ctep - unit - ii - cement
Post on 12-Apr-2017
61 Views
Preview:
TRANSCRIPT
CEMENTCEMENT
1
BY K.R.SHANKAR M.E.,
ASSISTANT PROFESSOR DEPARTMENT OF CIVIL ENGINEERING
EBET GROUP OF INSTITUTIONS TRIPPUR DISTRICT
TAMUL NADU, INDIA – 638108 Email ID – krs.civil@ebet.edu.in
WHAT IS CEMENT???? Material with adhesive and cohesive properties
Any material that binds or unites - essentially like glue
2
FUNCTION OF CEMENT
To bind the sand and coarse aggregate
together to fill voids in between sand and coarse
aggregate particle to form a compact mass
3
Oxide Common Name Approx. Amount (%)
CaO Lime 60-67
SiO2 Silica 17-25
Al2O3 Alumina 3-8
Fe2O3 Iron-oxide 0.5-6
MgO Magnesia 0.1-4
Na2O Soda0.2-1.3
K2O Potassium
SO3 Sulfuric Anhydride 1-3
CONSTITUENTS OF CEMENT
4
FUNCTIONS OF INGREDIENTS
Lime
Lime is the important ingredient of cement and its proportion is to be
maintained carefully.
Lime in excess makes the cement unsound and causes the cement to expand
and disintegrate.
On the other hand, if lime is in deficiency the strength of the cement is
decreased and it causes cement to set quickly
5
Silica: This also an important ingredient of cement and it
gives or imparts quick setting property to imparts strength to
cement.
Alumina: This ingredient imparts quick setting properly to
cement. Excess alumina weakens the cement.
Calcium Sulphate: This ingredient is in the form of gypsum
and its function is to increase the initial setting time of
cement.
6
Magnesia: The small amount of this ingredient imparts hardness and
colour to cement. Excess Magnesia affects soundness of the cement.
Sulphur: A very small amount of sulphur is useful in making sound
cement. If it is in excess, it causes the cement to become unsound.
Alkalies: Most of the alkalies present in raw material are carried away
by the flue gases during heating and only small quantity will be left. If
they are in excess in cement, efflorescence is caused.
Iron Oxides: Provides color, hardness and strength. It also assits in
fusion of raw materials in manufacturing of cement.
7
Best binding material
High plastic properties
High strength
Hardens in short time
High resistance to water and other atmospheric effects
PROPERTIES OF CEMENT
8
QUALITY REQUIREMENTS OF CEMENT
Homogeneous and uniform in colour
Free from lumps and should sink in water in small
quantity is placed on surface of water
Ratio of percentage of alumina to that of iron oxide
should not be less than 0.66
Weight of magnesia not exceeds 5%
9
Total sulphur content not exceeds 2.75%
Specific surface should minimum 2250 mm2/gm
Expansion of cement should not exceeds 10 mm
Initial setting time should not be less than 30 mints.
Final setting time should be around 10 hours
10
11
GRADE OF CEMENT:
The commonly used Portland Cement in India are as follows
1. 33 Grade (IS 269:1989)
2. 43 Grade (IS 8112:1989)
3. 53 Grade (IS 12269:1987)
The Grade is nothing but its 28 days mean compressive
strength of mortar cube. For
1. 33 Grade it must be exceeding 33 N/mm2
2. 43 Grade it must be exceeding 43 N/mm2
3. 53 Grade it must be exceeding 53 N/mm2
TYPES OF CEMENT Rapid Hardening Cement
Quick setting cement
Low Heat Cement
Sulphates resisting cement
Blast Furnace Slag Cement
High Alumina Cement
White Cement
Coloured cement
Pozzolanic Cement
Air Entraining Cement
Hydrographic cement
12
Types of Cement Purpose
Rapid Hardening
Cement
Attains high strength in early days it is used in concrete where form work are removed at an early stage.
Quick setting cement
Used in works is to be completed in very short period and concreting in static and running water
Low Heat Cement
It is used in massive concrete construction like gravity dams
Sulphates resisting Cement
It is used in construction exposed to severe sulphate action by water and soil in places like canals linings, culverts,
retaining walls, siphons etc.,
Blast Furnace Slag Cement
It can used for works economic considerations is predominant.
13
High Alumina Cement
It is used in works where concrete is subjected to high temperatures, frost, and acidic action.
White CementIt is more costly and is used for architectural purposes
such as pre-cast curtain wall and facing panels, terrazzo surface etc.,
Coloured cement They are widely used for decorative works in floors
Pozzolanic Cement
It is used in marine structures, sewage works, sewage works and for laying concrete under water such as
bridges, piers, dams etc.,
Air Entraining Cement
This type of cement is specially suited to improve the workability with smaller water cement ratio and to
improve frost resistance of concrete.
Hydrographic cement This cement has high workability and strength
14
15
Masonry Cement They are widely used for masonry work
Oil-well Cement
It is used in high pressure and temperature in sealing water and gas pockets and setting cause during the
drilling and repair of oil well
Expanding Cement
This type of cement is used in repairing concrete surface
Acid Resisting Cement
It is used in chemical industry
top related