Cement is the most used building material. Learn about the 13 types of cements. Furthermore, you will also learn about the chemical composition and how cement gains strength (Bogue's Compounds). By the end, you will get a snapshot of the field and lab tests to ascertain the quality of cement.

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Civilverse Admin 4 July 2020
Cement-Types, Composition & QC
civilverse.org/cement-types-composition-bogues-compounds-qc
Table of Content for Cement-
Introduction
Types
Composition of Cement
Bogue’s Compounds
Site Testing
Lab Testing
The property of hardening when mixed with water makes the cement a popular
construction material. The presently used form of cement started developing after
William Aspdin accidentally discovered the calcium silicates. On hardening, it appeared
similar to a stone found in Isle of Portland, England. Thus, the name Portland Cement
came into existence. OPC is the most basic form of cement. The properties of cement are
strength, setting time, soundness, etc. The properties can be altered as desired by
changing the percentage composition of the limestone, alumina, and silica.
The cement is used with sand, and aggregate to make the concrete. On mixing water to
the above-said mixture, concrete is produced. The properties of concrete can be modified
as required by changing the proportion of its elements. Further, admixtures can also be
used for controlling the properties of the mix.
Types of Cement-

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The properties of various types of cement differ from each other.
1. Ordinary Portland Cement (OPC)- It is prepared by calcining limestone with
silica and alumina.
2. Pozzolana Portland Cement (PPC)- It is prepared by grinding a 10-15% fly-ash
with the OPC.
3. Rapid Hardening- It is used where early strength of concrete is required. It is
finer than the OPC.
4. Extra Rapid Hardening – It is prepared by adding accelerators such as calcium
carbide in a small amount. The rate of gain of strength is higher.
5. Quick Setting- It is used where a quick setting is required. It has a lower setting
time than OPC.
6. Portland Slag- It is prepared by grinding OPC with the slag.
7. Sulphate Resisting- It is used for the concrete that is to be placed in contact with
sulphate containing aggressive soil.
8. Low Heat- It is used for mass-concreting works such as dams etc. It generates
lesser heat of hydration. The rate of gain of strength is also lower.
9. High Alumina- It is made up of calcium aluminate unlike the calcium silicate as in
OPC.
10. Hydrophobic- It is prepared by grinding OPC clinker with the film-forming
substance. It is used when cement is to be stored in high humidity areas.
11. White- It has very small or no percentage of iron oxide.
12. Low Alkali- It has alkali content lesser than 0.6%. It is used where aggregate has
silica avoid the alkali-aggregate reaction.
13. Coloured- It is prepared by grinding 5-10% of suitable pigments with white or grey
cement.
Composition of Cement-
The cement composition can be broadly classified into two heads-
1. Calcareous- This term refers to the Calcium. This head is represented by the lime.
2. Argillaceous- This term refers to the Alumina. This head is represented by the
clay.
The cement composition should also satisfy the following criteria-
The chemical composition is as follows-

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Chemical Composition of Cement
Lime- It imparts strength and soundness. The excess of lime makes the cement unsound,
increases expansion, and disintegration. The deficiency of lime leads to lower strength
and quick setting.
Silica- It imparts strength. The excess of silica increases the strength and setting time.
Alumina- It imparts strength. The excess of the alumina increases the strength and
setting time. It also aids in reducing the clinkerisation temperature.
Gypsum- It is present in the form of calcium sulphate. It is added to the clinker when
grinding to increase the initial setting time.
Iron Oxide- It imparts strength and hardness to the cement. The grey colour is due to
iron oxide.
Magnesia- It imparts strength and yellowish tint. The excess of magnesia makes the
cement unsound.
Sulphur- It imparts soundness.
Alkalis- Alkalis cause efflorescence and staining on the finished surface after hydration.
They cause white-grey spots on reacting with water.
Bogue’s Compounds-
The calcareous and argillaceous constituent fuse together to make four types of
compounds known as Bogue’s Compounds. These compounds govern the properties of
the cement. The silicate compounds formed are mainly responsible for the strength. The
alumina and iron compounds contribute little to the strength development.
Upon hydration, the silicate compounds form an amorphous gel of calcium silicate
hydrate and calcium hydroxide. This gel is called C-S-H gel. The C-S-H gel binds the
cement particles together and provides strength.

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Bogue’s Compounds
Tricalcium Aluminate, C A- It is formed within 24-hours of the hydration. It gives
maximum heat of hydration.
Tetra Calcium Alumino Ferrite, C AF- It is formed within 24-hours of the
hydration. The heat of hydration is comparatively higher in the initial stage of hydration
and decreases substantially.
Tricalcium Silicate, C A- It is formed till a week of the hydration. It provides strength
in the first week after the hydration.
Dicalcium Silicate- It is formed very slowly and the strength developed due to it may
take a year. Thus, it can be said that C2S responsible for the progressive strength in the
later stages.
Order of Heat of Hydration- C A > C S > C AF > C S
Quality Control–
The testing of cement can be conducted on site and as well as in the laboratory.
Classification of Tests for Cement
Site Testing-
1. It should not be older than three months.
2. The colour should be uniform.
3. The lumps should not be present.
4. On inserting a hand inside the cement bag, it should feel cold.
5. On throwing a hand full of cement into the bucket of water, it should sink.
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Lab Testing-
1. Fineness Test- By Sieve & air permeability test.
2. Standard Consistency Test- By Vicat apparatus.
3. Setting Time Test- By Vicat apparatus
4. Soundness Test- By Le-Chatelier apparatus
5. Strength Test- By compression testing machine
6. Chemical Composition Test
For more on Bogue’s Compounds-
http://shodhganga.inflibnet.ac.in/jspui/bitstream/10603/142503/9/09_chapter%203.p
df
Done with cement? How about reading article on concrete sand or bricks?
Happy Engineering!