Building Materials
Mortar & Concrete: Types, Uses, Preparation, Proportion, Admixtures and Applications
In civil engineering, mortar and concrete are two fundamental construction materials widely used in building works. For students of the ITI Draughtsman Civil trade, understanding these materials is essential for preparing accurate drawings and specifications. Both materials act as binding agents, but they differ in composition, strength, and applications.
Mortar
Mortar is a mixture of binding material (cement or lime), fine aggregate (sand), and water. It is primarily used to join bricks, stones, and blocks in masonry construction.
Types of Mortar
- Cement Mortar: Made with cement and sand; strong and durable.
- Lime Mortar: Made with lime and sand; flexible and workable.
- Gauged Mortar: Combination of cement and lime.
- Surkhi Mortar: Lime mixed with powdered burnt clay.
Uses of Mortar
- Bonding bricks and stones
- Plastering walls and ceilings
- Filling joints
- Providing smooth surface finish
Preparation of Mortar
Mortar is prepared by mixing cement (or lime) with sand in a specific proportion, followed by adding water to obtain a workable paste. Proper mixing ensures uniformity and strength.
Proportion of Mortar
- 1:3 (cement:sand) – high strength work
- 1:4 to 1:6 – general masonry
- Varies depending on type of work
Concrete
Concrete is a composite material made of cement, sand (fine aggregate), coarse aggregate, and water. It gains strength over time due to the chemical reaction known as hydration.
Types of Concrete
- Plain Cement Concrete (PCC): No reinforcement
- Reinforced Cement Concrete (RCC): Contains steel reinforcement
- Prestressed Concrete: High strength concrete with pre-applied stress
- Lightweight Concrete: Made using lightweight aggregates
Uses of Concrete
- Foundations and footings
- Beams, columns, and slabs
- Roads and pavements
- Bridges and dams
Preparation of Concrete
Concrete is prepared by mixing cement, sand, and aggregates in required proportions. Water is added to form a workable mix. Mixing can be done manually or using machines. Proper compaction and curing are essential to achieve strength.
Proportion of Concrete
- 1:2:4 – common mix for general construction
- 1:1.5:3 – higher strength concrete
- Designed mixes are used for specific requirements
Admixtures
Admixtures are materials added to mortar or concrete to improve their properties. They enhance workability, strength, durability, and setting time.
- Plasticizers: Improve workability
- Accelerators: Speed up setting
- Retarders: Slow down setting
- Waterproofing Agents: Reduce permeability
Applications
Mortar and concrete are used in almost all construction works. Mortar is mainly used for bonding and finishing, while concrete is used for structural strength.
- Building construction
- Infrastructure projects
- Repair and maintenance
- Decorative and finishing work
Conclusion
Mortar and concrete are essential building materials in civil engineering. Understanding their types, preparation, proportions, and applications is crucial for students of the Draughtsman Civil trade. Proper use of these materials ensures strength, durability, and quality in construction projects.