THE MS UNIVERSITY OF BARODA
Second sem., S.y.d.civil
Roll no: 34 to 44
CIVIL ENGINEERING DEPARTMENT
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
MIXING OF CONCRETE
It is simply defined as the mixture of
cement , fine aggregates , coarse aggregates , water
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
If fills up voids existing in fine aggregates.
It provides strength and binding properties to the
The particles which passes from IS sieve 4.75 mm &
should be retained from 75 micron is known as fine
It should not contain any organic material.
The main function of fine aggregate is to fill-up voids
existing in coarse aggregates.
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.
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.
Admixtures or additives as required by situation,
ingredients added to concrete or mortar modifies its
properties immediately before or after mixing.
1. Chemical admixture
(for specific property i.e. performance &
2. mineral admixture
(for improvement of long – term strength & durability)
Air entraining admixtures.
High range of water reduces or super plasticizers.
Normal range of water reducers or plasticizers &
According to grade it is
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)
By designing the concrete mix.
By adopting nominal mix.
Fineness modulus of method.
Maximum density method.
Maximum voids method.
w/c ratio method (water cement ratio).
• 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
BATCHING OF CONCRETE
The equipment falls into three
categories in both batching process
1. Manual batching
2. Semi-automatic batching
3. Fully-automatic 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
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
Batching is done by the weight of ingredient. It is
more preferable than volume batching. It is more
accurate & needs more uniform proportioning.
For the process of hydration dry mix of ingredients , the water is
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
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:
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
o 1. hand mixing :
by manual labors
o 2 . Machine mixing :
• For big works where requirement is continuous
• Mixed automatically in batching plants
In this type , the mixing is done by manual labors.
This method is adopted for small construction
Requirement of cement is more than machine
Normally the mixing time is about 3 minutes.
Hand mixing procedure
Construction of platform of bricks , lean concrete
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.
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 .
( Ready Mix Concrete )
It is manufactured
and transported and
placed at the site of
Advantages of ready mix
Better quality concrete is produced.
storage space for basic materials at site is not
Wastage of basic materials are avoided.
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
Use of aggregates which are round and have
smooth surface increases the workability.
This test is performed for getting rough idea of workability.
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.