Building Material and Construction (BMC)

Notes on Building Material and Construction (in short form, BMC)

Common Building Materials from Building Material and Construction are

• Cement


• Lime


• Aggregates


• Mortar


• Admixture


• Concrete


• Bricks


• Stones


• Steel


• Timber


• Miscellaneous

Cement

• Cement is an organic building material with a binding property of construction that was invented by Mr. Joseph Aspedin in the years 1824-1825.


• Calcareous Compounds (Compounds containing Ca, Hg) and Argillaceous Compounds make up the majority of cement (Compounds having Silica, Aluminium Oxides)


• Examples of Calcareous Compounds are Limestones, Cement Rocks, Chalk, Marine Shell, Alkali Waste


• Examples of Argillaceous Compounds are the Clay, Slate, Ash


• OPC's Different Constituents (i.e Ordinary Portland Cement)
  
  
  
  • Lime (CaO - 62% to 67%)
    
    
    
    • It gives cement its strength and stability.
    
    
    • If there is so much lime in the mortar, it becomes unsound, allowing it to spread and then disintegrate.
    
    
    • A lack of lime decreases the strength of the cement and allows it to settle easily.
  
  
  • Silica (SiO2 - 17% to 25%)
    
    
    
    • If there is a surplus, the cement's strength increases, but the cement's setting time increases as well.
    
    
    • It also gives strength to the cement.
  
  
  • Alumina (Al2O3 - 3% to 8%)
    
    
    
    • It gives the cement a quick-setting property.
    
    
    • It serves as a flux, lowering the clinkering temperature.
    
    
    • It weakens the cement if there is an excessive amount of it.
  
  
  • Calcium Sulphate (CaSO4 - 3% to 4%)
    
    
    
    • It's usually added in the shape of gypsum, which is CaSO4-2H2O in most cases.
    
    
    • It aids in extending the cement's initial setting time.
  
  
  • Iron Oxide (Fe2O3 - 3% to 4%)
    
    
    
    • It gives cement its resilience, toughness, and color.
  
  
  • Magnesia (MgO - 1% to 3%)
    
    
    
    • It gives cement strength, toughness, and color, but too much of it renders the cement unsound.
  
  
  • Sulphur (S - 1% to 3%)
    
    
    
    • Sulphur in cement causes volume variations in the material, which causes it to be unstable.
  
  
  • Alkali (Na2O, K2O - 0.2% to 1%)
    
    
    
    • Alkalies in the cement produce efflorescence, which causes stains to appear on the surface of the structure in which it is used for building.
    
    
    • As alkalies react with aggregates, they expand, causing them to disintegrate.
    
    
    • Alkalies also help cement paste to set faster.

BOGUES COMPOUND

• As all the above-mentioned cement materials are intergraded and burned, they combine to create a complex chemical compound known as BOGUES COMPOUND, which is responsible for the cement's properties.

Thanks,

Kumar Bhanushali