Cement Mortar is defined as the homogeneous mixture of cement, sand and water in a suitable proportion. Sometimes the addition of admixture is required in the mortar to make it more resistive towards water and chemicals.
Grades of Cement Mortar
|Grade Name||Mix (by Loose Volume)||Compressive Strength at 28 days (in N/mm2)|
|MM 0.7||1||8||0.7 to 1.5|
|MM 1.5||1||7||1.5 to 2.0|
|MM 3||1||6||3.0 to 5.0|
|MM 5||1||5||5.0 to 7.5|
|MM 7.5||1||4||7.5 to above|
Properties of Cement Mortar
~ It should be easily workable.
~ It should develop adequate strength in tension, compression, and bond for the work.
~ It should be durable.
~ It should not affect the durability of other materials.
~ It should set quickly so that the speed of construction is ensured.
~ It should be cheaply available.
~ It should bind the bricks or stones to give a tight joint through which water cannot penetrate.
~ The joints form by mortar should not develop cracks and they should be able to maintain their appearance for quite a long time.
Uses of Cement Mortar:
~ It is used to fill up a gap between the brick and stone for making wall weather tight.
~ It is used to give soft even bed between the different layer of brick and stone masonry for equal distribution of pressure over the bridge.
~ It is used in pointing and plastering to protect joints and surface of bricks and stone masonry.
~ It is used to fill up the joints of pipes.
~ It is used to generate the appearance of the structure.
~ It is used to hide the open joints of brickwork or stonework.
Preparation of Cement Mortar
a. Selection of Materials
Cement, sand and water are the materials required for the preparation of cement mortar. Strong, sound and durable sand and cement should be used. Water having ph value 6 or less is not suitable in mortar preparation.
b. Mixing of Materials
Mix the materials (cement, sand and water in suitable proportion) manually or by the use of a mixer. This mixture is a cement mortar.
c. Transporting and Placing of Mortar
Transport the mortar to the required place by using wheelbarrow or by using mortar pump. Then place or apply the mortar to the required surface.
Curing of this mortar is generally done for 7 to 14 days. It increases the strength of mortar and reduces future problems like cracking.
|Read Also: Grades of Concrete|