Ordinary portland cement (opc) & Rapid hardening cement

Presented By : : Prajapati Ghanshyam
Ordinary Portland Cement (OPC)
&
Rapid Hardening Cement
Concrete Technology

Content
 Definition of Cement & its types
 Basic composition of ordinary portland cement
 Production & Manufacturing Process
 Uses of OPC
 Grades of OPC
 Rapid Hardening Portland Cement

Cement & its types
 Definition : “ It is defined as the bonding material
having cohesive and adhesive properties which
makes it capable to unite the different construction
materials and form the compacted assembly.”

 Types of Cement :
 Ordinary Portland Cement
 Rapid Hardening Cement
 Sulphate Resisting Cement
 Quick Setting Cement
 Super Sulphated Cement
 Low Heat Cement
 Pozzolona Portland Cement
 Coloured Cement
 Hydrophobic Cement
 Expansive Cement

Ordinary Portland Cement
 Ordinary Portland Cement is one of the most widely used
type of Portland Cement.
 The name portland cement was given by Joseph Aspdin in
1824 due to its similarity in colour and its quality when it
hardens like Portland stone.
 Portland stone is white grey limestone in island of Portland,
Dorset.
 Composition of OPC : The chief chemical components of
ordinary portland cement:
1. Calcium 3. Alumina
2. Silica 4. Iron

Basic composition of OPC
Contents %
CaO 60-67
SiO2 17-25
Al2O3 3-8
Fe2O3 0.5-6.0
MgO 0.5-4.0
Alkalis 0.3-1.2
SO3 2.0-3.5
The chief compound which usually form
in process of mixing :

Contribution of Compounds to Strength

Production & Manufacturing Process
 Manufacturing
Raw Materials
1. Calcareous (material having content of lime)
2. Argillaceous (material having content of silica & alumina)
3. Gypsum
Process
Cement is usually manufactured by two process:
1. Wet process
2. Dry process
These two process differ in operation but fundamental of
both these process are same.

 There are five stages in manufacturing of cement by wet
process:
I. Crushing and grinding of raw materials
II. Mixing the material in proportion
III. Heating the prepared mixture in rotary kiln
IV. Grinding the heated product known as Clinker
V. Mixing and grinding of cement clinker with gypsum

 Crushing And Grinding:
In this phase, soft raw materials are first crushed into suitable
size. This is done usually in cylindrical balls or tube mills
containing the charge of steel balls.
 Mixing the material:
In this part, the powdered limestone is mixed with the clay
paste in proper proportion (75%=limestone; clay=25%)
The mixture is then grounded and made homogeneous by
mean of compressed gas.
The resulting material is known as “Slurry” having 35-40%
water.

 Heating the slurry in rotary kiln:
Slurry is then introduced in rotary kiln with the help of
conveyor. The rotary kiln consists of large cylinders 8 to 15 feet
in diameter & height of 300-500 feet.
Kiln rotates at the rate of 1-2 revolution per minute. In rotary
kiln, slurry passed through different zones of temperature.
This whole process in kiln usually covers 2 to 3 hours.

Different temperature zones are as under:
i. Preheating Zone : Temperature is kept upto 500 degree
celsius.
ii. Decomposition Zone : Temperature is raised upto 800 degree
celsius.
iii. Burning Zone : Temperature is maintained upto 1500 degree
celsius.
iv. Cooling Zone : This is last stage where the whole assembly is
cooled upto 150 to 200 degree celsius.

 Clinker Formation:
The product which is obtained from the rotary kiln is known as
the “Cement Clinker”. Clinker is usually in the form of greenish
black or grey colored balls.
 Grinding the clinker with gypsum:
The cement clinker is then air cooled. The required amount of
gypsum (5%) is ground to fine powder and then mixed with
clinker.
 Finally, Cement is packed in bags and then transported to the
required site.

 Production
 The manufacture of OPC is decreasing all over the world in view
of popularity of blended cement on account of lower energy
consumption, environmental pollution, economic and other
technical reasons.
 In India for the year 1998-99 out of the total cement production
i.e., 79 million tons, the production in OPC in 57.00 million tons
i.e., 70%. The production of PPC is 16 million tons i.e., 19% and
slag cement is 8 million tons i.e., 10%.
 In the coming years, the use of OPC may still come down but it
will remain as an important type for general construction.

Uses of OPC
 It is normally used for the reinforced concrete buildings, bridges,
pavements, and where soil condition are normal.
 It is used for general construction purposes where special
properties are not required.
 It has great resistance to cracking and shrinkage but less
resistance to chemical attacks.
 It is also used for most of concrete masonry units.

Grades of Cement
 For engineering purposes, there are many types of cement but in
general, ‘Ordinary Portland Cement’(OPC) which is available in
three grades should be used in house construction.
1. 33 Grade OPC
2. 43 Grade OPC
3. 53 Grade OPC

33 Grade OPC
 It is more suitable cement for masonry and general concrete
works where the members are not taken to very high stresses.

43 Grade OPC
 43 grades of cement are used where high early strength in 1-28
days range is required.

53 Grade OPC
 The strength of 53 grade does not much after 28th day because of
early gain while 33 grade continues to gain strength after 28th
day.

Compressive strength of different brands of cement

Rapid Hardening Portland Cement
 Rapid Hardening Portland Cement (RHPC) is similar to ordinary
cement but with higher tri-calcium silicate (C3S) content and
finer grinding. It gain strength more quickly than OPC, though
the final strength is only slightly higher.
 This type of cement is also called High Early Strength Portland
Cement.
 The one day strength of this cement is equal to the three day
strength of OPC with the same water-cement ratio.

Uses of RHPC
 It is used where formwork has to be removed as early as possible
in order to reuse it.
 It is used where high early strength is required.
 it is generally used for constructing road pavements.
 It is used for cold weather concreting because rapid evolution of
heat during hydration protects the concrete against freezing.

Ordinary portland cement (opc) & Rapid hardening cement

Ordinary portland cement (opc) & Rapid hardening cement

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Ordinary portland cement (opc) & Rapid hardening cement