Advanced Concrete Technology
Unit – 1
Cement- The hidden material
Hidden around us all the time but we hardly notice it
Super-material, strange structure, many uses namely,
What is cement?
Cement, any material that hardens and becomes strongly adhesive after
Manufactured substance consisting of gypsum plaster, or Portland cement
Portland cement hardens and adheres after being mixed with water
History of Cement:
The term “Portland cement” was first used in 1824 by Joseph Aspdin, a British
cement-maker, because of the resemblance between concrete made from his
cement and Portland stone, which was commonly used in building in Britain.
The first modern Portland cement, made from lime and clay materials heated
until they formed clinkers was produced by Isaac Charles Johnson in Britain in
At that time cements were usually made in upright kilns where the raw
materials were spread between layers of coke, which was then burnt.
The first rotary kilns were introduced about 1880. Portland cement is now
almost universally used for structural concrete.
How is it made?
Limestone for calcium and Clay or shale for Silica/Alumina is used as raw
The manufacturing process of Portland cement clinker consist essentially of
grinding the raw materials, mixing them in appropriate proportion, burning the
raw material in a kiln at a temperature of 1400-1500 oC until material partially
fuses into balls known as clinker and grinding to cooled clinker together with a
small amount of gypsum rock.
The mixture of raw material is burned in a rotary kiln.