This educational science and technology animation shows the concept of production, composition and setting of cement and all the chemical reactions involved in the processes; mortar and concrete are also touched upon. This is very useful for K9 -K12 students, teachers and for the industry people for understanding how cement works.
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The term cement is also commonly
used to refer more specifically to powdered materials which
develop strong adhesive qualities when combined with water.
Cement is made by mixing substances containing lime, silica,
alumina, and iron oxide and then heating the mixture until
it almost fuses. Cement consists of particles containing
compounds of calcium (Ca), iron (Fe), aluminium (Al), silicon
(Si) and oxygen (O) in varying proportion.
The main four raw material of cements are: 60% to 67% CaO,
17% to 25% SiO2, 3% to 8% Al2O3, up to 6% Fe2O3 and small
amounts of magnesium oxide, magnesium sulfate, sodium and
potassium oxides.
Chemical constituents of cement is
54% |
Tricalcium silicate (3CaO.SiO2) |
(C3S) |
16% |
Dicalcium silicate (2CaO.SiO2) |
(C2S) |
11% |
Tricalcium aluminate (3CaO.Al2O3) |
(C3A) |
9% |
Tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3) |
(C4AF) |
During the heating process dicalcium and tricalcium silicate,
tricalcium aluminate, and a solid solution containing iron
are formed. Gypsum is later added to these products during
a grinding process.
Cement with a high aluminate content is used for fireproofing,
because it is quick-setting and resistant to high temperatures;
cement with a high sulfate content is used in complex castings,
because it expands upon hardening, filling small spaces.
Cement is usually mixed with other substance. Mortar is
a mixture of cement, sand, water and lime. Concrete is a
mixture of cement, sand and crushed stones.
All about it inside the animation.
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