By no means complicated , cement is simply a material to hold together materials !!! Technically speaking , Cement is the generic name of all those materials which initially have plastic flow , but when it is mixed with water or any other suitable liquid , forms a rigid - continuous mixture which solidifies on standing and when solidified has the capability to resist high compressive strengths .
The most common type of cement is PORTLAND CEMENT !!! Way back in 1824 , an Englishman named JOSEPH ASPDIN patented portland cement . He obtained it by the calcination of an argillaceous limestone . He named it PORTLAND as synonymous to a type of rock found at the Isle Of Portland , famous for it's strength . One to think that this was the start for mankind's construction glue :P is wrong , cause centuries ago Romans built the famous "Colosseum" using a cement like material called POZZOLANS !!! pretty impressive huh ;)
Basically , Cement can be summerised as a mixture of finely ground calcium silicates and aluminates of varying compositions , which decide the properties of that particular variety of cement . The main constituents of cement can be summed up into four varieties :
1) C2S
2) C3S
3) C3A
4) C4AF
Where ,
C = CaO
S = SiO2
A = Al2O3
F = Fe2O3
Varying these % 's can lead to different types of Portland cements namely :-
A ) TYPE - I : REGULAR
It has the following composition :
55% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 2.8% MgO, 2.9% (SO3), 1.0% Ignition loss,
and 1.0% free CaO.
It is used for general construction purposes . It gains it's full strength in 28 days .
B ) TYPE - II : MODIFIED
It has the following composition :
51% (C3S), 24% (C2S), 6% (C3A), 11% (C4AF), 2.9% MgO, 2.5% (SO3), 0.8% Ignition loss,
and 1.0% free CaO.
The higher C2S composition makes the cement moderately sulfate resistant and also
it has a moderate heat- of-hydration value .
It is used specifically in places where the sulfur content in the soil is high .
C) TYPE - III : HIGH EARLY STRENGTH
It has the following composition :
57% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 3.0% MgO, 3.1% (SO3), 0.9% Ignition loss,
and 1.3% free CaO.
It has the ability to attain the strength of Type - I cement in just 3 days , but due
to the high % of C3S and C3A " together" can be devastating and can cause high
values of Heat-of-Hydration , thus long-time strength has to be sacrificed . Thus , it
is useless for massive construction works .
Used only for emergency constructions where we do not have much time to wait
for it to stand to gain strength .
D) TYPE - IV : LOW HEAT
It has the following composition :
28% (C3S), 49% (C2S), 4% (C3A), 12% (C4AF), 1.8% MgO, 1.9% (SO3), 0.9% Ignition loss,
and 0.8% free CaO.
Notice the lower % of C3S and C3A , which are the major contributors of heat-of-
hydration . Consequently , the % of C4AF and other aggregates have to be increased.
Only drawback is that the time required to gain full strength is high when compared
to normal cement .
It is used for massive construction works like dams , etc .
E ) TYPE - V : SULFATE RESISTANT
It has the following composition :
38% (C3S), 43% (C2S), 4% (C3A), 9% (C4AF), 1.9% MgO, 1.8% (SO3), 0.9% Ignition loss,
and 0.8% free CaO.
This kind of cement has the highest % composition of C2S , thus making it highly
sulfate resistant .
Used in places nearby to the sea , as it resists sea contact very well .
Preparation of cement is a two step process ...The real game's still on......Keep logged into this site for an overview into it soon ;)
The most common type of cement is PORTLAND CEMENT !!! Way back in 1824 , an Englishman named JOSEPH ASPDIN patented portland cement . He obtained it by the calcination of an argillaceous limestone . He named it PORTLAND as synonymous to a type of rock found at the Isle Of Portland , famous for it's strength . One to think that this was the start for mankind's construction glue :P is wrong , cause centuries ago Romans built the famous "Colosseum" using a cement like material called POZZOLANS !!! pretty impressive huh ;)
Basically , Cement can be summerised as a mixture of finely ground calcium silicates and aluminates of varying compositions , which decide the properties of that particular variety of cement . The main constituents of cement can be summed up into four varieties :
1) C2S
2) C3S
3) C3A
4) C4AF
Where ,
C = CaO
S = SiO2
A = Al2O3
F = Fe2O3
Varying these % 's can lead to different types of Portland cements namely :-
A ) TYPE - I : REGULAR
It has the following composition :
55% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 2.8% MgO, 2.9% (SO3), 1.0% Ignition loss,
and 1.0% free CaO.
It is used for general construction purposes . It gains it's full strength in 28 days .
B ) TYPE - II : MODIFIED
It has the following composition :
51% (C3S), 24% (C2S), 6% (C3A), 11% (C4AF), 2.9% MgO, 2.5% (SO3), 0.8% Ignition loss,
and 1.0% free CaO.
The higher C2S composition makes the cement moderately sulfate resistant and also
it has a moderate heat- of-hydration value .
It is used specifically in places where the sulfur content in the soil is high .
It has the following composition :
57% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 3.0% MgO, 3.1% (SO3), 0.9% Ignition loss,
and 1.3% free CaO.
It has the ability to attain the strength of Type - I cement in just 3 days , but due
to the high % of C3S and C3A " together" can be devastating and can cause high
values of Heat-of-Hydration , thus long-time strength has to be sacrificed . Thus , it
is useless for massive construction works .
Used only for emergency constructions where we do not have much time to wait
for it to stand to gain strength .
It has the following composition :
28% (C3S), 49% (C2S), 4% (C3A), 12% (C4AF), 1.8% MgO, 1.9% (SO3), 0.9% Ignition loss,
and 0.8% free CaO.
Notice the lower % of C3S and C3A , which are the major contributors of heat-of-
hydration . Consequently , the % of C4AF and other aggregates have to be increased.
Only drawback is that the time required to gain full strength is high when compared
to normal cement .
It is used for massive construction works like dams , etc .
E ) TYPE - V : SULFATE RESISTANT
It has the following composition :
38% (C3S), 43% (C2S), 4% (C3A), 9% (C4AF), 1.9% MgO, 1.8% (SO3), 0.9% Ignition loss,
and 0.8% free CaO.
This kind of cement has the highest % composition of C2S , thus making it highly
sulfate resistant .
Used in places nearby to the sea , as it resists sea contact very well .
Preparation of cement is a two step process ...The real game's still on......Keep logged into this site for an overview into it soon ;)
