The mortar is a paste made by combining lime, surkhi, and water; or lime, sand, and water; or cement, sand, and water. The lime and cement act as binding materials, whereas the sand and surkhi prevent shrinkage and cracking during the setting process, giving the mortar its strength.
Classification of Mortar
The classification of mortar is carried out on the basis of following features of the building mortar.
- Bulk Density
- Binding Material
- Application
- Physical & Mechanical Properties
Bulk Density
Heavy and light weight mortars are classified according to their bulk density.
| Type of Mortar | Bulk Density (kg/m³) | Aggregate |
| Light Weight | < 1500 | Sand or Heavy Quartz |
| Heavy Weight | > 1500 | Light weight porous sand from slags, pumice etc. |
Binding Material
The governing elements in selecting on a specific type of mortar for a specific construction are the necessary masonry strength, resistance to rain water penetration, quick and long-term appearance, hardening temperature, predicted building working circumstances, and cost.
For the most part, a building mortar will fall into one of the following categories mentioned below:
- Lime Mortars
- Cement Mortars
- Gypsum Mortars
- Mud Mortars
- Composite Mortars
Lime Mortar:
Lime mortars are made from a combination of air hardening lime or hydraulic lime, sand, and water.
Cement Mortar:
Portland cement or its variants, sand, and water are used to make cement mortars.
Gypsum Mortar:
Gypsum mortars are made with gypsum or anhydride binding materials.
Mud Mortar:
Gypsum mortars are made from clay nodules and are used in the construction of houses for low-cost or temporary construction.
Composite Mortar:
Surkhi-motar (surkhi, lime, and water mortar), lime-surkhi-sand mortar, cement-lime mortar, and cement-clay mortar are all types of composite mortars.
Also Read : Characteristics of Good Mortar
Applications
There are various types of applications of mortars on which the classification can be done.
- Special mortars are used for acoustics, X-ray shielding, plugging concrete in oil fields, and other applications.
- Brick laying mortars are designed for use in bricklaying.
- Finishing mortars are used to apply decorative layers to walls and panels, as well as for architectural or ornamental elements.
Physical and Mechanical Properties
The strength of concrete, which underpins its durability, serves as the foundation for this type of classification. The compressive strength of building mortars is split into nine categories, ranging from 0.4 to 30.0 N/mm².
Uses of Mortar
The building mortar can be used for various purpose in construction industry. The main uses of mortar are mentioned below.
- It is used in vertical joints in brick and stone masonry and is spread over each layer to provide a binding medium for successive layers of masonry.
- In plastering and pointing, exposed walls and joints are covered with mortar to protect against weathering and to improve appearance.
- It is also used in concrete as a matrix.