Mortar || Introduction || Types || Function || Properties

Mortar 

1. It is a workable paste which is a mixture of sand, cement, lime  stone, dust, water, etc.  
2. It is used to bind building blocks such as stone, brick, concrete, etc.  together. 
3. It is used to fill the tracks, holds, etc.  
4. In the vast area we use pitch, asphalt, and soft mud and clay as mortar with brick.What is mortar used for 
5. The word mortar originated from the Latin word morterium which means crushed.
6. Nowadays we use Portland cement to make mortar which is called cement mortar, but in olden times lime was used to make mortar which is called lime mortar.Mortar gun 
7. Lime mortar was used in making special buildings and monuments.

Types of mortar 

1. Cement mortar 
2. Lime mortar 
3. Surkhi mortar 
4. Gauge mortar 
5. Gypsum mortar 

1. Cement mortar 

The type of mortar in which cement is used as a binding material and sand as fine aggregate with water, called as a cement mortar. Cement mortar ratio and uses 

1. Cement mortar has more strength, and it can be used in water logged area. 
2. Cement mortar is used in large area like masonry works, patching, filling, plastering, floor levelling, repairing damaged concrete, rendering, and development of precast products. 
3. Fine aggregate of 2 mm size is used in cement mortar. 
4. Generally the ratio of cement to sand is 1:2 and 1:6 in the cement mortar, and the ratio of cement to sand depends on what kind of work it is being used in. 
5. Cement and water are set and harden due to a special chemical process called hydration. 
6. There are different types of cement available in market but generally Portland cement is used for masonry works.

2. Lime mortar 

The type of mortar in which lime is used as a binding material is called as lime mortar. 

The assumption behind using lime mortar was that after it evaporates water and absorb carbon dioxide present in the atmosphere it becomes hard and strong, but it was only theoretically correct. Actually it took a very long time to strengthen.

Lime may be two types :-

A. Fat lime 

B. Hydraulic lime 

A. Fat lime 

The lime which has 95% pure calcium oxide  (Cao) and less than 7.5 % clay is called fat lime. 

It shrinks  to greater extend so, it is used two to three times of volume of sand. It is used in plaster work, painting work, distempering, etc. 

B. Hydraulic lime 

The lime in which more than 7.5 % clay and remaining pure calcium oxide (Cao) is found called as hydraulic lime. 

1. It is used in mortar in ratio 1:2. 
2. Hydraulic lime has more strength than fat lime. 
3. Fat lime is not used in damp conduction but hydraulic lime may be used in damp conduction. 
4. Hydraulic lime is used in foundation, brick work in super structure, etc.  

3. Surkhi mortar 

The type of mortar in which surkhi is used as fine aggregate in instead of sand lime / cement is used as a binding material is called as surkhi mortar. Surkhi mortar uses and ratio 

1. Surkhi powder is sieve through I. S. no. - 9 , so that the residue left is not more than 10% . 
2. In England, surkhi are also known as trass or brick-dust. 
3. Surkhi are not used in plastering and pointing because after some time it springs. Mud mortar 
4. It is used only in general work such as foundations and super structures.
5. Use of surkhi is useful in sea water construction.
6. It is used in some of the largest dams and mass structures in India in association with cement concrete as an admixture.Advantages and disadvantages of surkhi mortar 
7. This reduces the temperature produced during the formation of mass cement concrete, and also reduced cracking.

4. Gauge  mortar 

The type of mortar in which cement is used to improve the quality of lime mortar and to achieve early strength of lime mortar is called as gauge mortar. Gauged mortar uses and ratio 

•  The process of mixing cement with lime is called as gauging and mortar obtained called gauge mortar. 

5. Gypsum mortar 

The type of mortar in which gypsum is used as a binding material, sand as fine aggregate is called gypsum mortar. Gypsum mortar  mix ratio 

1. It is also known as plaster of Paris.  
2. It is used in historical or monumental building. 
3. The plaster of paris was used to repair structures. 
4. It was used by the Egyptians in building the pyramid.
5. It was also used to rebuild the city of Paris.
6. Gypsum does not form hydrates, due to which it is stable even in water.Gypsum mortar uses 

Function of mortars

1. It is used to fill the gap / cracks in building. 
2. To bind building unit, such as bricks, stone, concrete block, etc. to act as a single unit. 
3. To provide strength to the building unit to resist  vertical and horizontal load. 
4. To provide weatherproof property. 
5. Mortar is used to fill the empty space or irregular shape present in the brick masonry or block masonry.
6. In this, we decorate the brick masonry by mixing different colors or making a pattern.Application of mortar 

Properties of mortar 

1. The mortar should have greater adhesion properties, so that, it can joint two or more component  strongly. Properties of mortar in masonry 
2. Mortar should be economically. 
3. It should resist penetration of water. 
4. Mortar should be desirable. 
5. It should resist  weathering action due to neutral force.
6. When the mortar is cured, it becomes hard, and takes the form of rigid structures.
7. The mortar mix should be workable, meaning it can be used easily and can be easily transported to the construction site.
8. To form joints of pipes.Properties of good mortar 
9. It should be set and hardened easily and quickly to speed up the construction speed.
10. It should have the ability to develop a designed stress.