Everyone knows cement and even some of you might have purchase also, but do you want to know in detail like how cement invented, types, important, etc. which makes it’s an important building material then you should read this complete blog.
Cement is a fine powder, grey in color form by burning a proportioned mixture of different materials for binding other construction materials together.
So various RCC structure likes beams, columns, slabs, etc. are constructed by using this material to prepare concrete which is used along with steel bars.
It is also utilized in bridges, water tanks, chimneys, nuclear power plants, roads, domes, etc.
Let us understand the following important topic
- Invention And History
- Types of Cement
- Various Properties
- Setting Time
- Comparison Cement v/s Lime
Invention And History
In 1824, Joseph Aspdin a British stone mason gives the introduction and the name of the currently used Portland cement.
He was trying to fire the mix of finely ground limestone and clay with water, after a while, he noticed that the mixture was set and it gets hard. He found that it was cement which bonded and hardens the mixture
In England, there are many mines of Portland stone from which lime and stone are extracted and Portland cement color is similar to it so he gave this name.
The first engineering structure made from this was Thames River Tunnel in1828
The commercial production of it is firstly started in 1852 in Germany.
In the year 1872 America also started making Portland cement.
Fedrick Ranson in 1886, firstly experimented with the use of Rotary Kiln for the production of this material. The water/cement ratio for this is given by Duff Abraham in 1919.
Le chatleir in 1887 proved that Tricalcium silicate (C3S) is one of the important elements in the clinker.
In the past in during the 19th century there was only one type of cement, but currently it is more than 10.
In India the first Portland cement production started in the year 1913.
It is is also known as hydraulic cement.
|Alumina||Helps to set quickly|
|Iron Oxide||Gives color, hardness, strength|
|Magnesia||For hardness and color|
|Gypsum||Increase time for initial setting|
Types of Cement
- Ordinary Portland (OPC)
- Rapid Hardening
- Quick Setting
- Pozzuolana Portland (PPC)
- Low Heat
- Blast furnace
- White cement
- Sulphate Resisting
- Colored cement
- Air entraining
- High Alumina
Like this material do you want to know about concrete also? Know more about concrete here.
- By initial and final setting time
- Through the size of particles
- Consistency and Soundness
- Compressive Strength and
- Tensile strength.
Fineness: The finest is the size; the best is the quality, as it gives early strength and duration of hardening.
Soundness: It’s a property to generate non-disintegrating and strong mass during the setting.
The setting is different from the hardening of it. As setting time varies for every, some sets quickly and some take time.
So the setting of it means the conversion of a plastic paste of cement and water to a non-plastic and rigid mass.
Initial setting time of it shall not be less than 30 to 60 minutes and
Final setting time shall not be more than 10 hours.
Eventually the Compressive strength is measured on 7.06 cm cube of mortar
(1 cement 3 sand) [CM (1:3)] on a standard Universal Testing machine
(UTM). Total 9 cubes are made: 3 to be tested after 3 days, 3 after 7
days and 3 after 28 days.
Thus the average of three values in each test is taken as the compressive strength of cement after so many days.
Likewise, for more such in-depth knowledge you should refer IS 456 (2000): Plain and Reinforced Concrete
In the tensile strength testing machine, tensile strength is measured by standard briquettes of CM (1:3) which is for 24 hours kept in moist weather, and they are taken for testing after submerged in water.
So a total of 18 briquettes are made: 6 to be tested after 3 days, 6 after 7 days, and 6 after 28 days. The Average of six values in each test is taken as the tensile strength of that materials after so many days.
|For OPC||after 3 days||after 7 days|
|Compressive strength||≥ 115 kg/cm2||≥ 175 kg/cm2|
|Tensile strength||≥ 20 kg/cm2||≥ 35 kg/cm2|
So the quality of this material depends upon components present in it, especially
the lime, silica, iron and alumina. Likewise IS specification (IS: 269-1973) guides for the chemical composition of ordinary Portland and rapid hardening.
- It should not possess an excess of alumina as it may reduce the strength of the materials.
- They should not contain the amount of alkalis oxide (K2O) and (Na2O) more than one percentage.
- More than 5 % Magnesium oxide (MgO) should not be there, as it wills results in cracks at the time of the hardening of mortar or concrete.
- An excess lime should not possess in it, otherwise it makes it unsound and cause the material to expand and disintegrate.
- If lime level is at the point of deficiency, the strength of it is decreased and it causes in result to set this material quickly.
- There is should not be more than the excess amount of silica, otherwise, the setting period time is longer than usual
- As soundness is important so to make it sound a very small amount of sulfur should be added.
- It should be free from lumps
- They should be stored in closed rooms. A platform or stage should be made to store bags to avoid the direct contact of water and moisture.
- It should be covered properly especially during rainy seasons.
- When touching with hand the temperature of it we feel should be cool
- It should be in the form of fine powder while checking with the first finger and thumb.
Comparison Of Cement v/s Lime
|It is very strong||Lime is comparatively weak|
|This has no flexibility||lime is more elastic|
|It has more durability||It has less durability|
|This is used in high traffic areas||It’s used in low traffic areas|
|It is less expensive||Lime is more expensive|
• It plays a vital role in binding the materials with each other
• As it combines with particles of and to form mortar. The mortar prepared from it helps in filling the joints of bricks and stones in wall masonry.
• The Settled and cured concrete acts as a solid member like a hard stone in the desire shape and size of various building components.
•Generally paste makes plaster smooth work on various building components to cover and protect them.
• At various surfaces may be rough or not rough, work gets easier and economical.
In 1824, Joseph Aspdin a British stone mason discovered this material.
It is the weight of water to the weight of cement in concrete mix.
If you are in direct exposure to it regularly for a long time without any prevention will cause damages to various body parts.
Ordinary Portland cement (OPC) is used with the bricks.