Concrete is an engineering material that simulates the properties of rock and is a combination of particles closely bound together. It is simply a blend of aggregates, normally natural sand and gravel or crushed rock. Cement is a dry powdery substance made by calcining lime and clay, mixed with water to form mortar or mixed with sand, gravel and water to make concrete. It is a binder material. Once hardened, cement delivers sufficient strength to erect large industrial structures Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore. Sand a loose granular material that results from the disintegration of rocks, consists of particles smaller than gravel but coarser than silt, and is used in mortar, glass, abrasives, and foundry molds. : soil containing 85 percent or more of sand and a maximum of 10 percent of clay. Concrete, Cement Raw Material of Cement, Types Water, Aggregates, Sand Mixing of concrete Transportation, Rate Analysis

1. Concrete is a product or mass, made by the use of cement,
water and aggregates(fine and course).

3.  Cement in general can be defined as a material,
which possesses very good adhesive and cohesive
(cementation) properties, which make it possible to
bond with other materials to form a compact mass.
 The cement used for construction is known as
portland cement.

5. Lime (CaO) 60 to 67%
Silica (SiO2) 17 to 25%
Alumina (AL2O3) 3 to 8%
Iron Oxide (Fe2O3) 0.5 to 6%
Magnesia (MgO) 0.1 to 4%
Sulpher trioxide (SO3) 1 to 2.25%
Alkalies (soda & potash) 0.5 to 1%

6. 1) Ordinary portland cement.
2) Rapid hardening cement.
3) Quick setting cement.
4) Low heat cement.
5) Blast furnace cement.
6) High alumina cement.
7) Expanding cement.
8) Sulphate resisting cement.
9) White cement.
10) Coloured cement.

7.  Ordinary Portland Cement:-
It is basic portland cement and is used in all general masonry and concrete
construction works
 Rapid Hardening Cement:-
as the name implies, it develops strength rapidly, and therefore can be called as high
early strength cement. The rate of setting is same as that of ordinary port land cement.
The strength of this cement at the age of 3 days is equal to the 7 days strength of
ordinary port land cement with the same w/c ratio.
Requirements of soundness and chemical composition are same as those of ordinary
port land cement.
This cement is used where a rapid strength development is desired, e.g., when frame
work is to be removed for re-use, or where sufficient strength for further construction is
wanted as quickly as practicable.

8. This cement is obtained by inter grinding calcium chloride with
rapid hardening cement. The quantity of calcium chloride should
not exceed 2 percent. The cement must be stored under dry
conditions and it should generally be used with in one month of
dispatch from the factory.
This cement is suitable for cold weather concreting ,or when a very
high early strength is required. Setting time is short, depending on
temperature it can be b/w 5 to 30 minutes requiring early placing .
its use in pre-stressed work is prohibited.
• Quick setting cement:-
This cement sets very early. The early setting property is
brought out by reducing the gypsum content at the time of clinker
grinding. This cement is required to be mixed, placed, and
compacted very early. It is mostly used in under water construction
or where pumping is involved. It may also be used for some typical
grouting operation.

9.  The rise in temperature in the interior of a large concrete mass due to
the heat of hydration can lead to serious cracking.
 The heat of hydration should not exceed 65 calories/gram and 75
calories/gram at the end of 7 and 28 days respectively.
Blast Furnace Cement:-
 This type of cement is made by intergrinding portland cement clinker
and granulated blast furnace slag.
 The proportion of slag being limited to 65% of the weight of mixture.
ordinary portland cement blast furnace
cement
After 3 days 160 kg/cm2 112 kg/cm2
After 7 days 220 kg/cm2 210 kg/cm2
at higher ages the difference in strength is very less.

10.  High alumina cement is also known as aluminous cement or aluminate
cement.
 This cement used is to resist the attack of gypsum bearing water and
chemical attack.
 This cement is manufactured in many European countries and in the
united states of America.
Expanding cement:-
 Expanding cement blended with normal cements may be used to form
a concrete which neither shrinks nor expands.
 The expanding agent is calcium sulpho –aluminate 5%.
 Thy are used for grouting anchor bolts, machine foundation and ducts
in pre-stressed members, drill holes in rocks.

11.  Sulphate portland cement is very similar to ordinary portland cement
except that the quantity of tricalcium aluminate (C3A) which is the least
stable compound is strictly limited to about 5%
 This cement is ground rather finer than ordinary cement.
 This concrete made from this cement is used in marine conditions and
fabrication of pipes.
White portland cement:-
 The process of manufacturing white cement is the same but the amount of
iron oxide is limited to less than 1%.
 White cement generally satisfies the usual specifications but it is not so
strong as ordinary portland cement.
 It is more costly.
 Snow Crete is a trade name of such cement.
 Sodium alumino fluride is added during burning which acts as a catalyst in
place of iron.

12.  The different forms of cement have their own characteristic colours,
but most coloured cement are basically portland cements to which
pigments have been added
 Strong pigments Can be added to ordinary portland cement in
quantities up to 10% .
General uses of cement:-
 Making mortar for the masonry work.
 Making mortar for plastering.
 Making mortar for pointing.
 Making plain cement concrete and reinforced cement concrete.
 For making soil cement blocks
 Specific uses of various type of cement are already given against each
type.

13. Main function of water is to react with cement to form a binding matrix,
which binds with the aggregates to form a hardened concrete. Generally
one part by weight of cement requires 0.3 parts by weight of water for
hydration. But extra water is required to lubricate the mix and to make it
workable.
A water fit for drinking is suitable or fit for concrete. Hence minimum
water- cement ratio required is 0.3. but concrete containing water in this
proportion is very dry and difficult to place. extra water is required to
lubricate the mix, which make the concrete workable. This extra water
must be kept to the minimum, since too much water reduces the strength
of the concrete. The exact amount of excess water or water cement ratio
required depend upon the grade of the concrete, nature and types of
aggregates, the compressive strength of concrete, required workability,
etc.

14. Water available at site may have the following impurities.
It may contain clay, silt, and other suspended particles like vegetable or
animal matter. All these suspended impurities cause turbidity in water.
Water may also contain soluble impurities like carbonates, bicarbonates,
chlorides and sulphates of magnesium, calcium and alkali metals. The
several thousand ppm in mineral/spring water. Other impurities like
silica, iron, alumina and nitrates may also be present but in small
quantities.
Bacteria or other bacteriological contamination may be present.
Dissolved gasses such as CO2, O2, and N2 are also present.

15. impurity Tolerable concentration
Sodium and potassium
carbonates and bi-carbonates.
1000 ppm (total). If this is
exceeded, it is advisable to make
tests both for setting time and 28
days strength.
chlorides 10,000 ppm
Sulphuric anhydride 3000 ppm
Calcium chloride 2 percent by weight of cement in
non pre-stressed concrete.
Sodium iodate, sodium sulphate,
sodium arsenate, sodium borate.
Very low.
Sodium sulphide Even 100 ppm warrants testing
Sodium hydroxide 0.5 % by weight of cement,
provided quick set is not
induced.
Silt and suspended particles 2,000 ppm. Mixing water with a
high content of suspended solid
should be allowed to stand in a
settling basin before use.

16.  “Inert materials which when bonded together by cementing material in
concrete is called aggregates”. They provide bulk of mass of concrete.
Approximately ¾ of volume of concrete is occupied by aggregates.
 Classification of aggregates
Aggregates may be classified as under.
According to nature of formation
According to size
According to shape
Detail
According to nature of formation
According to nature of formation
Igneous rocks
Sedimentary rocks
Metamorphic rocks

17. According to size
 Fine aggregates
 Course aggregates
Detail
Fine aggregates
The size of aggregates, less then 4.75mm (3/16”) is called fine
aggregates. In the fine aggregates.
 Sand
 Stone dust
 Cinder
 Surkhi
According to size

18. There are three types of sands
 Pit sand
 River sand
 Sea sand
 Sand characteristic
 Good sand should have coarse and angular grains of poor silica.
 The grains of sand should be hard strong and durable.
 It should be free from silt, clay or any such salts iron pyrites, alkalies,
etc.
 It should not contain any organic matter.
 It should be well graded i.e. should contain in suitable proportional
particles of various size.
 It should not contain any hygroscopic matter.

19. the size of aggregates, 4.75mm to 75mm (3/16” to 3”) is called coarse aggregates. In the coarse aggregates,
 Stone ballast
 Gravel
 Brick ballast
 Clinker
Characteristics of coarse aggregates
 It should be clean from dust, clay and other organic impurities.
 Coarse aggregates should be hard enough to resist wear.
 It should be tough to resist impacts, and strong in compression.
 The specific gravity for general purpose concrete, should range from 2.6-2.7.
 It should be properly graded.
 It should be non reactive with alkalies.
CLINKER

21.  Rounded aggregates
 Irregular aggregates
 Flaky aggregates
 Elongated aggregates
 Angular aggregates
Concrete batching
The proper and accurate measurement of all the materials used in
essential to ensure uniformity in successive batches.
the measurement of materials for making concrete is known as
batching. There are two methods of batching.
 By volume batching
 By weight batching
According to shape

22.  After measuring the different ingredients of concrete the next operation is their
mixing. The mixing should ensure that the mass becomes homogeneous, uniform
in colour and consistency. Segregation should not take place during mixing
operation. There are two methods of mixing.
 Hand mixing
 Machine mixing
Method of transportation of of concrete
 Steel pan method
 By wheel barrow
 By dumper
 By tripper
 By truck mixer
 By tower lift
 By cable way
 By crane
 By pumping

23.  Factor affecting of transportation of concrete
 Time factor
 Prevention from segregation
 Check against loss of water
 Easement in use
 Yield of concrete

24.  Prepare analysis of rates for cement concrete (1:2:4).
The size of roof slab (50’x14’x6”).
Solution:
Volume of slab=14’x50’x0.5’=350 cft
Dry volume of material=350x1.54=539 cft
Ratio of concrete= 1:2:4
Sum of ratio= 1+2+4=7
Material required:-
Quantity of cement= 1/7x539=77 cft
cement in bags =77/1.25=61.6 say 62 bags

25. Cost of labour:-
1 mason @ Rs.500/no/day=1x500=500 Rs
5 coolies @ Rs. 300/no/day=5x300=1500 Rs
Total cost of labour= 500+1500=2000 Rs
Total cost= 38680+2000=40680 Rs.
Add 10% contractor profit=10/100x40680=4068
Total cost of estimate=40680+4068=44748 say
=44500 Rs.

26. Quantity of sand=2/7x539=154 cft
Quantity of bajri=4/7x539=308 cft
Cost of material:-
Cost of cement @Rs.450/bag=62x450=27900 Rs
Cost of sand @Rs.10/cft=10x154=1540 Rs
Cost of bajri @ Rs. 30/cft=30x308=9240 Rs
Total cost of material=27900+1540+9240=38680
Cost of carriage:-
Nil, as all material are to be supplied
at site.