Vacuum concrete is the type of concrete in which the excess water is removed for improving concrete strength. The water is removed by use of vacuum mats connected to a vacuum pump. The main aim of this technique is to extract extra water from concrete surface using vacuum dewatering.

1. BY
Balamurali.k
18tpcv006

2. VACUUM CONCRETE
 Vacuum concrete is the type of concrete in which
the excess water is removed for improving concrete
strength.
 The water is removed by use of vacuum mats
connected to a vacuum pump.
 The main aim of this technique is to extract extra
water from concrete surface using vacuum
dewatering.

4. PROCEDURE
 In the usual manner, a concrete mix with
good workability is pace in the form-works.
 As fresh concrete contains continues the system of
water-filled channels, the application of a vacuum to
the surface concrete results in a large amount of a
vacuum to the surface of the concrete.
 This results in a large amount of water being
extracted from a certain depth of the concrete.

5.  The vacuum is applied through porous mats connected
to a vacuum pump.
 The final water cement ratio before setting is thus
reduced and as this ration largely controls the
strength, vacuum concrete has a higher strength and
also density a lower permeability and a greater
durability.

7. NEEDS
 The chemical reaction of cement with water
requires a water-cement ratio of less than 0.38
 Workability is also important for concrete
 Workability and high strength don’t go together
as their requirements are contradictory to each
other
 Vacuum concrete is the effective technique used to
overcome this contradiction

8. COMPONENTS
 There is a marked reduction in effective water-
cement ratio and the performance of concrete
improves drastically.
 This improvement is more on the surface.
1) Vacuum pump
2) Water separator
3) Filtering pad
4) Screed board vibrator

9. VACUUM PUMP
 A vacuum pump is a device
that removes gas molecules
from a sealed volume in order
to leave behind a partial
vacuum.
 Vacuum pump are categorized
as gas transfer pumps and gas
binding or capture pumps.

10. WATER SEPARATOR
 Water separators are
mechanical separators that are
typically installed downstream
of the air compressor tanks.
 Depending on compressed air
temperature, water separators
are able to remove 40-60% of
water

11. FILTERING PAD
 Filtering pad should have
minimum dimension of 90cm x
60cm.
 Filter pads are placed on the fresh
concrete

12. SCREED BOARD VIBRATOR
 Screed vibrator is used for
the levelling as well
compaction of concrete
 It consists of high quality
steel bar
 Special water protective
vibrator motor is mounted
in the centre which
produces 1830N
centrifugal force which is
most ideal

13. VACUUM DEWATERING PROCESS

14. VACUUM DEWATERING OF CONCRETE

15. LAYOUT OF VACUUM DEWATERED
FLOORING

16. ADVANTAGES
 Both workability and high strength are achieved
 Reduction in water-cement ratio may increase the
compressive strength by 10-50% and lowers the
permeability
 It enhances the wear resistance of concrete surface
 The surface is plain and smooth due to reduced
shrinkage
 The formwork can be removed early

17. DISADVANTAGES
 High initial cost
 Need trained labour
 Need specific equipment
 Need power consumption
 The porosity of concrete allows water, oil and
grease to seep through, consequently weakening
the concrete

18. APPLICATIONS
Industrial
floor sheds
like cold
storages
Hydro
power
plants
Bridges
ports and
harbour
Cooling
towers

19. THANK YOU