Cement: Composition & Classification
A Technical Overview of Binding Materials in Construction
1. Introduction to Cement
Cement is a binder, a substance used for construction that sets, hardens, and
adheres to other materials to bind them together. Cement is seldom used on its own,
but rather to bind sand and gravel (aggregate) together. Cement mixed with fine
aggregate produces mortar for masonry, or with sand and gravel, produces concrete.
2. Chemical Composition
The raw materials used in the manufacture of cement consist mainly of lime, silica,
alumina, and iron oxide. These compounds interact with one another in the kiln to
form a series of more complex products.
Percentage
Ingredient Function
(%)
Lime (CaO) 60 - 67 Controls strength and soundness.
Provides strength due to formation of
Silica (SiO₂) 17 - 25
dicalcium and tricalcium silicates.
Alumina (Al₂O₃) 3-8 Imparts quick setting property.
Iron Oxide
0.5 - 6 Provides color and acts as a flux.
(Fe₂O₃)
Gypsum (CaSO₄.
2-3 Retards the initial setting time.
2H₂O)
A Technical Overview of Binding Materials in Construction
1. Introduction to Cement
Cement is a binder, a substance used for construction that sets, hardens, and
adheres to other materials to bind them together. Cement is seldom used on its own,
but rather to bind sand and gravel (aggregate) together. Cement mixed with fine
aggregate produces mortar for masonry, or with sand and gravel, produces concrete.
2. Chemical Composition
The raw materials used in the manufacture of cement consist mainly of lime, silica,
alumina, and iron oxide. These compounds interact with one another in the kiln to
form a series of more complex products.
Percentage
Ingredient Function
(%)
Lime (CaO) 60 - 67 Controls strength and soundness.
Provides strength due to formation of
Silica (SiO₂) 17 - 25
dicalcium and tricalcium silicates.
Alumina (Al₂O₃) 3-8 Imparts quick setting property.
Iron Oxide
0.5 - 6 Provides color and acts as a flux.
(Fe₂O₃)
Gypsum (CaSO₄.
2-3 Retards the initial setting time.
2H₂O)
