Concrete blocks, also known as concrete masonry units (CMUs), are standard rectangular blocks used in construction, produced in automated or manual plants. They are made by mixing aggregates, cement, and water, molded, and cured to enhance strength, and are classified into solid and hollow blocks with various applications. Advantages include improved thermal insulation and quicker construction, while disadvantages involve potential cracking, shrinkage, and higher costs.

1. BLOCKS
CONCRETE BLOCKS.

2. CONTENTS:
• Introduction
• Manufacturing
• Types
• Advantages
• Disadvantages
• Uses

3. INTRODUCTION
• It is a standard size rectangular block used in building construction.
• Also known as “Concrete masonry unit (CMU)”.
• Concrete blocks are precast.
• Mostly concrete blocks have one or more cavities and their sides may be smooth
or contain a design.
• Concrete blocks are held together with fresh concrete mortar.

4. MANUFACTURING OF CONCRETE BLOCKS
• Concrete blocks are manufactured in fully automatic plants which produces
concrete blocks of superior quality and high strength
• Production of concrete blocks in such plants is expensive.
• Manually operated machines are also available which can be installed at project
site itself.
• Manually operated machines reduces the transportation cost of concrete blocks.
• It is manufactured in 4 steps:

5. 1.SELECTION AND PROPORTION OF INGREDIENTS
• Concrete blocks are made up of aggregates (fine and coarse), cement and water.
• Ingredients are selected according to the desired strength.
• Strength, texture and economy of concrete blocks depends upon the careful grading of
aggregates.
• Crushed stones, gravel, volcanic cinders and furnace clinker etc. are used as aggregates.
• Aggregates are selected by considering the weight, texture or composition of unit designed.
• Cement used is ordinary Portland cement.
• Water required is normal potable water

6. 2.MIXING OF INGREDIENTS
• Blending of aggregates, cement and water should be done
very carefully.
• It is better to mix the ingredients in a mechanical mixer.
• Extreme care should be taken for hand mixing (Dry mixing).

7. 3.MOLDING
• The concrete mix is fed into the mold box up to top level.
• It is ensured that the box is filled up to top level.
• Vibration of concrete is done till it has uniformly settled in the mold box,
• Excess concrete mixture is removed from the face of mold and levelled by using
plywood.
• Concrete mixture used for blocks contain higher %age of sand and lower %age of
gravel and water than the concrete mixtures used for general construction
purposes.This produces a very dry, stiff mixture that holds its shape when it is
removed from the block mold.

8. 4.CURING
• The block is watered after about one day of casting.
• Curing is continued for minimum 7 days and maximum 28 days.
• Longer the curing period, better will be the block.

9. TYPES OF CONCRETE BLOCKS
• Classified into 2 types:
• 1. Solid Concrete Blocks:
-Heavy in weight.
-Manufactured from dense aggregate.
-Very strong and makes the structure very stable.
-Preferable to be used in load bearing walls.
-Available in large sizes than bricks, hence less time is required for construction.

10. 2. Hollow Concrete Blocks:
-Contain voids greater than 25% of total area.
-Solid area should be more than 50%.
-Manufactured from lightweight aggerate.
-Light weight blocks and are easy to install.
TYPES OF CONCRETE BLOCKS

11. TYPES OF HOLLOW CONCRETE BLOCKS
• Stretcher block
• Corner block
• Pillar block
• Jamb block
• Partition block
• Lintel block
• Frogged brick block
• Bull nose block

12. • Stretcher Block: • Corner block:

13. • Pillar Block: • Jamb Block:

14. • Partition Block: • Lintel Block:

15. • Frogged Brick Block: • Bull Nose Block:

16. ADVANTAGES
• Its width is less than bricks due to which carpet area increases.
• Better thermal insulation, fire resistance and sound absorption.
• Saves precious agricultural lands which are used for manufacturing bricks.
• Construction of blocks is easier, faster and is stronger than brick.
• Perfect shape makes the masonry work very simpler.
• No real need for plastering.
• Environment friendly.

17. DISADVANTAGES
• Wider and larger cracks.
• Shrinkage due to movement of moisture.
• Expensive.
• Plumbing issues.

18. USES
• Retaining walls, to keep soil and water away from certain areas.
• Security Barriers.
• Buildings and houses.

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