WHAT ARE THE BASIC MATERIALS REQUIRED TO PRODUCE ORDINARY PORTLAND CEMENT (HISTRY, BASIC COMPONENTS OF CEMENT)

Many people don’t know about the process of production of cement 

How it made?, 

What are the raw materials are required to produce a cement which can be then used for construction purpose

Below is the simple and shot summery of what it actually takes to produce the cement

Raw material used in cement

For the making of cement there are mainly 3 types of materials are required

And they discussed briefly as follows

Calcareous

In this type of materials the major component is CACO3 / calcium carbonate/ lime

Example – chalk, lime stones.

Siliceous

In this type of materials the major component is SIO2 /silicate dioxide

Example – sand stone, clay.

Argillaceous

In this type of materials the major component is FL2O3/alumina

Example – laterite, slate laterite

METHOD OF MAKING CEMENT 

----The cement is obtained by burning these materials together in a definite proportion

---A mixture of calcareous, siliceous, and argillaceous materials to partial fusion at a high

Temperature of 1400O C

---As a result of burning these components a product is obtained called clinkers

---Then these clinkers are cooled rapidly and at the time of grinding of clinkers a retarder like gypsum (p0p) (caso4) is added so that the cement does not set immediately after the addition of water

The amount of gypsum added is about 3 % by the weight of clinkers

History

Cement is first introduced in. 1824 by joseph aspdin. A brick layer (mason) in England. He name tha material as Portland cement because after hardening it resembles in colour to stone query near Portland in England 

Chemical constituents if cement 

The important constituents of ordinary Portland cement are as follows 

constituents	Amount (%)
Lime	60 to 62%
Aluminium oxide	60 to 67%
Silicone oxide	17 to 25%
Alumina (AL2O3)	3 to 8 %
Gypsum (CASO4)	3 to 4 %
Iron and magnesium oxide	0.5 to 4%
And other constituents

Lime provide strength to the cement is it’s the major constituents in the cement

If it is used in excess then it makes the cement unsound

And also causes cement to set quickly

---Silica

Silica provides strength to the cement, it is also an important ingredient but if used in excess it causes the cement to set quickly

---Alumina

Alumina provides quick setting property to cement but if used in excess it weakens the strength of cement

---Calcium sulphate

It helps in increasing the initial setting time of cement. 

---Iron and manganese oxide

These materials are mainly used to provide color to the cement (light grey)

CHEMICAL COMPOUNDS OF CEMENT 

 

These raw materials are converted in to silicate, aluminates and ferrides of calcium

After the process of burning

And the major component found are listed below 
 

Chemical compounds of cement	quantity
Tri calcium silicates (C3S)	25 to 50 %
Di calcium silicate (C2S)	29 to 40 %
Tri calcium aluminates (C3A)	5 TO 11 %
Tri calcium allumino ferride (C4AF)	9 TO 14 %

PROPERTIES OF COMPOUNDS OF CEMENT.

1. Tri calcium silicates

• It hardens rapidly
• Generates more heat of hydration
• It helps in developing early strength
• Less resistance to sulphate attack

2. Di calcium silicate (c2s)

• Hydrates slowly
• Generates less heat
• Hardens slowly and contributes very little for early strength development
• Provides good ultimate strength of concrete and
• More resistance to sulphate attack

3. Tri calcium aluminates (c3a)

• It react fast with wate
• Generates large amount of heat of hydration
• Causes the initial setting of cement

4. Tri calcium allumino ferride (C4AF) 

• Slow in action
• Generates small heat of hydration
• Its nature is poor when it comes to cementing with water

In general C2S and C3S control most of the strength developed property of cement

High percentage of  C3S and low percentage of C2S results in rapid hardening , high early strength with high heat generation and less resistance to chemical reaction