1. Advances in Concrete Technology
By,
M. Mayur,
Siddharth Institute of Engineering and Technology,
Puttur.
Abstract: Workability. Cement is main and most
important material in Concrete. It is a
Concrete is the only binding material which mixture of Calcareous Materials and
is used from ages till now. But we did not Argillaceous Materials. These materials can
find any kind of material which replaces it. be mixed in presence of water and also in
Since it is a mixture of Cement, Aggregates absence of water. Wet Process means
and Water in a required or calculated ratio. mixing of raw materials used for cement in
But advances in concrete technology presence of Water and Dry Process means
includes the properties of concrete such as mixing them even in presence of water but
Workability, Strength, Durability and so on. not as much as Wet Process. After
But this present scenario describes about completion of all above processes, we get
Advances in Concrete Technology such as Cement in a bag of 50 kgs.
Admixtures, Plasticizers, Super plasticizers,
Retarders. The usage of these materials has
become a lift for Structural Engineers to
bring down big constructions in usage in a
smaller time. But in general, Advances in
Concrete Technology deals with increase in
Strength and Durability of Concrete and
increasing Workability to required time. So,
the present paper deals with Advances in
Concrete Technology and their impacts on
structures building by using them.
An aggregate includes Fine Aggregates and
Coarsed Aggregates. Fine Aggregates
includes Sand and Coarsed Aggregates
Introduction: includes Gravels.
Concrete is a mixture of Cement,
Aggregates and Water. Cement is most
important material in Concrete. An
aggregate consumes about 70% - 80% of
volume of Concrete. Water is used to bind
the above materials and to give some

2. Fresh Concrete is such concrete in which
Concrete is in plastic state. Hardened
Concrete is next to Fresh type of Concrete
means it gains 90% more strength than
Fresh Concrete. Each of the above
concrete’s has their own uses and their own
applications and their properties unique to
them.
The above diagram shows different types of
Aggregates such as Rounded, Flaky and Advances in CT:
Irregular Shapes of Aggregates. Aggregates
also have some strength. The main advances in CT deals with action
of :
Properties:
 Plasticizers,
The main properties of Concrete are
Workability, Strength, Durability, Elasticity,  Super plasticizers,
Creep and Shrinkage. The advances in
 Retarders,
Concrete Technology mean increase in
Strength, Workability and Durability of  Accelerators,
Concrete.
 Air – entraining admixtures,
Types of Concrete:
 Puzzolanic Admixtures,
There are different types of Concrete. Some
of them are:  Damp – proofing Admixtures,
 Fresh Concrete  Gas forming Admixtures,
 Hardened Concrete  Workability Admixtures,
 Special Concrete  Bonding Admixtures,
 Light – Weight Concrete  Colouring Admixtures and
 Fibre Reinforced Concrete  Corrosion Inhibiting Admixtures.
 Reinforced Cement Concrete Not only these, but these also includes
Construction Chemicals such as:
 High Density Concrete
• Concrete Curing Compounds,
 Self Compacting Concrete(SCC)
• Mould Releasing Agents,
• Non – shrink high Strength Grout,
• Surface Retarders,
• Ready to use Plaster,
• Guniting Aid and

3. • Protective Coatings. 1. These are Water Reducers.
The above mentioned Compounds are useful 2. In general, the water – cement ratio
in not only increasing Strength, Durability of concrete is 0.40, but when these
and Workability of Concrete but they are are used they reduce w/c ratio to 5%
also useful in giving protection to concrete, to 15%.
creates bonds between the materials of
concrete, and gives attractive colours to 3. The reduction of w/c ratio naturally
concrete and also they reduce water to a increases Strength of Concrete.
great extent which is a severe crisis in now – 4. These are composition of
a – days. lignosulphonates, salts of
In past times, while construction of sulphonates hydrocarbons.
bridges, they construct piers to support 5. They contain nonionic surfactants
bridges which are to be constructed in a such as polyglycol esters, acid of
deep way below the water level in Sea or hydroxylated carboxylic acids.
River. That was a serious problem at those
times. Since, some of problems such as: 6. Efficient Plasticizer is one which
does not cause air – entrainment in
 At such great depths, temperature
concrete more than 1% - 2%.
will be high and concrete can loose
moisture at those depths, and it sets 7. Dispersion Effect and Retarding
from that point. Effects are main actions of
Plasticizers.
 Transportation of Concrete to such
great depths is also a problem with
help of pulleys etc…
 Not only in depths, but when tallest
buildings are constructed concrete is
to be transported to top most floor of
building which has to take place with
in 5 minutes, since the initial setting
time of OPC is 5 min.
From that point of view, some of experts
observed the properties of Concrete, and Action of Super plasticizers:
they gave some formulae for initial and final
setting time of concrete, from which 1) These are High Range Water
concrete can be made to gain early strength Reducers.
and also at the same time to gain strength
2) Their use was developed in Japan
even after 30 min. So, this can be said as
and Germany in 1960 and 1970.
ADVANCES IN CONCRETE
TECHNOLOGY. 3) Usage of Super plasticizers reduces
the w/c ratio upto 30% without
Explanation of Compounds:
reducing workability.
Action of Plasticizers:

4. 4) They reduce w/c ratio to 0.25 or even a. Accelerators are also mixed with
more. plasticizers.
5) They can produce more workable b. They are added to concrete to
concrete at same w/c ratio. increase the rate of early strength
development.
6) For same workability, they produce
usage of lower w/c ratio. c. They permit early removal of
formwork.
7) It also permits reduction on Cement
Content too… d. They reduce required period of
curing.
e. They advance the time that a
structure can be placed in service.
f. They are used in emergency repair
work.
Action of Retarders:
Action of Air – entraining
a) They are also called as Retarding
Admixtures:
Plasticizers.
I. One of the most important
b) Retarders are mixed with plasticizers
advancements made in concrete
to form Retarding Plasticizers for
technology was the discovery of
commercial purposes.
air entrained concrete.
c) These are used in RMC for retaining
II. Air entraining agents are
the slump loss during high
considered as FIFTH
temperature, long transportation, to
INGREDIENT in concrete
avoid construction or cold joints.
making.
III. They occupy 85% of concrete
manufactured in America
contains one or other type of air
entraining agent.
IV. Entrained air and Entrapped air
are different groups in Air
entraining admixtures.
Action of Accelerators:

5. V. Natural wood resins, animal and a. A gas forming agent is a chemical
vegetable oils, alkali salts, resin admixture such as aluminium
acids, sodium salts of petroleum powder.
sulphonic acids are types of air
entraining admixtures. b. It reacts with the hydroxide produced
in hydration of cement to produce
Action of Mineral Admixtures: minute bubbles of hydrogen gas.
i. These are also called as Puzzolanic c. Action of Aluminium powder causes
materials. a slight expansion in plastic concrete
or mortar and this reduces
ii. Puzzolona addition in concrete settlement.
improves increases the water
tightness, reduce the alkali Action of Workability Agents:
aggregate reaction, and improves
extensibility, workability and lower 1. Workability is most important
costs. characteristic of concrete.
iii. Puzzolanic materials are siliceous or 2. Finely divided materials,
siliceous and aluminous materials plasticizers, super plasticizers, air
with out cementitious values. entraining agents are used as
workability agents.
iv. Clay and Shales, Opalinc Cherts are
Natural Puzzolonas. 3. The property of concrete which is
placed and compacted 100%
v. Fly ashes, Rice Husk ash, Surkhi without air voids is called
are Artificial Puzzolonas. Workability.
Action of DP and WP Admixtures:
A. Important requirement of concrete is
that it should be impervious to water
when subjected to pressure of water
on one side and
B. Absorption of surface water by
capillary action. Action of Bonding Agents:
C. Vegetable oils, fats, waxes are some 1. These are water emulsions of
kind of water proofing admixtures. several organic materials that are
D. Calcium or Ammonium stearate or used to grout for application to an
oleate will mainly act as water old concrete surface just prior to
repelling materials. patching.
E. Butyl Stearate is superior to soap as 2. Natural Rubber, Synthetic Rubber,,
water repellent material in concrete. Poly vinyl Chloride are Bonding
Agents.
Action of Gas Forming Agents:

6. 3. They are added to 5 to 20% of 2. Sodium Benzoate was used as
weight of cement. Corrosion Inhibiting Agents.
3. 2% of Sodium Benzoate is used in
water.
4. Calcium Lignosulphate decreased
rate of corrosion of steel in concrete.
Action of Colouring Admixtures:
I. The requirements of suitable
admixtures include :
1. Colour fastness when exposed
to sunlight, Effect of Compounds on Properties of
2. Chemical stability in presence Concrete:
of alkalinity produced in set Workability:
cement,
 Generally, concrete is to have more
3. No adverse effect on setting workability, if water content in
time and strength. concrete is reduced, usually its
II. They are used to give attractive workability is lost which is not
colours and even pleasant good
colours.  So, in such cases, we use
III. They are used in RMC to arrest plasticizer which not only reduces
possible cracks and craziness in water content in w/c ratio up to
floor. 15% of original content but also
increases workability even with
that less quantity of water.
 Super plasticizers, they even
reduce water content up to 30%,
which is double of plasticizers. So,
it is mostly used in many
constructions where water scarcity
is a big problem.
 OPC sets at a time of even 5
Action of Corrosion Inhibiting Agents: minutes, which is not wanted in
many number of constructions. So
1. The problem of corrosion of to retard the initial setting time,
reinforcement is universal problem. some of compounds such as
Retarders are used. The main use

7. of them is to retard the Initial used in Constructions as they give
Setting Time of concrete. good strength.
 Accelerators are also used to  The better the workability of
accelerate Initial and also Final concrete, the better the strength of
Setting Time of Concrete. concrete, so workability agents
play role in improving strength of
 Air entraining admixtures are very concrete.
important in concrete, so, they are
considered as Fifth Ingredient in  Without proper bond between the
Concrete components of concrete, the
concrete cannot with stand loads,
 Workability agents are mainly to give more strength Bonding
useful to give better workability for Agents are necessary to be used.
concretes.
 Colouring admixtures does not
 Bonding agents are mainly used to give any strength to concrete but
bring a good bond between they can give pleasant colours to
components of concrete. concrete.
 Colouring and Corrosion Inhibiting  Corrosion inhibiting agents are
Admixtures are mainly useful to useful in preventing corrosion to
give pleasant colours and also to reinforcements in concrete.
reduce corrosion effects on
Reinforcements in Concrete.
On Strength: On Durability:
 Plasticizers not only reduces w/c  As strength increases, durability
ratio but also gives good strength. also increases. So all the above
discussed compounds have good
 Super plasticizers are not only high durability as far as they are used in
range water reducers they also give a limited and in calculated manner.
more strength than general w/c
ratio concrete.  Though, plasticizers affect PVC
coatings, but not so much, but
 Accelerators are mainly used to get these play a vital role in improving
Early Strength of Concrete. strength, durability and workability
of concrete.
 Retarders are also useful to gain
strength but in late time. Uses:
 Air entraining admixtures are  While constructing bridges, piers
mainly considered as Fifth supporting bridges must be strong
Ingredient in Concrete, so it also enough to support and carry loads
gives good strength to concrete. coming on to it.
 Mineral admixtures are Puzzolanic  So, to have better workability and
materials which includes Fly ash, strength, we use some of
Rice Husk which are presently

8. compounds such as Plasticizers,  To give pleasant Colour to
Super plasticizers, Accelerators, concrete, we add colouring agents.
Retarders.
 To give good strength,
 Piers are to constructed inside reinforcements should not be
water. If any concrete structure is corroded. To prevent that, we use
placed in water, it collapses. corrosion inhibiting agents.
 To prevent such collapses, we use  To have better workability, we use
ACCELERATORS, which are workability agents which are used
wonderful invention in Civil in many cases such as construction
Engineering. of underground works, piers.
 Accelerators, they accelerate the  Concrete Curing Compounds,
initial setting time of concrete to 1
to 1.5 minutes. So, as if pour Mould Releasing Agents, Non –
concrete inside piers, the concrete shrink high Strength Grout, Surface
starts to set inside the hollow Retarders,
columns and pier is constructed
Ready to use Plaster, Guniting Aid
inside water.
are Protective Coatings are many types
 If the construction is done at a of construction chemicals which are
business site, it is almost used at construction site which give
impossible to mix concrete at site better workability and also prevent
itself. cracks and problems coming in future.
 So, we have to transport concrete
from manufacturing industries.
 As they travel from industries to
site, the concrete may set. So to
retard the setting time of concrete,
Retarders are used.
 Not only in such cases, when
concrete is to be sent at very lower
depths, at about, 600 – 700 feet
below, they due to heat evolving
there, concrete may loose water
and they may set.
 To prevent Initial Setting time, we
use Retarders.
 To have a good bond between
components of concrete, we use
Bonding Agents.

9. Conclusion:
There is no particular
conclusion for Advances in
Concrete Technology, since
technology is increasing day by
day.
But as Civil Engineers we have
to concentrate on Economy and
Durability of Structures.
Since:
WE ARE THE ONLY HOPES
OF TOMMORROW’S
WONDERFUL
CONSTRUCTIONS.
These are some of constructions
built by using above mentioned
compounds.