Definition of mortar | Its Functions And Properties |

Mortar is a paste, which is obtained by mixing binding materials like cement or lime and inert materials or fine aggregates like sand, surkhi, etc. along with water in varying proportions.

Mortar is used as a binding material in stone or brick masonry, or concrete, as a covering material to walls in the form of plasters to provide smooth, hard, and decorative surfaces. So, the strength, durability, and safety of the resulting wall or any structure depend on the quality of the mortar used as a binding medium.

Functions of Mortar:

·       It binds together or provides cohesion between the structural units (like brick, stone, etc.)

·       It forms a homogeneous mass of structure so that it may resist all the loads coming over it and transfer the loads uniformly to its foundation.

·       In all types of concrete, mortar holds coarse aggregates together, so as to form a solid mass.

·        In stone or brick masonry, it fills up empty joints, thus providing cohesion between the consecutive courses of brick. A thin liquid mortar used for such purposes is termed, Grout.

·       It provides a durable/weather resisting layers between different courses of masonry in the structure.

·       Mortar can protect the surface of the brick or stone masonry.

·       To improve the appearance of the structure through plastering. And plastering is one of the methods of applying mortar.

·       It does pointing or plastering to the structure.

(Pointing refers to the finishing of mortar joints in the masonry by covering rough walls and uneven surfaces with a plastic material called plaster, which is also called the mortar.)

 

Properties of a good mortar:

·       The mortar mix should be easily workable in the site condition – easily transported to the place of application.

·       The main quality that mortar should possess is: it should be capable of developing good adhesion to building units (bricks, Stones, etc.)

·       It should be capable of developing sufficient strength in compression, tension, and bond for the work for which it is used.

·       It should possess high durability and should be strong on drying. Also, it should not affect the durability of other materials.

·       It should set quickly so that construction could be accelerated.

·       It should be capable of binding the bricks or stones to give a tight joint through which water cannot penetrate.

·       It should be cheap.

·       Cracks should not be developed in the joints formed by the mortar and should be able to maintain their appearance for a long period.

·       It should possess sufficient plastic property due to which it can be easily placed on the bed of construction in the form of a thin, smooth, and uniform layer.

Mortars are usually named or classified according to the binding material used in their preparation. In general, mortars are classified as follows:

1.    Cement mortars

2.    Lime mortars

3.    Lime-cement mortars

4.    Special mortars

Ø Mud mortars

Ø Cement-clay mortars

Ø Gypsum mortars

Ø Decorative mortars

Ø Packing mortars

Ø Fire resisting mortars