What is Ordinary Portland Cement?- Chemical Composition, Properties, Uses, Types

Cement is very basic need of any construction work. There are around 19 different types of cements are available in market but Ordinary portland cement is the most widely used type of cement.

Here we will take a look at chemical composition of ordinary portland cement, properties of OPC, uses of OPC, types of OPC, advantages of OPC and disadvantages of OPC.

What is Ordinary Portland Cement?

Cement is a very fine powdered material which on reaction with water forms a paste that has the properties of adhesion and cohesion and on hardening binds aggregates together to form a hard durable compact mass.

Function of cement is first to bind the sand and course aggregate together, to fill the voids between sand and course aggregate and to form compact mass.

History of Ordinary Portland Cement

Modern infrastructure totally based on concrete structures and it would have been impossible to build Burj Khalifa and Jinping-I Dam if cement was not there to prepare concrete. It will worth describing cement as the heart of Modern Infrastructure. But who invented the cement? and how? most of us don’t actually know the history of cement.

Although Joseph Aspdin filed the patent of preparation of ordinary portland cement on 21 October 1824 the basic knowledge every inventor used for preparation of a binding material was investigated by L.J. Vicat who prepared artificial hydraulic lime by calcinating mixture of clay and limestone.

However the name portland refer to natural stone from Portland, England which looked exactly similar to the set cement stone.

As the Use of ordinary portland cement in the construction industry increases rapidly the developed countries set down some standards on the use of cement. Germans set German standard specifications in 1877, British standard specifications set down in 1904 the same year when ASTM standards were specified.

Chemical Composition of Cement

To get all the properties of cement right the oxide composition of cement should be in proper proportions as shown in Table No.1.

The following table shows the chemical composition of cement

Oxide	Formula	Percentage	Average
Lime	CaO	60-65%	63%
Silica	SiO2	17-25%	20%
Alumina	Al2O3	3.0-8.0%	6.3%
Ferrous Oxide	Fe2O3	0.5-6.0%	3.6%
Magnesia	MgO	0.1-4.0%	2.4%
Sulphur Trioxide	SO3	1.3-3.0%	1.5%
Soda and Potash	Na2O + K2O	0.4-1.3%	1.0%

We’ve already explained the Composition of Bogues Compounds with their properties and influence on strength.

Manufacture of Ordinary Portland Cement

The raw materials used for the manufacturing of cement are calcareous materials and argillaceous materials. Calcareous materials are limestone or chalk and argillaceous materials are shale or clay.

The manufacturing process consists of 4 steps or stages those are

1. Grinding of raw materials
2. Mixing of ground materials
3. Burning at high temperature
4. Colling and grinding

Manufacturing can be done by any of the following two methods

1. Wet Process
2. Dry Process

Dry process is considered to be economical as compared to wet process because of less consumption of fuel.

The wet process has the advantages of low excavating cost, low grinding cost, and complete homogeneity in the slurry over the dry process.

Ordinary Portland Cement Properties

Here are the properties of ordinary portland cement

1. Specific Gravity: 3.10 to 3.15
2. Normal Consistency: 29% to 32%
3. Initial Setting Time: 65 min
4. Final Setting Time: 275 min
5. Fineness: 330 kg/sq.m
6. Soundness: 2.5mm
7. Density: 830 to 1600 kg/cubic meter

Types of Ordinary Portland Cement

ASTM classification of Ordinary portland cement is

• Portland Cement ASTM C150
  • Portland Cement ASTM C150

• Portland Cement ASTM C150
  • Type I
  • Type II
  • Type III
  • Type IV
  • Type V
• Blended Cement ASTM C595
  • Type IP
  • Type IS
  • Type IT
  • Type IL
• By Performance Attributes ASTM C1157

Also Read: 17+ Types of Cement used in Construction Works with their Properties and Uses

Tests on Ordinary Portland Cement

Testing of cement is carried out to analyze presence of all the desirable properties in it. Testing of cement is classified under two categories depending on the extent of work and those are

1. Field Tests
2. Laboratory Tests

Laboratory tests are conducted as per IS 4032:1985 and IS 4031(Part 1 to Part 15): 1988-99 and those tests are

1. Fineness Test
2. Standard Consistency Test of Cement
3. Initial and Final Setting Time of Cement
4. Compressive Strength Test on Cement
5. Soundness Test on Cement
6. Heat of Hydration Test on Cement
7. Chemical Composition Test on Cement

Advantages of Ordinary Portland Cement

• Ordinary portland cement is most widely used and therefore easily available in local markets.
• OPC shows good creep resistance and shrinkage resistance.
• High grade cement can reduce the amount of cement required for certain specification of concrete.

Disadvantages of Ordinary Portland Cement

• OPC can not be used where structure is susceptible to sulphates.
• Should not be used in mass concrete constructions.
• Usage in extreme cold and extreme hot environment is not allowed.

Ordinary Portland Cement Uses

• Used in all general concrete constructions where concrete is not exposed to sulphate.
• Used in construction of pavements, bridges, reinforced concrete buildings etc.
• Also used for plastering and decorative masonry works.

FAQs on Ordinary Portland Cement

Ordinary Portland Cement PPT