Vacuum dewatering is a process that removes excess water from freshly poured concrete to achieve an ideal water-cement ratio and improved properties. Concrete is poured and a vacuum pump then removes 15-25% of the water through a suction mat and filter pads. This results in higher strength, less cracking and shrinkage, improved abrasion resistance, and a smooth, level surface. Vacuum dewatering is commonly used for industrial and commercial floors that require high durability.

1. VACUUM DEWATERING
CONCRETE FLOORING
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PRESENTED BY
AGLAIA

2. WHAT IS VACUUM DEWATERED
FLOORS..???
 Concrete is being the most versatile of flooring material
has been in use for a long time
 To overcome the deficiencies of concrete flooring, a
system was devised to improve the properties of such
concrete floors.
 This system was “VACUUM DEWATERED FLOORS”
 It permits to add much water for workable and easily
pourable.
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3.  The addition of water reduces the strength of the
concrete.
 This system removes the excess water and maintain an
ideal water/cement ratio.
 This system will maintain all the properties of the
concrete.
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4. VACUUM DE-WATERED CONCRETE FLOOR
 Concrete of the required grade such as M20, M25 etc
are poured over the PCC and reinforcement bars as
per design.
 Vacuum de-watering (VDF) is a process by which
excess water is removed in a controlled fashion by
applying vacuum
 The concrete is then power-trowelled to obtain a
smooth and dense concrete
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5.  VDF floors are known to provide a good concrete floor
and is known to achieve strength earlier than a control
concrete
 However, contrary to the popular belief, for a specified
design mix, the compressive strength cannot be more
than the targeted strength.
 Due to controlled water-removal as well as power-
trowelling, the surface is quite dense and levelled and
hence is expected to provide a better abrasion
resistance than a non-VDF concrete floor.
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6. FUNDAMENTALS FOR
DEVELOPMENT OF V D F
 Value for money
 Level floor, high flatness accuracy
 Improve wear resistance
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7. NEED OF V D F
 The mixing water added to a concrete mix exceeds
the amount of water required to fully hydrate the
cement constituent.
 The additional water functions as a lubrication
medium to allow mixing, placing and consolidation.
 In conventional concreting practice, an important
challenge is the prevention or limiting of evaporation
of mixing water out of the freshly placed concrete.
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8.  The uncontrolled removal of water from the concrete
matrix can result in adverse effects such as plastic
shrinkage cracking.
 Excessive bleeding of concrete can caused for wear
resistance.
 Thus the durability and service life of the flooring
element is in question.
 In hot and windy conditions it produce quality, durable
concrete.
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9. INSTRUMENTS USED IN V D F
Vacuum de-watering Pump
 Vacuum Pump is used to reduce water content in the
concrete by 15-25%.
 It is used to suck all the air bubbles that may have
trapped during the laying of the concrete.
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Fig. 1 Vacuum de-watering Pump
(Source: www.skylarkrebar.in)

10. FLOATER MACHINE
 Floating & Troweling take place right after dewatering
 This makes the cement more compact and enabling to
generate a very smooth finish.
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Fig. 2 Floater Machine
Source: Google images

11. TREMIX SKIN
 Suction Mat of special grade multilayered polymer
sheets ensure sufficient cross-sectional area to
squeeze out and remove excess water from the
concrete.
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Fig.3 Tremix Skin
Source:constructor.org

12. DOUBLE BEAM SCREED VIBRATOR
 Double beam screed vibrator consists of a Beam unit
and a vibrator unit
 Double beam screed vibrator is used to vibrate the
concrete to give a compact and levelled surface
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Fig. 4 Vacuum de-watering Pump
(Source: www.skylarkrebar.in)

13. VACUUM DEWATERING PROCESS
 Preparation of sub base.
 Divide floor area into panels.
 Preparation of framework using steel channels.
 Laying down of steel bars of specified size.
 Mix design of concrete.
 Placing of concrete and compacting.
 The vacuum dewatering process removes surplus
water present in the concrete. 13
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14.  This is done using the Vacuum Equipment comprising of
Suction Mat Top Cover, Filter pads and Vacuum Pump.
 This process starts immediately after surface vibration.
 Filter pads are placed on the fresh concrete leaving about
4 inches of fresh concrete exposed on all sides.
 The top cover is then placed on the filter pads and rolled
out till it covers the strips of exposed concrete on all sides.
 The top cover is then connected to the vacuum pump
through a suction hose and the pump is started.
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15.  Vacuum is immediately created between the filter pads and the
top cover.
 Atmospheric pressure compresses the concrete and the surplus
water is squeezed out.
 This process lowers the water content in the concrete by 15 –
25%.
 The dewatering operation takes approximately 1.5 – 2 minutes
per centimetre thickness of the floor.
 The dewatered concrete is compacted and dried to such an
extent that is possible to walk on it without leaving any foot
prints.
 This is the indication of concrete being properly dewatered and
ready for finishing.
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16. The filter pads are placed so that there will be a
sealing edge around the entire filter pad
surface
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Fig.5 Filler Pads
(Source: www.skylarkrebar.in)

17. Fig.6 The top cover is unrolled over the filter pads.
(Source: www.skylarkrebar.in)
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18. Fig. 7The top cover of filter pads is connected to the
suction hose of the vacuum pump.
(Source: www.skylarkrebar.in)
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19. While vacuum is on , the surface that has
already been vacuum dewatered is floated
with a power trowel fitted with a disc.
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20. TREMIX VACUUM SYSTEM STAGES
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Fig. 8 Stage of tremic vaccum system
(Source: www.skylarkrebar.in)

21. ADVANTAGES OF V D F
 Reduction in W/C ratio leads to early setting and
high strength.
 It removes the excess water of the concrete & an
ideal W/C ratio can be achieved.
 Increase in compressive strength of concrete by 40
– 70%.
 The surface hardness of the slab increase by
130%.
 Water absorption is reduced enormously.
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22.  Minimum dusts.
 Level floor, high flatness accuracy.
 Minimized crack formation, shrinkage reduced by 50%.
 Improved wear resistance.
 Elimination or minimization of overtime.
 High and early strength, minimize damage to newly
cast floors.
 Void – free and Denser concrete.
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23. APPLICATIONS OF V D F
Warehouses
Roads, Sports Courts
Cellars, Parking Areas
Production Areas,
Industrial Shop floors
Base floor for Resinious floors - Epoxy, PU,Mat,
Carpets & Wooden Floors
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24. CONCLUSION
 Vacuum Dewatering process is very important
modern construction work in the context of
economy, facility, modern technology and comfort.
 It is very useful for special purpose projects like for
the use of wear house, parking area, industrial
flooring like flooring of large area.
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25. THANK YOU
For more…. Mail to
aglaiaconnect2018@gmail.com