Artificial Materials (Cement)
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Artificial Materials (Cement):-
Definition: it is mixture of calcareous
and argillaceous material burnt in furnace and it becomes a stone like mass
when water is mixed in it.
- It is a fine gray coloured powder used for constructional work.
- It has good binding property.
- It use instead lime due to its superior quality.
- It used to join rigid and solid mass into homogeneous structure.
- It used in building, dams, bridge, road construction.
What is manufacturing process of cement?
- First collecting the raw material used for manufacturing like calcareous material such as lime stone and argillaceous materials such as clay.
- Then it is heated up to 1400-15000C. Due to burning this material converted into big stone called clinker.
- This clinker is cooled and ground to a fine powder with addition of about 2-3% gypsum.
- Then fine powder packed into bags.
Which are the methods of manufacturing of cement?
- Dry process. 2. Wet process.
What is dry process of cement manufacturing?
- Collected raw materials required.
- Each raw material is separately crushed in to 2 inch or smaller pieces, in crusher.
- Crushed materials dried in drier and stored separately.
- Raw materials are mixed in proper proportion by automatic weighing machines and then mixture is pulverized finely.
- Mixture is burnt into rotary kiln. (Rotary kiln is a steel cylinder, lined with fire bricks having near about 3m dia.)
- During heating lime stone decomposes. This product is called as clinker.
- Clinkers are cooled, mixed with 2-3% gypsum and pulverized.
What is wet process of cement manufacturing?
- In the wet process, the lime stone crushed to smaller fragment. And take in to storage tank
- This stored lime stone then taken in to slurry grinder.
- From another side clay is taken in to grinding mills to make slurry by washing.
- This mixture of clay and lime stone then grinding to make slurry.
- Then correct composition is blending out.
- Then corrected slurry stored.
- Then it transferred to rotary kiln.
- Then converted clinkers are taken in to ball mill.
- During this grinding gypsum is added up to 2-3%.
- Then crushed powder stored in silos.
- Then fine powdered cement packed in bags.
What are the types of cement?
Ordinary Portland Cement
(OPC):
Properties:
- It is basic type of cement.
- Due to maximum percentage of iron oxide greenish in colour.
- It is used for general concreting work.
- This is most common type of cement and used for all general purposes.
Uses:
- For construction of building.
- For plastering of walls.
- For RCC work like slab, beam, column, etc.
- For bridge and road.
White Cement:
Properties:
- Percentage of iron oxide is vary less (below than 1%)
- Colour is white.
- It has good water proofing property.
- Its strength and other properties are similar to OPC.
- It is generally used for decorative purpose.
Uses:
- It used for filling the joints between glazed tiles or dado tiles.
- It used for decorative purpose.
- It used in swimming pool construction.
- It used in traffic signaling work.
Coloured Cement:
Properties:
- It produced by adding some colour pigments in white cement.
- Darkness of shade depends on percentage of pigments.
- It not has any strength.
- It only used for the decoration purposes.
Uses:
- For floor finishing.
- For grouting in coloured tiles.
- Decorating external surfaces.
- Improve appearance.
What are the different brands of cements are available in market?
L&T (Larsen &
Turbo), Ambuja cement, Birala Shakti, Binani Cement, JK cement, ACC cement,
Ultratech cement, etc.
What is grade of cements?
Grade 33 means that the compressive strength
of cement mortar (1:3) cube of 7.06cm size after 28 days curing in water is
33N/mm2. In market 33, 43, 53 grade cement is available.
What is the common packing available in market?
- The packing of cement is generally done by paper or plastic bags.
- Such bags are technically superior and avoid absorption of moisture.
- In market low size bags are available i.e.1kg, 2kg, 5kg, 10kg, etc.
- In our country commonly 50kg cement bags are easily available.
- Sometimes jumbo bags are packed of 200kg.
Which are common field test on cement?
- Lump test: there should not be any visible lumps.
- Colour test: It is normally greenish in colour.
- Hand Feeling test: Insert hand in to cement bag it should give a cool feeing. Take pinch of cement in finger it should be give smooth feel not a gritty.
- Water float test: Take handful cement and throw it on water, the particles shuld foat for some time before it sinks.
- Strength test: Take 100gm cement and small quantity of water and make a paste. From this paste, prepare cake with sharp edges. Put it on a glass plate and slowly take in under water in a bucket such that its shape not disturbed. After 24hrs cake should retain its original shape and at the same time it should also set some strength.
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