Concrete has a wide application in construction across various parts of a building – from foundation to columns to roof, because it can be formed into various shapes. Concrete blocks are precast masonry units which are rectangular in shape and made with plain cement concrete of a lean mix-proportion that ranges from 1:9 to 1:13 (1 part of cement: 13 parts of sand and stone aggregates). In addition to the basic components, the concrete for making blocks may also contain additives like admixtures to increase compressive strength, or improve work ability. They have also been produced with improved textures for better durability and appearance using stone ships or glazed surfaces. Concrete blocks have been in use in India for nearly three decades and are commonly found in all parts of the country- both rural and urban. They also owe their popularity to the fact that speed of construction is enhanced since the blocks could be 5-10 times bigger than burnt bricks. Commonly available dimensions are length 200-400 mm, width 100 or 200 mm and height 150-200 mm. Both solid and hollow blocks are made – generally hollow blocks are used for partition walls.
Advantages of hollow concrete blocks
Highly Durable: The good concrete compacted by high pressure and vibration gives strength to the block. Proper curing increase compressive strength of the blocks.
Low Maintenance, Color and brilliance of masonry withstands outdoor elements.
Load Bearing, strength can be specified as per the requirement.
Provide thermal and sound insulation: The air in hollow of the block, does not allow outside heat or cold in the house. So it keeps house cool in summer and warm in winter.
Environment Friendly, fly ash used as one of the raw materials. Low insurance rates.
In this construction system, structurally, each wall and slab behaves as a shear wall and a diaphragm respectively, reducing the vulnerability of disastrous damage to the structure/building, during the natural hazards.
Due to the uniform distribution of reinforcement in both vertical and horizontal directions, through each masonry element, increased tensile resistance and ductile behaviour of elements could be achieved. Hence, this construction system can safely resist lateral or cyclic loading, when compared to other conventional masonry construction systems. This construction system has also been proved to offer better resistance under dynamic loading, when compared to other conventional systems of construction.
No additional formwork or any special construction machinery is required for reinforcing the hollow block masonry.
Only semi-skilled labour is required for this type of construction. It is a faster and easier construction system, when compared to the other conventional construction systems.
It is also found to be a cost-effective disaster resistant construction system, as explained in the next section.
Architectural & other advantages
This construction system provides better acoustic and thermal insulation for the building. This system is durable and maintenance free.
Reduction in Dead Load
- Reduced Air Conducting Load: – Approx.50% saving.
- No salt peter or leaching: – Reduction in maintenance.
- Increased carpet area: – Due to smaller in size.
- Faster construction: – Easy to work with bigger in size.
- Assured Quality: – Fully automatic block plant.
- Better sound absorption: – Being hollow in nature.
- Reduced thickness of plaster: – Due to size accuracy & less cement consumption due to fewer joints.
- Load bearing walls: – Due to higher strength of blocks. Recommended for earth quake resistance.
- Less water absorption: – Approx. 3 to 4% Environmental Eco-Friendly.
- Reduce in total cost of project: – Being less dead load of walls.