What Is Cement?
Cement is a binder of construction materials; due to its adhesion and cohesion properties, it provides excellent bond strength to the concrete. Cement is mixed with filler materials like sand, and aggregates that provide sufficient rigidity to the structure.
When cement, fine aggregates, and coarse aggregates are mixed with sufficient water, concrete is formed. Various types of cement such as Ordinary portland cement(OPC), portland pozzolana cement(PPC), Rapid hardening cement, etc are available in the market.
In this article, we will discuss 16 different types of cement and their uses in construction work.
Chemical Composition Of Cement:
- Lime (CaO) – 60 to 67 %
- Silica (SiO2) – 17 to 25 %
- Alumina (Al2O3) – 3 to 8 %
- Magnesia (MgO) – 0.1 to 4 %
- Iron Oxide – 0.5 to 6 %
- Sulphur Trioxide (SO3) – 1 to 3 %
- Alkalies ( Soda and Potash) – 0.5 to 1%
Types Of Cement:
Cement can be divided into two categories
a. Hydraulic cement.
b. Non-hydraulic cement.
a. Hydraulic Cement:
Hydraulic cement is a type of cement that not only harden on reacting with water but also form water-resisting products. Cement on reacting with water commences the hydration reaction. Hydration reaction is the process by which the cement mixture gains its strength by forming various compounds with the evolution of heat.
The products of the hydration reaction like the Calcium Silicate Hydrate (CSH) gel, Calcium hydroxide, and ettringite are not only insoluble in water but also are quite strong in water.
Hydraulic cement can successfully be used inside the water for marine structures, water retaining structures, etc.. There are 16 types of hydraulic cement that have been discussed in this article below.
1. Ordinary Portland cement(OPC),
2. Portland Pozzolana cement(PPC),
3. Rapid hardening cement,
4. Extra Rapid hardening cement,
5. Quick setting cement,
6. Sulphate resisting cement,
7. Low heat cement,
8. Oil well cement,
9. Blast furnace slag cement,
10. Expansive cement,
11. Hydrophobic cement,
12. Masonry cement,
13. Air entraining cement,
14. High alumina cement,
15. White cement,
16. Coloured cement,
b. Non-Hydraulic Cement:
Non-Hydraulic cement is derived from the calcination of gypsum and calcium carbonates. Slaked lime is an example of non-hydraulic cement. These cement don’t harden on reacting with water but by coming in contact with carbon dioxide. Carbon dioxide commences the carbonation reaction which sets the cement.
This type of cement cannot be used with water or underwater. This type of cement is weaker than the hydraulic cement and is not widely used because of the long setting periods.
Applications:
Rarely used as mortars for brick or stone masonry.
Types of Hydraulic Cement:
1. Ordinary Portland Cement (OPC):
Ordinary Portland cement(OPC) is made by pulverising calcium silicate clinkers, calcium sulphates, and limestones at high temperatures. OPC consists of key elements called Bogue’s compounds which are responsible for the strength gain and hardening of the cement. The names of the Bogue’s compounds and their composition in the ordinary Portland cement are as follows:
- Tri-Calcium Silicate – 25% to 50%
- Di-Calcium Silicate – 20% to 45%
- Tri-Calcium Aluminate – 5% – 12%
- Tetra-Calcium Alumino Ferrite 6% – 12%
Tri-Calcium Silicate:
This is responsible for the early gaining of the strength of the cement and thus produces more heat due to the accelerated hydration reaction.
It has less resistance to chemical attacks.
Di-Calcium Silicate:
It is responsible for the strength gain in the later stages. It has high resistance to chemical attacks.
Tri-Calcium Aluminate:
This is responsible for the rapid setting action of the cement It evolves high heat due to hydration reaction.
Tetra-Calcium Alumino Ferrite:
It is responsible for the rapid setting action of the cement It evolves moderate heat due to hydration reaction.
OPC is a basic type of cement consisting of the Bogue’s components in the above proportions to gain the desired strength in 28 days. The different grades of Ordinary Portland cement are 33 grade, 43 grade, and 53 grade. The OPC 33 grade of cement will gain 33 MPa in 28 days and so on. The OPC can be stored for 3 months in a cool and dry place.
Application:
OPC is the most commonly used cement type in structures. It can be used in
- i) Structural components like beams, columns, slabs, footings, etc
- ii) Plastering,
- iii) Tanks,
- iv) Culverts,
- v) Massive structures and mass construction.
2. Portland Pozzolana Cement (PPC):
This type of cement is made of the Ordinary Portland Cement clinkers, gypsum and fly ash. Fly ash is a waste product from the thermal power plants. The advantages of using fly ash in the cement not only reduce air pollution but also increases the strength of the cement.
Flyash decreases the rate of strength gain in the early days. But the strength of the cement increases in the later stages. The fly ash reacts with the Calcium Hydroxide in the hydration products to form Calcium Silicate Gel (CSH gel) which is responsible for the strength of the cement. The PPC cement can be stored for 3 months in a cool and dry place.
Advantages Of PPC:
- i) Low heat of hydration.
- ii) Increases fineness.
- iii) Decreases permeability.
- iv) Increased durability.
- v) Resistance to chemical attack.
- vi) Resistance to corrosion of reinforcements.
Application:
- i) All normal construction activities.
- ii) Massive construction.
- iii) Water retaining structures.
- iv) Marine and hydraulic structures.
- v) Foundations.
3. Rapid hardening Cement:
Rapid hardening cement (RHC) also called High early strength portland cement. concrete has high percentages of Tricalcium Silicate (C3S) and low percentages of Di Calcium Silicate(C2S).
This composition accelerates the hydration reaction leading to the rapid strength gain of the cement. Due to the increased lime content, 70% of the stipulated strength (7 days strength of OPC) can be gained in three days.
The strength attained by rapid hardening cement in 7 days is almost same as 28 days strength of opc. Due to the accelerated hydration reaction, the evolution of heat is high. Necessary actions must be taken to reduce the shrinkage cracks that may occur due to the high heat of hydration evolved.
Advantages Of Rapid hardening Cement:
- i) It attains high strength in very short time.
- ii) Formwork can be removed earlier and reused in other construction works which saves the cost of formwork.
- iii) Protects concrete from freezing.
- iv) Allows faster completion of the project.
Applications:
- i) Precast constructions.
- ii) Road construction and repair works.
- iii) Cold weather concreting (Due to the high heat of evolution).
4. Extra Rapid hardening cement (ERHC):
Extra Rapid hardening cement is an enhanced version of the Rapid hardening cement. In addition to the composition of RHC, calcium chloride of weight not less than 2% is added to the cement. This accelerates the hydration process.
Some Extra Rapid hardening cement can gain as much as 15 Mpa and 25 MPa in 8 hours and 24 hours respectively. The concreting should be done within 20 minutes of mixing with water to prevent setting. This types of cement can be stored for a period of 1 month only after which it may lose its properties and become unusable.
Application:
- i) Cold weather concreting.
- ii) Precast construction.
5. Quick Setting Cement:
Quick setting cement as the name suggests will have a quicker setting action. The setting action of this cement starts within 5 minutes as it becomes stone-hard in less than an hour. The natural retarder that slows the setting process in the cement is the gypsum.
The quantity of gypsum present in the cement is restricted to not more than 3% and accelerators like aluminium sulphate are added to speed up the setting action. Due to the increased sulphate content, the risk of sulphate attack is elevated. It is also very expensive and demands great care in placing the concrete.
Advantages Of Quick Setting Cement:
- i) It has less setting time than ordinary cement.
- ii) It has high resistance towards the water.
- iii) It requires less amount of water during hydration.
Application:
- i) Underwater constructions.
- ii) Rainy regions.
- iii) Repair works.
6. Sulphate Resisting Cement:
The aluminates present in Bogue’s compounds react with the sulphates in the soil or water to form high volume products like calcium sulphate and Calcium Sulpho Aluminate. Due to the amplified volume, the internal pressure increases and as a result cracks are formed. This is called Sulphate attack.
In this type of cement, the problem causing Bogue’s compounds such as Tricalcium Aluminate(C3A) and Tetra-Calcium Alumino Ferrite(C4AF) are restricted to 5% and 6% to 12% respectively.
Advantages Of Sulphate Resisting Cement:
This cement has excellent resistance to sulphate attack than ordinary cement.
Applications:
This type of cement is used in
- i) Sulphate bearing soil or water.
- ii) Foundations.
- iii) Drainage pipes.
7. Low Heat Cement:
Low heat cement produces low heat of hydration during the strengthening process. Excess heat of hydration may trigger pre-mature shrinkage cracks. The heat evolution can be controlled by reducing the heat producing Bogue’s compounds.
The tricalcium silicate (C3S) and tricalcium Aluminate (C3A) are reduced and Dicalcium Silicate (C2S) is increased to achieve sufficient strength with low heat evolution. Due to the retarded hydration process, the early strength gain is less but the required strength is gained at the later stages.
Advantages Of Low Heat Cement:
- i) This cement has slower rate of heat of hydration.
- ii) It has greater resistance to cracking.
- iii) It also offers greater sulphate resistance due to decreased amount of C3A ( Tri-calcium aluminates).
Application:
This cement is used for
- i) Mass construction (Dams, massive retaining walls, bridge abutments etc.)
- ii) Hot weather concreting.
8. Oil Well Cement:
Oil well cement is used in the process of oil well drilling. During the drilling process, steel casings are inserted inside the holes. The surrounding earth around the steel casings may not be continuous and stiff.
Any discrepancies in the surrounding soil will increase the risk of escaping of the invaluable gases or oil. In order to prevent it, the oil well cement is used to reinforce the earth surrounding the drill hole.
This cement should be able to flow to greater depths and withstand a temperature of minimum 175 degree centigrade and a pressure of at least 3000 kg/cm3. This can be achieved by adding retarders like starch and cellulose to the cement.
Advantages Of Oil Well Cement:
- i) The setting time is convenient allows concrete in very high temperature.
- ii) It has great retardar reaction.
- iii) Protects the casing well from corrosion.
Application:
This cement is used for oil well drilling.
9. Blast Furnace Slag Cement:
Blast Furnace slag cement is made up of the Ordinary Portland Cement clinkers, gypsum and Ground Granulated Blast Furnace Slag (GGBS) added in certain proportions.
The GGBS is a waste product from the steel manufacturing industry. Using the Ground Granulated Blast Furnace Slag will not only reduce the pollution levels but also has the following
Advantages:
- i) Low heat of hydration.
- ii) Low permeability.
- iii) Increased resistance to chemical attack.
- iv) Increased durability.
Applications:
This types of cement is used in
- i) All normal construction activities.
- ii) Massive construction.
- iii) Water retaining structures.
- iv) Marine and hydraulic structures.
- v) Foundations.
10. Expansive Cement:
Expansive cement is made up of Ordinary Portland Cement clinkers, expanding agents, and stabilising agents. Cement, contracts on hardening which may cause non-structural cracks in the structure.
This contraction can be avoided by using expanding agents like sulpho aluminate clinkers. Expanding agents must always be accompanied by stabilising agents like calcium chloride or pozzolana to prevent over expansion.
There are two types of expansive cement namely the shrinkage compensating expansive cement and self-stressing expansive cement. Due to the presence of sulphates, the risk of sulphate attack increases.
Advantages Of Expansive Cement:
- i) It reduces shrinkage cracks in structure.
- ii) It excludes the use of waterproofing treatment of roof slab.
Application:
- i) Mass construction.
- ii) Roof slab
- iii) Canal and tunnel lining.
- iv) Concrete parchment.
- v) Repairing works of concrete structures.
11. Hydrophobic Cement:
Hydrophobic cement is made by grinding Ordinary Portland Cement clinkers, gypsum, and water-repelling substances like stearic acid and oleic acid in the manufacturing process itself. These repellents form a film around the materials of the concrete and produce a water-repelling mix.
For increased efficiency, vigorous mixing of the aggregate is recommended to break the film and initiate the hydration reaction. This cement can be stored for longer periods even in cold weather regions because of the water-repelling film around the cement particles.
Advantages:
- i) Highly resistant to water penetration.
- ii) Resistant to corrosive action of acids and alkalies present in industrial water.
Application:
This types of cement is used in
- i) Water retaining structures like dams, tanks, reservoirs, retaining walls, swimming pools, bridge piers etc.
- ii) In High rainfall regions.
12. Masonry Cement:
Masonry cement is made up of Ordinary Portland Cement clinkers, gypsum, limestone and air-entraining agents. Based on the requirements, water-repellent additives may also be added to the cement.
Masonry cements are used for preparing the mortar for building the masonry structures – stone masonry or brick masonry. It is not widely used.
13. Air Entraining Cement:
Air entraining cement is made up of Ordinary Portland Cement clinkers, gypsum, and air entraining agents. The need for air entraining agents is prominent in cold weather regions that are vulnerable to freeze thaw cycles.
The liquid water penetrating into the cement structure under freezing temperatures will turn into solid ice. The volume occupied by the solid ice is greater than that of the liquid water thus increasing the internal pressure.
As a result, cracks will be formed to release the pressure. This is called the freeze thaw cycle. This can be avoided by using air entraining agents like wood resins, hydrogen peroxide, aluminium powder, sulphonic acid, etc.
These air entraining agents will form artificial air pockets inside the mix. Air entraining admixtures can also be added to ordinary cement to achieve the same results.
These air pockets can make up to the extra space needed by the formation of ice. This increases the durability of the structure but obviously the air pockets will reduce the strength of the concrete. Air bubbles should not be more than 3 to 4 % than the volume of the concrete.
Advantages Of Air Entraining Cement:
- i) Resistant to frost action and immune to surface scaling.
- ii) Concrete made with this cement is more plastic.
- iii) Increased workability.
- iv) Reduced segregation, shrinkage, bleeding and laitance.
Application:
This types of cement is used in cold weather regions.
14. High Alumina Cement:
High Alumina cement is obtained by adding alumina (at least 32% to 80%) to the Ordinary Portland Cement clinkers. This cement is also known as the calcium aluminate cement.
This is made by pulverising calcium aluminate clinkers alone. Unlike other hydraulic cement, high alumina cement does not have Tricalcium Sulphate and Dicalcium sulphate as the base material.
Advantages:
- i) High early strength.
- ii) Ability to harden even under low temperature conditions.
- iii) High durability.
- iv) Excellent resistance to fire.
- v) Early removal of formwork.
- vi) High resistance to sulphate attack, acid water, sea water etc.
However, the main drawback is the reduction of strength with time.
Application:
This type of cement can be used in
- i) Underwater construction.
- ii) Construction near sea shore.
- iii) Sealing rocks or concreting against internal water flow.
15. White Cement:
The grey colour of the cement is caused by the presence of Iron oxide. By reducing the amount of Iron oxide in the cement to less than 1%, white cement can be obtained.
White cement is made by using high purity limestone and china clay both of which are known to have low iron content. It is expensive than ordinary cement. The fineness of white cement is greater than that of normal cement.
Application:
This types of cement is used for
- i) Fixing tiles, marbles.
- ii) Floor finish.
- iii) Ornamental works.
- iv) Stucco plastering.
- v) Precast industries.
- vii) Pavers due to their high reflectiveness.
- vii) Aerodrome markings.
16. Coloured Cement:
Various colours can be imparted to the cement by adding mineral pigments. For example, adding cobalt induces blue colour, chromium gives green colour and various proportions of iron oxide give grey, brown and red colour.
Application:
This types of cement is used only for Ornamental purposes.
Frequently Asked Questions:
1. What are the 5 types of cement?
The common 5 types of cement are ordinary portland cement (OPC), Portland pozzolana cement (PPC), Rapid hardening cement, Low heat cement and Sulphate resisting cement.
2. How many types of cement are there?
Cement are mainly two types, hydraulic cement and non-hydraulic cement. There are 16 types of Hydraulic cement available in the market which are as follows:
- Ordinary Portland cement(OPC),
- Portland Pozzolana cement(PPC),
- Rapid hardening cement,
- Extra Rapid hardening cement,
- Quick setting cement,
- Sulphate resisting cement,
- Low heat cement,
- Oil well cement,
- Blast furnace slag cement,
- Expansive cement, Hydrophobic cement,
- Masonry cement,
- Air entraining cement,
- High alumina cement,
- White cement,
- Coloured cement,
3. Which cement is best for house construction?
OPC and PPC are the best types of cement for house construction.
4. What is Type 2 cement used for?
Type II cement is used in drainage structures where sulphate concentrations in groundwaters are higher than normal but not unusually severe.
5. Which type of cement is best?
OPC 43, OPC 53 and PPC.
6. What is the full form of PPC cement?
The full form of PPC is Portland pozzolana cement.
7. Which is the No 1 cement in India?
UltraTech Cement Ltd. is the largest manufacturer of grey cement, Ready Mix Concrete & white cement in India.
8. How many types of cement in India?
OPC 33, 43 and 53 grade, Portland pozzolana cement, Portland Slag Cement (PSC) Rapid Hardening Cement Sulphate Resisting Portland Cement (SRC) Low Heat Portland Cement Hydrophobic Portland Cement, White Cement and coloured cement.
9. Which cement is costly OPC or PPC?
OPC is little bit costly compared to PPC.
10. Which is best cement for plastering?
OPC 43 and OPC 53 are best cement types for plastering work.
11. Which cement is best for columns?
OPC 53 is best for construction of columns, footings, beams and slab.
Also Read
Types Of Slabs Used In Construction
Types Of Bricks And Their Uses In Construction
Gypsum Plaster – Advantages and Disadvantages
Which Cement Is Better – OPC Or PPC?
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