Concrete Technology

1. Unit - 3
CONCRETE

2. What is Concrete?
o an artificial stone-like mass, is the composite material
that is created by mixing binding material (cement or
lime) along with the aggregate (Sand, gravel, stone,
brick chips, etc.), water, admixtures, etc in specific
proportions. The strength and quality are dependent
on the mixing proportions.
o The formula for producing concrete from its
ingredients can be presented in the following
equation:
• Concrete = Binding Material + Fine & Coarse
Aggregate + Water + Admixture (optional)

4. PROPERTIES OF THE CONCRETE
Mechanical strength,
Durability
Workability
Porosity and density
Fire resistance

5. TYPES OF CONCRETE USED IN THE
INDUSTRY
• Normal concrete
• High strength concrete
• High performance concrete
• Self compacting concrete
• Pervious concrete
• Light weight concrete
• Aqua concrete
• Ready Mix Concrete

6. GRADES OF CONCRETE
• The process of selecting the proper grade of concrete is important to
arrive at an economical and durable material.
• In this manner the grade of the concrete is taking a big role here.
Generally the mix designs are prepared based on the requirement of
strength, workability and durability for the project specifications.
• The grade is generally denoted as M30, which means the
compressive strength of the concrete M30 is 30 MPa.
• The grade of the concrete is very much likely depending on the mix
proportion of its component other than the workmanship at the site.
Each and every component of the concrete playing a major role in
the function.

8. The stages of concrete production
Batching (measurement) of materials.
Mixing.
Transporting.
Placing.
Compacting.
Curing.
Finishing.

9. BACHING OF MATERIALS Volume Batching
 Weigh Batching
MIXING
1. Hand Mixing
2. Machine Mixing
i. Tilting Mixer
i. Non-tilting Mixer
i. Reversing Drum Mixer
i. Pan-type or Stirring Mixer
i. Transit Mixer
TRANSPORTING i. Mortar Pan
ii. Wheel Barrow
iii. Chutes
iv. Dumper
v. Bucket and Ropeway
vi. Belt conveyor
vii. Skip and Hoist

10. The Types of Concrete
1. Normal Strength Concrete. This concrete combines all the
basic ingredients — concrete, sand and aggregate — using
the 1:2:4 ratio. ...
2. Plain or Ordinary Concrete. ...
3. Reinforced Concrete. ...
4. Prestressed Concrete. ...
5. Precast Concrete. ...
6. Lightweight Concrete. ...
7. High-Density Concrete. ...
8. Air-Entrained Concrete

11. TEST CARRIED OUT ON CONCRETES
Tests on Fresh Concrete Tests on Hardened Concrete
1. Workability Tests
i. Vee-bee consistometer test,
ii. Compaction factor test,
iii. Slump test
1. Compressive strength
2. Air content
i. Measurement of Air Content in Concrete
by Pressure Air Method
2. Tensile strength
3. Setting Time
i. Final Setting Time,
ii. Initial Setting Time
3.Modulus of elasticity

12. READY MIX CONCRETE
• Ready Mix Concrete is a ready-to-use material which is a
mixture of Cement, Sand, Aggregate and Water.
• RMC is a type of Concrete which is mixed in a batching plant
according to the specification of the customer and delivered to
the site by the use of transit mixer as it is away from the
construction site.

13. Advantage of RMC
 Better quality is produced in lesser time.
 Wastage of basic material is avoided.
 Labour association with production of
concrete is eliminated.
 Time required is greatly reduced.
 Noise and dust pollution at site is reduced.

14. RMC production

15. TYPES OF READY MIX CONCRETE
 Transit mixed concrete
 Shrink mixed concrete
 Central mixed concrete

16. Transit mixed concrete
 It is also called dry batched concrete because all the
basic ingredients including water are charged directly into
the truck mixer.
Shrink mixed concrete
 The concrete is partially mixed in the plant mixer and then
balance mixing is done in the truck mounted drum mixer
during transit time.
 The amount of mixing in transit mixer depends upon the
extent of mixing done in the central mixing plant.
 Tests should be conducted to establish the requirement of
mixing the drum mixer.

17. Central Mixed Concrete
 It is also called central batching plant where the concrete is
thoroughly mixed before loading into the truck mixer.
 Sometimes the plant is also referred as wet-batch or pre-mix plants.
While transporting the concrete, the truck mixer acts as agitator only.
 when workability requirement is low or the lead is less, non-
agitating units or dump trucks can also be used.

18. ADVANTAGES OF READY MIXED CONCRETE
 Cement is saved and the dust caused is reduced as
ready mix concrete make use of bulk concrete
instead of bags of cement.
 Cement saving will conserve the energy and the
resources.
 Less consumption result in less production of
cement hence less environmental pollution.
 More durable structure is obtained thus increasing
the service life and saving the life cycle costs.
 Small or large quantities of concrete as per the
specification is delivered timely at the site.

19. Disadvantages of Ready Mixed Concrete
 The transit time from the time of preparation of
concrete to the delivery site, will result in loss of
workability.
 This will demand for additional water or admixtures to
maintain the workability as per the specification.
construction.
 Traffic during the transit of concrete can result in setting
of concrete
 This will hence require addition of admixtures to delay
the setting period. But unexpected traffic is a great
problem.
 The formwork and placing arrangement must be
improper...

20. THANK YOU