Portland Cement Clinker
1 – Clinker Mineralogy .
a – The phases which should theoretically be present in a cooled clinker of this composition .
b – The quantity of each phase which should be present :
I – C3S
II – C2S
III – C3A
IV – C4AF
Phase diagram CaO-SiO2-Al2O3 .
Phase diagram CaO-SiO2-Al2O3-Fe2O3
2 – Real Clinker Minerals .
What are the real chemical compositions of the clinker minerals ?
Pure compounds C3S , C2S , C3A not occur in this simple form , but contain oxides such as MgO , Na2O , K2O , Fe2O3 and Al2O3 .
Using analytical techniques :
a – Electron microprobe analyzer .
b – Energy dispersive analyzer .
Polymorphic modification of clinker minerals
We find that not only chemical composition vary clinker minerals , but some clinker phase also exist in different polymorphic forms , which can exhibit different physical properties .
a - C3S alite
Have 6 polymorphic modification between room temperature and 11000C . The changing appear in the lattice structure .
b - C2S belite ( β-C2S ) .
Have 5 modifications between room temperature and 15000C (γ , β ,α) . The change β to γ and γ to α are irreversible and slow .
c - C3A .
C3A present as a cubic lattice , but Na2O are incorporated within the lattice forming orthorhombic , monoclinic and tetragonal modification but they differ in their reactivates .
d - C4AF .
Pure C4AF is not found .
Quantitative clinker mineralogy
A – Calculation of potential clinker composition . By Bogue , which consider chemical equilibrium has been attained .
1 – Fe2O3+Al2O3+CaO= C4AF
2 - Al2O3+CaO= C3A
3 – SO3+CaO=CaSO4
4 – CaO+SiO2= C2S
5 - C2S+CaO= C3S
6 – MgO free .
# C3S=4.07*CaO-7.6*SiO2-6.72*Al2O3-1.43*Fe2O3-2.85*SO3

#C2S=2.87*SiO2-.754*C3S