6 Types of Cement and Their Applications in Architecture

Cement is one of the most widely used building materials in the construction industry. It is usually mixed with water, aggregate and additives to either make concrete or mortar.

The ratio of water and cement in a mixture determines its quality and strength. Once applied, the mixture is left to harden or 'cure' for a certain period of time in particular conditions.

Types Of Cement

• Ordinary Portland Cement (OPC)
• Portland Pozzolana Cement (PPC)
• Rapid Hardening Cement
• Sulphate Resisting Portland Cement
• Blast Furnace Slag Cement
• High Alumina Cement

1. Ordinary Portland Cement (OPC)

Ordinary Portland cement is the most commonly used cement for making concrete due to its low cost and easy manufacturing.

- Raw Materials

• Silicates of alumina or more commonly known as clay
• Limestone
• Gypsum

- Manufacturing Process

• Limestone and clay is mixed in the ratio of 2:1 
• This mix is then ground evenly in mills either in a dry powder or slurry state.
• This mixture is burnt in a rotary kiln at 1400 degrees Celsius.
• It is taken out and cooled before adding gypsum.
• This final mixture is once again grounded according to requirements.

- Advantages

• It is resistant to cracks and shrinking.
• OPC is cheap and easy to manufacture and use.
• Ordinary portland cement cures faster than many other types of cement.

- Disadvantages

• OPC is not very resistant to chemical attacks.
• It is less fine, making it highly permeable and consequently, less durable.

2. Portland Pozzolana Cement (PPC)

In ancient Rome, Pozzolana, volcanic ash was used to make cement. This material is mixed with OPC to make Portland Pozzolana Cement or PPC.

- Raw Materials

• Pozzolanic materials
• Limestone
• Clay
• Gypsum

- Manufacturing Process

• Limestone and clay are ground and heated in a rotary kiln (same as OPC manufacturing)
• The mixture is then cooled by a rotary cooler.
• Gypsum and pozzolanic materials are added to the mixture.
• Along with the additions, the final mixture is grounded again.

- Advantages

• Highly impermeable and hence used for building hydraulic and marine structures.
• Used in harsh conditions.
• PPC had a better finish, making it fit for making ornamental structures.

- Disadvantages

• Difficult to handle than OPC
• Not as easy to use as OPC. Handling should be done carefully.
• Initially has less strength and gradually cures over time.

3. Rapid Hardening Cement

Rapid hardening cement is a type of cement which cures and achieves hardening in a very short amount of time.

- Raw Materials

• Limestone
• Shale
• Gypsum

- Manufacturing Process

• Rapid hardening cement is made using the dry cement process.
• Limestone and shale is ground finely and heated in a kiln to make clinker.
• Gypsum is added to the clinker and ground evenly again.

- Advantages

• Very high strength is achieved in less time.
• Can be used in places where formwork needs to be removed immediately or used elsewhere.
• Used on pavements or other places where construction needs to be completed quickly.
• This is a good choice for construction in colder climates.
• Very durable and resistant to sulphate attacks.

- Disadvantages

• RHC should not be used for building hydraulic or marine structures.
• It is expensive compared to other cements.
• Since the setting time is less, it releases a large amount of heat in a short time.

4. Sulphate Resisting Portland Cement

Sulphate Resisting Cement is a type of Portland cement where the amount of sulphate salts is less than 5 percent. This reduction makes it resistant to sulphate.

- Raw Materials

• Limestone
• Shale
• Iron oxide

- Manufacturing Process

• Limestone, shale and iron oxide is ground finely to form cement clinker using the dry process and then heated in a kiln.
• A small amount of gypsum is added to the clinker and ground again.

- Advantages

• SRPC has high durability even in harsh conditions.
• It is highly resistant to sulphate attacks.
• It emits low amounts of heat during curing, in comparison to other types of cement.
• It is very useful in constructing underground or deep structures.

- Disadvantages

• Sulphate-resistant cement is expensive in comparison.
• It is not suitable for areas with higher chlorine concentration, as it is not resistant to it.

5. Blast Furnace Slag Cement

Blast furnace slag is obtained as a byproduct of steel manufacturing. This slag is granulated and mixed with OPC to produce blast furnace slag cement.

- Raw Materials

• Slag from steel manufacturing
• Limestone
• Clay
• Gypsum

- Manufacturing Process

• The slag obtained from steel manufacturing is cooled until mon-reactive crystals are formed.
• This is mixed with the cement clinker obtained from mixing ground limestone and clay and then heating in a kiln.
• The mixture is grounded once more after the addition of slag.

- Advantages

• Strength gained over time is higher than normally used concrete.
• Resistant to both sulphate and chloride attacks.
• Impermeability is achieved as finely ground slag fills pores.
• Since the setting time is more, heat emitted during hydration is less.
• Production cost is even lesser than OPC.
• This cement has high durability.

- Disadvantages

• Blast furnace slag cement cannot be used in RCC construction as the initial strength is very less.
• It's hard to make changes and repair since the setting time is high.

6. High Alumina Cement

High alumina cement is manufactured by grinding alumina with lime using the fusing or sinistering method.

- Raw Materials

• Lime
• Bauxite

- Manufacturing Process

• Bauxite and lime are grinded into small fragments.
• The mixture is then heated in a kiln upto 1600 degrees Celsius.
• This clinker is then cooled in a rotary kiln.
• Finally, the mixture is grounded finely again.

- Advantages

• It is used in constructing hydraulic and marine structures.
• It is fire resistant and can withstand high temperatures.
• It has good resistance to chemicals.
• It has high compressive strength.

- Disadvantages

• The particles are extremely fine and hence, difficult to handle and also unsafe.
• The cost of manufacturing and construction is higher in comparison.

Cement, in today's world, is widely used for various applications. Although it is not a very environmentally friendly material, it offers a lot of choice and flexibility to the users.

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