Concrete Blocks | Construction Materials | By Ashutosh Nautiyal

Introduction Of Concrete Blocks:- Concrete block is also called a Concrete Masonry Unit(CMU). A Concrete block is primarily used as a building material in the construction of walls. A concrete masonry unit(CMU) is a standard size rectangular block used in building construction.

Concrete Blocks





Concrete Blocks | Construction Materials | By Ashutosh Nautiyal
Concrete Blocks




Introduction Of Concrete Blocks:-



  • Concrete block is also called a Concrete Masonry Unit (CMU).

  • A Concrete block is primarily used as a building material in the construction of walls.

  • A concrete masonry unit (CMU) is a standard size rectangular block used in building construction.

  • A Concrete block is one of the precast concrete products used in construction.

  • CMUs are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them.

  • Concrete blocks are produced in a large variety of shapes and sizes.

  • The first hollow concrete block was designed in 1890 by Harmon S. Palmer in the United States.

  • The concrete commonly used to make concrete blocks is a mixture of powdered portland cement, water, sand and gravel. 

  • Concrete block construction has gained importance and has become a valid alternative to fire clay bricks.

  • They can be produced manually or with the help of machines.

  • Concrete blocks may be produced with hollow centres to reduce weight or improve insulation.

  • The common size of concrete blocks is 39 cm * 19 cm * (30 cm or 20 cm or 10 cm) or 2 inch, 4 inch, 6 inch, 8 inch, 10 inch and 12-inch unit confirmation. 

  • Most concrete blocks have one or more hollow cavities, and their sides may be cast smooth or with a design.

  • In use, concrete blocks are stacked one at a time and held together with fresh concrete mortar to form the desired length and height of the wall.

  • Today, concrete block manufacturing is a highly automated process that can produce up to 2000 blocks per hour.

  • Most commonly used concrete blocks are sized:-

  • Length- 40 cm (half blocks: 20 cm)

  • Height- 20 cm 


  • Width - 8/10/15/20 cm 

Concrete Blocks | Construction Materials | By Ashutosh Nautiyal
Concrete Blocks


  • Solid concrete blocks have no cavities or according to the US standards have no voids amounting to not more than 25% of the gross cross-sectional area.



  • Hollow concrete blocks are the most common type of concrete blocks which are having one or more holes that are open at both sides.



  • The total void area for hollow blocks can amount to 50% of the gross cross-sectional area.



Advantages Of Concrete Blocks:-



Technical Advantages:-



Solid Blocks:-




  • They have high compressive strength, resistance to weathering, impact and abrasion.



  • They have the capability of being moulded into components of any shape and size.



  • They have good fire resistance up to about 400°C.



  • They facilitate rapid construction. 



  • They are having very good stability.



Hollow Blocks:- 




  • They can be made larger than the solid blocks.



  • They are lighter in weight.



  • They facilitate easy and quick construction of walls.



  • Their voids can be filled with steel bars and concrete because of which they acquire high earthquake resistance.



  • The air space in them provides good thermal insulation.



  • The cavities in them can be used for electrical installation for pumping.



Economic Advantages:-




  • The production of concrete blocks can be started with little capital.



  • With concrete blocks, less working time is required for bricklaying work.



  • There is less mortar consumption with concrete blocks.



  • Generally, the production cost of concrete blocks is slightly lower than that of fire bricks.



Limits Of Applications Of Concrete Blocks:-




  • Raw materials of good quality and economically feasible must be locally available.



  • A relatively large amount of cement is needed, which can be expensive and difficult to obtain.



  • Special knowledge and experience of the production process are needed.



Raw Materials For Concrete Blocks:- 



Cement:- 




  • Ordinary Portland Cement 



  • Special cements



Aggregate:-




  • Sand or gravel



  • The maximum particle size of the coarser aggregate is 10 mm.


  • Suitable aggregates are usually obtained from natural sources(river bed, gravel pits, volcanic deposits) or from industrial by-processes(granulated blast furnace slag, sintered fly ash).



Cement-Aggregate Ratio:-




  • A suitable proportion of aggregate to cement must be found by testing.



  • Common ratios are 1:6 and 1:8.



  • Test the quality of blocks produced.



Water-Cement Ratio:-




  • Only drinking quality water should be used to mix the concrete.



  • Recommended water-cement ratio is 0.5.



Equipment Used For Production Process Of Concrete Blocks:-




  • Masonry tools



  • Mixers: Pan mixers; Trough mixers



  • Blockmaking machine: Hand-operated; "Egg-laying" mobile machines; fully mechanised stationary machines.



Production Process Of Concrete Blocks:-



Batching And Mixing:-




  • Batch aggregates and cement by weight.



  • Mix cement and aggregates using mattock, shovel or mixer until it reaches homogeneous condition.


  • Add some water.



  • In hot climates, the fresh mix must be shaded from the sun.



Moulding:-




  • Put the mixture into wooden or steel mould boxes or moulding machine.



  • Demould blocks immediately after compaction.



Curing:- 




  • Cover the demoulded bricks with plastic sheets for 24 hours.



  • Keep the concrete blocks moist by keeping underwater in tanks or by regularly spraying with water for 7 days.



Storing:- 




  • Don't expose to direct sunlight; keep the blocks in a dry and covered area.



  • Store for 2 weeks before using.



Skills Required For Production Process:-




  • Concrete making and masonry skills. 


Lightweight Concrete Blocks



  • Lightweight concrete block is a concrete masonry unit(CMU) made of expanded aggregate to reduce the density and weight compared to standard concrete blocks.

  • Lightweight concrete blocks are made by replacing the sand and gravel with expanded clay, shale, or slate. 

  • The light weight concrete blocks can help reduce heavy lifting and carrying by minimizing the weight of the concrete blocks that must be lifted and carried during brick-laying tasks.

  • Using lightweight concrete block reduces strain and loading on mason's backs.










*Self Typed
*Source- Internet, Books, Self-Analysis




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About the Author

Mr. Ashutosh Nautiyal is a student who is pursuing his post-graduation (MBA in Infrastructure Development and Management) from SCMHRD, Pune. He has done his B.Tech in Civil Engineering from BTKIT, Dwarahat and his schooling from Omkarananda Saraswat…

2 comments

  1. Thanks Mr. Happy
  2. Helpful content. Thank you for sharing information about Readymade Compound Wall. Keep posting!!
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