what is chemical composition of cement?
""Question 74""
""brief description""
The raw materials used for the manufacture of cement consist mainly of lime, silica, alumina and iron oxide. These oxides interact with one another in the kiln at high temperature to form more complex compounds. The relative proportions of these oxide compositions are responsible for influencing the various properties of cement; in addition to rate of cooling and fineness of grinding.
Approximate Oxide Composition Limits of Ordinary Portland Cement
Oxide Per cent content
CaO 60–67
SiO2 17–25
Al2O3 3.0–8.0
Fe2O3 0.5–6.0
MgO 0.1–4.0
Alkalies ( K2O, Na2O) 0.4–1.3
SO3 1.3–3.0
The identification of the major compounds of cement is largely based on Bogue’s equations and hence it is called “Bogue’s Compounds”. The four compounds usually regarded as major compounds are listed in below.
Major compounds of cement
Name of Compound Formula
Tricalcium silicate 3 CaO.SiO2
Dicalcium silicate 2 CaO.SiO2
Tricalcium aluminate 3 CaO.Al2O3
Tetracalcium 4CaO.Al2O3.Fe2O3
aluminoferrite
It is to be noted that for simplicity’s sake abbreviated notations are used. C stands for CaO, S stands for SiO2, A for Al2O3, F for Fe2O3 and H for H2O.
The equations suggested by Bogue for calculating the percentages of major compounds are given below.
C3S = 4.07 (CaO) – 7.60 (SiO2) – 6.72 (Al2O3) – 1.43 (Fe2O3) – 2.85 (SO3)
C2S = 2.87 (SiO2) – 0.754 (3CaO.SiO2)
C3A = 2.65 (Al2O3) – 1.69 (Fe2O3)
C4AF= 3.04 (Fe2O3)
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Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings..........