks.