Transportation of Concrete - Notes for Civil engineering Students

Presentation on Transportation of Concrete in field.

1. KAS-2012 1
TRANSPORTATION OF
CONCRETE
K A Shah
B.Sc.(Civil Engg.) MSc.(Environment Engg.)
Ex-GM-MNC
Guest Faculty- CTE

2. KAS-2012 2
TRANSPORTATION OF CONCRETE
Precaution in concrete transportation:
Homogeneity of conc. Mass is maintained
 Movement of hand trolly or truck on rough
road surface makes vibrations
This results in deposition of heavy
aggregates at bottom of truck
Water & cement slurry comes on top.

3. KAS-2012 3
METHODS OF TRANSPORTATION
1.Mortar Pan
2.Wheel barrow
3.Truck Mixer & dumpers
4.Crane, Bucket & rope way
5.Belt conveyors
6.Chutes
7.Skip & hoist
8.Transit Mixer
9.Pump & pipeline
10.Helicopter

4. KAS-2012 4
MORTAR PAN
Common method in India
More labour required
Segregation of concrete is less
Greater surface area of concrete is
exposed to sun, concrete dries.

5. KAS-2012 5
WHEEL BARROW
When transportation of concrete is at
ground level.
 Movement of wheel on rough road
surface, segregates concrete.
 Some wheel barrows have pneumatic
wheel to reduce vibration

6. KAS-2012 6
CRANE
Used for transporting concrete above
ground level.
For high rise buildings.
Cranes are fast
 Can move horizontally & vertically
Concrete in skip discharge from bottom
In bucket concrete is discharged by tilting.

7. KAS-2012 7
CONCRETE TRANSPORT BY CRANE-
VIDEO
Pouring Concrete-Cement Truck-Crane-Construction Excavation Site.flv

8. KAS-2012 8
BUCKET & ROPEWAY
Use for construction in:
Valley
Bridge pier in river
Dam
Advantage:
Concrete is not exposed to sun or air & no
loss of water.

9. KAS-2012 9
ROPEWAY-VIDEO
Package

10. KAS-2012 10
Truck Mixer & dumpers
Used for large concrete works.
Can travel any part of site.
Dumpers - 2-3 M
3
Capacity
Trucks – 4 M
3
Capacity
Bottom surface of truck is kept wet
Top of truck is covered to prevent
evaporation

11. KAS-2012 11
BELT CONVEYOR-VIDEO
Package

12. KAS-2012 12
BELT CONVEYORS
Limited use in construction
Advantages:
Can transport large volume
Very quick
Can go where access is limited
Disadvantages :
 On steep slope concrete segregates.
 Exposed to sun for long time.

13. KAS-2012 13
CHUTE
For transporting from ground level to lower
level. (basement etc).
Used where labour can not reach due to
less space in trench etc.
Made of metal
Slope should not be < 1 vertical : 2.5
horizontal.

14. KAS-2012 14
SKIP & HOIST -VIDEO
Package

15. KAS-2012 15
SKIP & HOIST
Labour can go upto 3rd or 4th floors.
So skip is used for transport vertically up
(in multistory building).
Skip travels on vertical rail.
Skip can discharge manually or
automatically.

16. KAS-2012 16
TRANSIT MIXER

17. KAS-2012 17
TRANSIT MIXER
Used for long distance travel in RMC plant.
Concrete is continuously agitated in truck drum
(2 – 6 rpm).
Also transported mix in dry condition and water
is added on reaching the destination.
Wet Mix in truck must reach site in 1- 1.5 hours.
Pumps are also fitted on truck mixer to
discharge concrete.

18. KAS-2012 18
PUMPS & PIPELINE
Most popular method
Reliable & good quality pumps are used.
Mostly operated by diesel.
Concrete is placed in collecting hopper.
Rotating blades in hopper pushes concrete
towards pipe.
Vacume in hose pipe (600 mm Hg)
Rotating rollers in pump chambers squeeze the
concrete in pipe and flow of concrete is started.
 Concrete is discharged from other end of hose
pipe.
Concrete can be pumped upto 400 m height and
2000 m distance.

19. KAS-2012 19
SECTION OF PUMP

20. KAS-2012 20
PIPELINE
Pipeline should :
Have correct diameter as per pump
pressure. (generally 125 mm)
Have sufficient thickness
Good couplings
Poor pipeline can cause blockage.

21. KAS-2012 21
PIPELINE
Thumb rule : For 30 M
3
/hr concrete and
200 m length, dia should be 100 mm.
Length > 500 m then dia = 150 mm.
Dia = 3 to 4 times the size of aggregate
Leaky pipe & coupling result in escape of
water /air & finally block the concrete.
Vertical pipe should good otherwise
difficult to change at height.
Pump is kept at distance from building
about 15 % of vertical length.

22. KAS-2012 22
CONCRETE FLOW IN PIPE

23. KAS-2012 23
PUMPABLE CONCRETE
Concrete which can be pushed through a pipeline is
called pumpable concrete.
Friction between pipe wall and concrete is less.
Concrete flows in the form of plug which is separated
from pipe wall by a thin layer of lubricating cement paste.
Flow resistant must be < pump pressure.
If the concrete is more wet then water comes out of mix
which makes more resistance to flow.
Stiff and also very wet concrete is not pumpable.

24. KAS-2012 24
Design of pumpable concrete
Concrete Mix is so designed that all material remain
together.
Mix must make redial movement of grout to maintain
lubricating paste.
Mix should be deformed at bends
Cement & fine particles (0.25 mm size) are important for
good flow.
350 to 400 Kg/ M
3
of fine particles are necessary for flow.
Slump of pumpable concrete is above 75 mm.

25. KAS-2012 25
PROBLEMS IN PUMPING
Blockage in pipe
Pipe should be cleaned after each day
operation
Blockage can be cleaned by forward-
backward pumping.
Tapping pipe with hammer
Clean pipe with rod or sponge ball pushed
by compressed air.

26. KAS-2012 26
THANKS