Cement rates and tests for construction.

1. Cement
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2. What is cement?
■ A cement is a binder, a substance used for construction that
sets, hardens, and adheres to other materials to bind them
together.
■ Cement mixed with fine aggregate produces mortar for
masonry, or with sand and gravel, produces concrete.
■ It has a property of setting and hardening when mixed with
water.

3. Types of cement
1. Ordinary Portland Cement(OPC)
It is the most widely used type of cement which is suitable for all general
concrete construction.
2. Portland Pozzolana Cement (PPC)
Portland pozzolana cement is prepared by grinding pozzolanic clinker
with Portland cement.
This cement has high resistance to various chemical attacks on
concrete compared with ordinary Portland cement and thus it is
widely used. It is used in marine structures, sewage works, sewage
works and for laying concrete under water such as bridges, piers,
dams and mass concrete works etc.
3. Rapid Hardening Cement-
Rapid hardening cement attains high strength in early days it is
used in concrete where formworks are removed at an early
stage and is similar to ordinary Portland cement (OPC).

4. 6. White Cement
■ It is prepared from raw materials free from Iron oxide and
is a type of ordinary portland cement which is white in
color.
■ It is costlier and is used for architectural purposes such
as precast curtain wall and facing panels, terrazzo
surface etc. and for interior and exterior decorative work
like external renderings of buildings, facing slabs,
floorings, ornamental concrete products, paths of
gardens, swimming pools etc.

5. Grade of cement
1]53 grade-
Setting time is 3 hrs.
used to make concrete, steel crust, RCC.
it has compressive strength 53 Mpa.
2]43 grade-
Setting time 5-6 hrs.
used for plastering, water proofing, etc.
it has compressive strength 43 Mpa.
3] 33 grade-
Setting time 10 hrs
used for general constructions.
it has compressive strength 33 Mpa.

6. Market survey report-
1]Birla shakti-
a) 43 grade- Rs.330/bag
b) 53 grade- Rs.384/bag
2]Birla white portland cement- Rs.1085/bag
3] J.K. super cement-[opc waterproof]
a)43 grade- Rs.325/bag
b) 53 grade- Rs.325/bag
c) 33 grade- Rs.325/bag
4]Bharti cement-
a) 43 grade- Rs.325/bag
b) 53 grade- Rs.315/bag
5]Chettinad cement-
a) 53 grade- Rs.310/bag
b) 43 grade- Rs. 310/bag

7. LAB TESTS FOR CEMENT
■ Fineness Test
■ Consistency Test
■ Setting time Test
■ Soundness Test
■ Strength Test
■ Heat of Hydration Test
■ Specific Gravity Test

8. ■ Fineness Test :-
Fineness is the mean size of cement grain. It is done to
measure the mean size of cement grain.
One of the Following three methods can be applied to test the fineness of
cement-
I. Sieve method
II. Air Permeability method
III. Sedimentation method

9. ■ Sieve method :-
After shacking the cement for 10 min. The initially taken amount of cement and
the residual amount is noted down.
Fineness % = Residual cement on sieve x 100
Initially taken sample

10. ■ Consistency Test :-
This physical test of cement is done to estimate the required water quantity to
form a normal consistency cement paste. It is defined as the percentage of
water required form the cement paste.

11. ■ Setting Time Test :-
Cement has two types of setting time – Initial setting time and Final setting
time.
Initial setting time is the state of cement mortar or concrete when it starts to
become stiffen and unworkable.
Final setting time is the state when cement mortar or concrete has become
fully unworkable.
Two methods are used to find the initial and final setting time of cement :-
I. Vicat needle method
II. Gillmore needle method

12. Vicat needle method

13. ■ Soundness Test :-
The soundness of cement means it doesn’t undergo large volume change after
setting. Large changes in volume produce cracks, disintegration, and
distortion, ultimately leading to failure.
To test the soundness two methods can be applied :-
I. Le-Chatelier method

14. ■ Strength Test :-
Cement has two types of strength – compressive strength and tensile strength.
To know the compressive strength and the tensile strength of cement following
tests are performed –
I. Cement mortar cube test (for compressive strength)
II. Briquette test (for tensile strength)
III. Split tensile test (for tensile strength)

15. ■ Heat of Hydration Test :-
Cement produces a large amount of heat during the hydration process. When
a large amount of concrete volume is poured the inner temperature is greater
than the outer surface of the concrete. Because the outer surface is exposed
to the weather. Thus the outer surface shrinks rapidly than the inner surface
and tends to produce cracks.
Following test is performed to know the heat of hydration of cement :-
I. Calorimeter method

16. ■ Specific Gravity Test :-
The specific gravity of cement is a comparison of the weight of a cement
volume to the weight of the same volume of water.
Le-Chaterlier flask is used to test the specific gravity of cement.

17. FIELD TESTS FOR CEMENT
■ Smoothness Test :-
When cement is touched or rubbed in between fingers, it should give a smooth
feeling. If it felt rough, it indicates adulteration with sand.
■ Water Sinking Test:-
If a small quantity of cement is thrown into the water, it should float some time
before finally sinking.
■ The smell of Cement Paste:-
A thin paste of cement with water should feel sticky between the fingers. If the
cement contains too much-pounded clay and silt as an adulterant, the paste
will give an earthy smell.
■ Glass Plate Test:-
A thick paste of cement with water is made on a piece of a glass plate and it is
kept under water for 24 hours. It should set and not crack.

18. ■ Block Test:-
A 25mm × 25mm × 200mm (1”×1”×8”) block of cement with water is made.
The block is then immersed in water for three days. After removing, it is
supported 150mm apart and a weight of 15kg uniformly placed over it. If it
shows no sign of failure the cement is good.

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