mixing of concrete, msu-polytechnic-2014-15

1. WEL-COME

2. THE MS UNIVERSITY OF BARODA
POLYTECHNIC
Second sem., S.y.d.civil
Roll no: 34 to 44
CIVIL ENGINEERING DEPARTMENT

3. TOPICS:
1. WHAT IS CONCRETE
2. INGRADIENTS OF CONCRETE
3. VARIOUS TYPES OF CONCRETE
4. PROPOSTIONING OF CONCRETE
5. BATCHING OF CONCRETE
6. WATER CEMENT RATIO
7. MIXING OF CONCRETE
8. SLUMP TEST
9. WORKABILITY
MIXING OF CONCRETE

4. It is simply defined as the mixture of
cement , fine aggregates , coarse aggregates , water
, admixtures
 Concrete used on worked is specified according to
IS 456(2000) .
 It is one of the very important and widely used
material in construction .
 concrete = binder + fillers
Cement ,
water,
admixture
Fine aggregates
and coarse
aggregates
(which occupies
around 60%)
CONCRETE

5. INGREDIENT
cement
If fills up voids existing in fine aggregates.
It provides strength and binding properties to the
concrete mixture.
Fine
aggregate
The particles which passes from IS sieve 4.75 mm &
should be retained from 75 micron is known as fine
aggregates.
It should not contain any organic material.
The main function of fine aggregate is to fill-up voids
existing in coarse aggregates.
Coarse
aggregate
The particles which are retained through IS sieve 4.75
is known as coarse aggregates.
Coarse aggregates should be hard & strong to give
enough strength and durability to concrete.

6. INGREDIENT
Water
Water acts as a lubricant for the aggregates and
gives workability to the concrete.
The quality of concrete depends on the quality and
quantity of the water added.
Admixture
Admixtures or additives as required by situation,
ingredients added to concrete or mortar modifies its
properties immediately before or after mixing.

7. Admixtures
1. Chemical admixture
 (for specific property i.e. performance &
enhancement)
2. mineral admixture
 (for improvement of long – term strength & durability)
others :
 Air entraining admixtures.
 High range of water reduces or super plasticizers.
 Normal range of water reducers or plasticizers &
retarders.

8. Types of concrete
According to design of
concrete:
 P.C.C. (Plain cement concrete)
 R.C.C. (Reinforcement cement concrete)
 B.B.C.C. (Brick bats cement concrete)
 B.B.L.C (Brick bats lime concrete)

9. According to grade it is
defined as:
 The grade of concrete is specified by its 28 Day’s
cube strength ( e.g. M20 means the cube strength
is 20 N/sq. mm)
M7.5 1:4:8
M10 1:3:6
M15 1:4:8
M20 1:1.5:3
M25 1:1:2

10. PROPORTIONING OF
CONCRETE
Methods
 By designing the concrete mix.
 By adopting nominal mix.
 Arbitrary method.
 Fineness modulus of method.
 Maximum density method.
 Maximum voids method.
 w/c ratio method (water cement ratio).

11. • Batching is the process of measurement of
specified quantity of ingredient in correct
proportion batching is done by two process.
1. By volume batching :
• Batching by volume means measuring
ingredient of concrete by its volume.
2 . By weigh batching :
• Batching is done according to the weight of
ingredients. It is more preferable method to
volume batching.
BATCHING OF CONCRETE

12. Batching
 The equipment falls into three
categories in both batching process
as follow:
1. Manual batching
2. Semi-automatic batching
3. Fully-automatic batching

13. Volume batching
Batching by volume means the measurement of ingredients is
done by volume.
 Generally cement is measured by weight or number of bags.
 Batching of aggregate should be done with the Forma or
Cage Box
 Batching of water is done with the help of calibrated canes &
the measuring accuracy should be within 1%.
 Batching of admixture should be done as same accuracy for
cement (mineral admixture) and water (chemical admixture).
 For e.g. proportion (1:2:4)
 i.e. 1 part of cement
 2 part of sand
 3 part of coarse aggregates

15. weigh batching
 Batching is done by the weight of ingredient. It is
more preferable than volume batching. It is more
accurate & needs more uniform proportioning.

16. For the process of hydration dry mix of ingredients , the water is
added.
The water make the concrete mix workable.
According to Abram’s w/c law , lesser the w/c ratio in a workable
mix , greater will be the strength.
The lower water content will produce stiff paste having greater
binding strength will be increase.
Higher water will increase the workability but decrease the strength
of the concrete mix.
Generally a minimum w/c ratio is taken 0.3 by weight.
Typical values are 0.4 to 0.6 .
w/c ratio= water
cement
Water-cement ratio

17. Water cement ratio
Concrete ratio quantity Water
1:3:6 34 litre
1:2:4 30 litre
1:1.5:3 27 litre
1:1:2 25 litre
For different ratio of concrete the amount of water for 50 kg
of cement is as below:

18. Mixing of the concrete
 For producing the homogeneous mass of concrete , the
ingredient are mixed . Depending upon the
requirement , quality , quantity , etc, the method of
mixing is decided.
 Generally there are two methods for mixing the
concrete ,
o 1. hand mixing :
 by manual labors
 Small works
o 2 . Machine mixing :
• For big works where requirement is continuous
• Mixed automatically in batching plants

19. Hand mixing
 In this type , the mixing is done by manual labors.
 This method is adopted for small construction
works .
 Requirement of cement is more than machine
mixing (10%).
 Normally the mixing time is about 3 minutes.

20. Hand mixing procedure
 Construction of platform of bricks , lean concrete
or iron-sheet.
 Spread-out sand evenly , spread cement on it.
 Mix it till the color of mixing become uniform.
 Spread this mixture & spread coarse admixture
then mix it.
 During mix it remaining water should be added
with continuation process.
 Time for mix is generally 2 to 3 minutes.

21. Hand mixing

22. Machine mixing
 This is similar to hand mixing only the mixing is
carried out in a rotating drum

23. Machine mixing
For machine mixing , all the ingredients of concrete
including water are collected in a revolving drum
and then the drum is rotated for a certain period.

24. Machine mixing

25. Machine mixing
 Types of machine mixing
1. Manual mixer
2. Electrical mixer
3. Fuel mixer

26. R M C
( Ready Mix Concrete )
 Ready – mix concrete is type of concrete that is
manufactured in a factory or batching plant ,
according to design and then delivered to a work
site , by transit truck.
 RMC is bought and sold by volume.
 The truck carries a mix in a revolving chamber
which like the concrete mixer . It prevents the
segregation of concrete .

27. RMC
( Ready Mix Concrete )
 It is manufactured
under computer-
controlled operations
and transported and
placed at the site of
constructed.

28. RMC
( Ready Mix Concrete )

29. Advantages of ready mix
concrete
 Better quality concrete is produced.
 storage space for basic materials at site is not
required .
 Wastage of basic materials are avoided.

30. Workability
 It is desirable that freshly mixed concrete be
relatively easy to transport , place , compact and
finish without harmful segregation.
 A concrete mix satisfying these condition is said to
be workable.
 Use of aggregates which are round and have
smooth surface increases the workability.

31. Slump Test
 This test is performed for getting rough idea of workability.
 Procedure:
 Place frustum on the base plate.
 Fill the wet concrete mixture in the cone in three equal layers.
 Compact each layer 25 times using compacting steel rod and
the top surface is struck off by means of a sawing and rolling
motion of the temping rod.
 The cone is slowly lifted and observed the slump.
 Invert the frustum and place it close to the collapsed concrete.
 Measure and record the slump and type of slump.
 The slum can be measure as shown in figure.

32. Slump test

33. Slump test
 Results:
 There are three types of slump that can happen
which are:
 True slump
 Shear slump
 Collapsed slump as shown in the below figure.

34. Slump test

35. Group members
Jadav Keyur
Jangid Rinku
Joshi Parth
Kachipulav Ishtiyaq
Kachot Nilesh
Kadam Karan
Kadu Mayur
Katariya Kiran
Kharva Nehal
Kharva Jaina

36. We are thankful to….
 All respected lecturers and all supported
members for preparation of this presentation…
Special thank to,
Lafarge Pvt. Ltd., Harni (Baroda)
(RMC batching plant)

37. Thank you
To all of you……