lorries, trucks, dumpers, elevators, conveyors, hoist, cranes, concrete mixers, pumps

2.  Transport or transportation is the movement of people,
animals and goods from one location to another.
 Modes of transport include air, rail, road, water, cable, pipeline
and space. The field can be divided into infrastructure, vehicles
and operations.
 Transport is important since it enables trade between people,
which in turn establishes civilizations.
 Transport infrastructure consists of the fixed installations
necessary for transport, including roads, railways, airways,
waterways, canals and pipelines and terminals such
as airports, railway stations, bus stations, etc.

3.  A truck is a motor vehicle for transporting goods.
 Unlike automobiles, which usually have a unibody
construction, most trucks (with the exception of the car-like
minivan) are built around a strong frame called a chassis.
 They come in all sizes, from the automobile-sized pickup truck
to towering off-road mining trucks or heavy highway semi-trailers.
 A truck (US, CA and AU) or
lorry (UK and Ireland) is a motor
vehicle designed to transport goods.
 Hauling is the activity of transporting
goods by truck. The trucks are hauling
units that provide relatively low hauling
cost because of their high travel speeds.

4. LIGHT TRUCKS
MEDIUM TRUCKS VERY HEAVY TRUCKS
HEAVY TRUCKS

5.  A dump truck is
a truck used for transporting
loose material (such
as sand, gravel or dirt)
for construction.
 Typical dump truck is
equipped with a hydraulically
operated open-box bed hinged
at the rear.

6.  Standard dump truck
 Side dump truck
 Off- road dump truck
 Articulated dump truck
 Transfer dump truck
 Super dump truck
 Semi trailer dump truck
 Double trailer bottom truck

7.  A standard dump truck is a full truck chassis with a dump body
mounted to the frame.
 The dump body is raised by a hydraulic ramp mounted forward of
the front bulkhead, between the truck cab and the dump body.

8.  A side dump truck
consists of a 3 – axle
tractor pulling a 2 – axle
semi trailer .
 It has hydraulic rams
which tilt the dump body
onto its side , spilling the
material to either the left or
right side of the trailer.
 The key advantages of
the side dump are that it
allows rapid unloading and
can carry more weight.

9.  Off – road dump trucks
more closely resemble
heavy construction
equipment or engineering
vehicles.
 They are used strictly off –
road for mining and heavy
dirt hauling jobs. The term
‘dump’ truck is not generally
used by the mining industry.

10. An articulated dump truck has a hinge
between the cab and the dump box,
but is distinct from semi trailer trucks
in the cab is a permanent fixture , not
a severable vehicle. This vehicle is
highly adaptable to rough terrain.
A transfer dump truck is a standard
dump truck which pulls a separate
trailer which can be loaded with
aggregate (gravel, sand, asphalt,
etc.)

11. SEMI TRAILER BOTTOM DUMP TRUCK
A semi bottom dump (or "belly dump") is a 3-
axle tractor pulling a 2-axle trailer with a clam
shell type dump gate in
the belly of the trailer.
The key advantage of a semi bottom dump is its
ability to lay material in a wind row (a linear
heap).
SUPER DUMP TRUCK:
A super dump is similar to a standard
dump truck except it is equipped with
extra axles to carry more weight .

12. DOUBLE AND TRIPLE TRAILOR BOTTOM DUMP TRUCK
 Double and triple bottom dumps consist of a 2-axle tractor pulling
one single-axle semi-trailer and an additional full trailer.
 These dump trucks allow the driver to lay material in wind rows
without ever leaving the cab or even stopping the truck.
 The main disadvantage is the difficulty in backing double and triple
units in reverse.

13. •Transporting material from one place to another over a stationary structure.
•Caries material in continuous stream with its distinct feature such as endless
chain or belt.
•Can be done horizontally, vertically or inclined.
•When the equipment does horizontal conveying, it is known as conveyor
and when it does vertical, it is known as elevator.
•Conveying are mainly used in mining, construction and in some of the
industries.

14. Conveyors are a piece of plant moving mainly in the horizontal direction.
 Conveyors are used mainly for transporting aggregates and concrete and
generally considered only in large sites where there may be a large
concrete mixing complex.
 These are the equipment to move material over a fixed path between
specific points.
These are used in mining , heavy & light industry , food & beverage
processing , agriculture , construction projects.

15. BELT CONVEYORS:
•Used when large quantities of materials have to be conveyed over long distances at
fast speed.
•It consists of a belt running over a pair of end drums or pulleys and supported at
regular intervals by a series of rollers called idlers.
•These idlers are supported on a conveyor frame.
•The middle sag provided in the belt prevent the spilling of material.
•Generally, rubber is most commonly used as conveyor belt.

16. ADVANTAGES OF BELT CONVEYOR
• It can handle light as well as heavy materials, dry or wet, fine or coarse etc.
• It can and for distances to convey several thousand tons of material per hour
and for distances of distances of several kilometers.
• It can carry material horizontally or inclined.
• It is lighter in weight then other conveyors.
• It gives controlled discharge of material and discharge can be controlled by the
speed of the belt.
There are two types of belt conveyor:
1. Horizontal belt conveyor
2. Inclined belt conveyor

17. HORIZONTAL BELT CONVEYOR
•The conveyor belt system consists of a continuous moving belt that carries
materials or packages from one place to another.
•In this system the conveyor belt moves in horizontal direction.

18. INCLINED BELT CONVEYOR
•It is designed for steep excavation work, it is ideal for basement excavating, utility
contracting and other earth and material applications.
•The belt buckets have a high capacity to eliminate material rollback at steep inclines.
IN CASE OF INCLINED BELT CONVEYOR
•It can move gravel, mud, dirt, silt etc.
•From 0º to 70º
•It is used for digging basements, general excavation and construction.
• It fits in small window openings, manhole covers, etc.

19. SCREW CONVEYOR
•Screw conveyors are of simple, relatively low cost
construction compared to other conveyor systems.
•Screw conveying systems consist of a helical flight
fastened around a pipe or solid shaft, mounted
within a tubular or U-shaped trough
•It permits intermediate discharge of the material at
several points.
• It is a bulk material handling unit.
• It is suitable for the conveying of granular or
powder material and liquids.
•It can perform horizontal, inclined(as an efficient
way to move semi-solid materials) and vertical
conveying.
• The angle of inclination of inclined conveyors is
usually 10° to 20°.
•The conveying length is 2 meters to 70 meters.
Screw dia. 100 to 900 mm.

20. Uses-
•They are used for handling of dry & semi liquid material for Mixing and Blending
of material.
• Used in grain & oil, feed, food, metallurgy, mine, plastic, chemical engineering,
building material, medicine industries.
• Used for extraction, filling and transporting raw material like cement, concrete,
sludge and various aggregates.
•to transfer crushed materials from one place to another.
Some of the many advantages of a screw conveyor are:
•Economical
•Low maintenance
•Totally enclosed
•Multiple discharge locations
•Easy to install
•Quiet operation
•Can operate on inclines

21. BUCKET ELEVATOR
•Bucket elevators are designed to move flowing powders or bulk
solids.
•Bucket elevators use an endless belt or chain and have a series of
•buckets attached to it.
•Bulk material is spread into an inlet hopper.
•Buckets (or cups) dig into the material and convey it up and over
• the head sprocket/pulley, and then throw the material
•out a discharge throat.
•The plastic buckets are truly interlocking and never separate.
•This equipment is mainly used for the lift conveying of
•the materials at the lower position to the upper specified position.
There are three types of bucket elevator:
1. Continuous discharge bucket elevator
2. Centrifugal discharge bucket elevator
3. Positive discharge bucket elevator

23. • Buckets are mounted without any gap on a chain or
belt. This type of elevator often used for handling
larger lumps of material that may be difficult to
convey by centrifugal type.
• It is also called Low-Speed Gravity Discharge
Elevators and speed range of 30 to 50 m/min.
• This type of elevator suitable for fragile, fluffy or
pulverised materials.
• It can operate in the vertical or inclined condition.
Application:
1. Lime,
2. Cement and
3. Dry chemicals
CONTINUOUS BUCKET ELEVATOR

24. ADVANTAGES
•It is ideal for transporting in factories without
damaging or breaking the product.
• The gentlest possible handling of product
with the least spillage, lowest possible
maintenance, and the quietest operation.

25. CENTRIFUGAL BUCKET ELEVATORS
Applications:
Grain, Coal, Sand, Clay, Sugar and Dry Chemicals.
•Centrifugal discharge for small grain.
•They operate at high speeds, which throw the materials out
the buckets into discharge throats by centrifugal force.
•In a centrifugal discharge elevator, buckets are fixed on to
belt or chain at regular pitch to avoid interference in loading
and discharge.
•This type of elevators is mostly vertical in operation and
can handle practically any free flowing fine or small lumpy
materials.
•Speed range is 70 to 125 m/min.
•Usually lump size larger than 50mm are not used for these
types of elevators. On the other hand, it is also necessary to
check that the materials are not finer than 200 mesh size.

26. •This type of elevators is similar to the centrifugal
discharge elevator except for two distinguishing features.
•The buckets are spaced at regular pitch and mounted on
two strands of chains, and are provided with a snub
wheel under the head sprockets to ensure inverting of
the bucket for complete discharge.
•The speed of the bucket is slow in the range of 35 – 40
m/min.
•This type of elevators is used for handling light, fluffy,
dusty and sticky materials. The feeding is done by the
scooping or digging by the buckets.
POSITIVE DISCHARGE ELEVATORS

27. CONSTRUCTION ELEVATOR
•Also known as a construction hoist, temporary elevator.
•This type of elevator is commonly used for large scale construction projects.
•It is used to carry materials, and equipment quickly between the ground and higher
floors, or between floors in the middle of a structure.
•The construction elevator is made up of either one or two cars (cages) which travel
vertically along with tower sections.
•Modern construction elevators use a motorized rack-and-pinion system that climbs the
structured sections at various speeds.
This elevator are widely used at the sites of :-
•Industrial and civil construction,
•Bridge construction,
•Underground construction,
•Large chimney construction,
•Ship industry,

28. EXPLOSION PROOF ELEVATORS
•Explosion proof elevators is used where there is a
risk of explosive gases or dusts being present.
•The drive and control units are mounted on top of
the car.
•We use a durable, reliable motor that is designed
for
outdoor use.
•All elevators are equipped with a dual-motor
system
to build an extra level of reliability and safety into
the system.

29. •The most common types of industrial elevators are hoist elevators and incline elevators.
•These types of elevators are built to carry huge amounts of weight
•Hoist elevators are operated by a pulley or series of pulleys and they can be a simple
platform or a cage in which heavy materials are moved up and down.
This type of elevators is used in :
•Construction,
•Warehouses,
•And shipyards.
HOIST ELEVATORS

30. A crane is a type of machine, generally
equipped with a hoist, wireropes
or chains, and sheaves.
 it is used to lift and lower materials and
to move them horizontally.
It is mainly used for lifting heavy things
and transporting them to other places.
Cranes are commonly employed in
the transport industry for the loading and
unloading of freight, in the construction
industry for the movement of materials
and in the manufacturing industry for the
assembling of heavy equipment.

31. OVERHEAD CRANE-
MOBILE CRANE
oTRUCK-MOUNTED CRANE
oSIDELIFT CRANE
oROUGH TERRAIN CRANE
o ALL TERRAIN CRANE
oPICK AND CARRY CRANE
oCARRY DECK CRANE
oTELESCOPIC HANDLER CRANE
o CRAWLER CRANE
o RAILROAD CRANE
o FLOATING CRANE
Instead of the whole crane moving, only the
hoist / trolley assembly moves in one
direction along one or two fixed beams
Often mounted along the side walls or on
elevated columns in the assembly area of
factory.
TOWER CRANE(FIXED)
oSELF-ERECTING CRANE
oTELESCOPIC CRANE
oHAMMERHEAD CRANE
o LEVEL LUFFING CRANE
oGANTRY CRANE
o DECK CRANE
o JIB CRANE
o BULK-HANDLING CRANE
oLOADER CRANE
oSTACKER CRANE

32. A MOBILE CRANE IS "A CABLE-CONTROLLED CRANE MOUNTED
ON CRAWLERS OR RUBBER-TIRED CARRIERS" OR “ a hydraulic-power crane with
a telescoping boom mounted on a truck types carriers or as a self propelled
models." They are designed to easily transport to a site and use with different types of
load and cargo with little or no setup or assembly.

33. PICK AND CARRY CRANE
CARRY DECK CRANE
A Pick and Carry Crane is similar to a mobile crane
in that is designed to travel on public roads.
Pick and Carry cranes have no stabilizer legs or
outriggers and are designed to lift the load and carry
it to its destination, within a small radius, then be
able to drive to the next job.
A carry deck crane is a small 4 wheel crane
with a 360 degree rotating boom placed right in
the centre and an operators cab located at one
end under this boom.
They Carry deck can hoist a load in a confined space and then load it on the deck
space around the cab or engine and subsequently move to another site.

34. TELESCOPIC HANDLER CRANE
Telescopic Handlers are like forklift trucks
that have a telescoping extendable boom like a
crane
These new 360 degree telescopic
handler/crane models have outriggers or
stabilizer legs that must be lowered before
lifting,
These machines are often used to handle pallets of bricks and install frame trusses on
many new building sites and they have eroded much of the work for small telescopic
truck cranes.

35. TRUCK MOUNTED CRANE
ROUGH TERRAIN CRANE
A crane mounted on a truck carrier provides
the mobility for this type of crane.
Outriggers are extended horizontally and
vertically to level and stabilize the crane
while stationary and hoisting.
A crane mounted on an undercarriage with
four rubber tires that is designed for pick-and-
carry operations and for off-road and “rough
terrain” applications.
Outriggers are used to level and stabilize
the crane for hoisting.

36. ALL TERRAIN CRANE
CRAWLER CRANE
A set of tracks called crawler that
provides stability and mobility.
A mobile crane with the necessary
equipment to travel at speed on public
roads, and on rough terrain at the job site
using all-wheel and crab steering.
Lifting loads up to 1200 metric tons.
They can move around on site and
perform each lift with little setup,
since

37. RAIL ROAD CRANE
FLOATING CRANE
A railroad crane has flanged wheels for
use on railroads.
The simplest form is a crane mounted on
a railroad car.
Floating cranes are used mainly in bridge
building and port construction.
They are also used for occasional loading
and unloading of especially heavy or
awkward loads on and off ships.

38. AREIL CRANE
SIDE LIFTING CRANE
Aerial crane or ‘Sky cranes’ usually are
helicopters designed to lift large loads.
Helicopters are able to travel to and
lift in areas that are difficult to reach by
conventional cranes.
A side lifter crane is a road-going truck or
semi-trailer, able to hoist and transport ISO
standard containers.
Container lift is done with parallel crane-
like hoists, which can lift a
container from the ground or from a railway
vehicle.

39. TOWER CRANE Fixed to the ground on a concrete slab.
 The base is then attached to the mast which
gives the crane its height. Further the mast is
attached to the slewing unit (gear and motor)
that allows the crane to rotate.
On top of the slewing unit there are three
main parts which are: the long horizontal jib
(working arm), shorter counter-jib, and the
operator's cab.

40. SELF ERECTING CRANE
TELESCOPIC CRANE
Also called self-assembling or “Kangaroo”
cranes.
lift themselves off the ground using jacks,
allowing the next section of the tower to be
inserted at ground level or lifted into place
by the partially erected crane itself.
A telescopic crane has a boom that consists of
a number of tubes fitted one inside the other.
A hydraulic or other powered mechanism
extends or retracts the tubes to increase or
decrease the total length of the boom.
 Use in rescue jobs, lifting boats in and
out of the water,

41. HAMMERHEAD CRANE
LEVEL LUFFING CRANE
The “hammerhead”, or giant cantilever,
crane is a fixed-jib crane consisting of a
steel-braced tower on which revolves a
large, horizontal, double cantilever.
the forward part of this cantilever or jib
carries the lifting trolley, the jib is extended
backwards in order to form a support for the
machinery and counter balancing weight.
Normally a crane with a hinged jib will
tend to have its hook also move up and
down as the jib moves (or luffs).
A level luffing crane is a crane of this
common design, but with an extra
mechanism to keep the hook level when
luffing.

42. GANTRY CRANE
DECK CRANE
Located on the ships and boats, these are
used for cargo operations or boat unloading
and retrieval where no shore unloading
facilities are available.
Most are diesel-hydraulic or electric-
hydraulic.
The crane frame is supported on a gantry
system with equalized beams and wheels
that run on the gantry rail, usually
perpendicular to the trolley travel direction.
Hoist in a fixed machinery house or on a
trolley that runs horizontally along rails,
usually fitted on a single beam (mono-girder)
or two beams.

43. JIB CRANE
BULK HANDLING CRANE
A jib crane is a type of crane where a
horizontal member (jib or boom),
supporting a moveable hoist, is fixed to a
wall or to a floor-mounted pillar.
Jib cranes are used in industrial
premises and on military vehicles.
Bulk-handling cranes are designed from
the outset to carry a shell grab or bucket,
rather than using a hook and a sling.
They are used for bulk cargoes,
such as coal, minerals, scrap metal etc.

44. LOADER CRANE
STACKER CRANE
The crane moves on a track in an aisle
of the warehouse.
It is used for loading/unloading
the vehicle.
 It is a hydraulically-powered
articulated arm fitted to a truck or trailer.
A crane with a forklift type mechanism
used in automated(computer controlled)
warehouses.

45. HOIST
A hoist is a device used for lifting or lowering a load by means of a drum or lift-
wheel around which rope or chain wraps. It may be manually operated, electrically
or pneumatically driven and may use chain, fiber or wire rope as its lifting
medium. The load is attached to the hoist by means of a lifting hook.
TYPES OF HOIST-
Wire Rope Hoist or Chain Hoist

46. Construction hoists Mine hoists

47. CONCRETE
Concrete is a composite construction material .

48. There are two methods of mixing concrete :-There are two method of mixing of concrete:
1. Hand mixing
2. Machine mixing
HAND MIXING :-
it is the method in which we prepare a concrete by hand with the help of tools .
It requires a lot of labor and time .
The process of mixing is completed in 6-8 mins of adding water.
This method of mixing is not good but for small work it is commonly adopted .

49. CONCRETE MIXER
The concrete mixer was invented by columbus industria.
A concrete mixer is a device that homogeneously combines cement , aggregates such as
sand , gravel stone and water to form .
THE CONCRETE MIXER PROCESS:-
•Concrete mixers come in many shapes and sizes .
•However , almost all mixers consist of a revolving drum that rotates at an even speed .
•The concrete materials are placed into this drum , along with water .
•As the drum rotates the materials become mixed together .
•Over the time , the concrete becomes thoroughly mixed , offering a mixture that delivers
a maximum uniformity .

50. MACHINE MIXING
•In large and important work concrete mixing is preferred .
•Required quantities if sand and coarse aggregates are placed in the drum of the mixer.
•4 to 5 rotations are made for dry mixing and then required quantity of cement is added
and dry mixing is made with another 4 to 5 rotations.
•Water is gradually added and drum is rotated for 2 to 3 minutes during which period it
makes about 50 rotations.
• At this stage uniform and homogeneous mix is obtained.

51. ADVANTAGES OF CONCRETE MIXER:-
•Concrete is always fresh .
•It can also save lots of time, labor and money.
•Concrete is blended homogenously , creating a much better result than mixing manually.
•There is not a chance of wastage of material.
•Faster production of concrete at the site .
•Improve concrete quality control and consistency.

52. TYPES OF CONCRETE MIXERS:
Self-loading truck concrete mixers,
Drum roller concrete mixer
Volumetric concrete mixers
Mobile volumetric batching plants
Reversing drum mixer
Pan mixer
SELF – LOADING TRUCK CONCRETE MIXER :-
•Self-Loading Concrete Truck Mixer is fitted with electronic weight batching equipment
which shows the exact weight of raw materials going into the drum and the exact
amount of concrete that is discharged.
•This allows the operator to split loads of any quantity and enables multiple deliveries.
A further advantage is that it can re-load with raw materials from any builders
merchants or satellite depot, as it has its own batching equipment, self-loading
equipment, on-board water system and auxiliary engine.
• It can be fitted to any cab/chassis, with the correct specifications, or even onto a
trailer.

53. Volumetric Concrete Mixers offer
substantial advantages over traditional
methods of concrete delivery.
•This type of construction equipment is
basically a mobile truck mixer and
batching plant rolled into one.
•All raw materials are stored in separate
compartments and these are then
metered and mixed into fresh cement
where and when it’s needed.
• This means that there is no expensive
waste of materials, as the unmixed
product remains usable indefinitely.
•They also eliminate the need for part
load charges and problems with over or
under-ordering.
•Our volumetric trucks can supply all
mixes and grades of cement, including
screed and mortar.

54. DRUM MIXERS
All the drum mixers have a container with a cross
section similar .
The blades are attached to the inside of the movable
drum.
Their main purpose is to lift the materials as the
drum rotates.
In each rotation, the lifted material drops back into
the mixer at the bottom of the drum and the cycle
starts again.
Parameters that can be controlled are the rotation
speed of the drum and, in certain mixers, the angle
of inclination of the rotation axis.
There are three main types of drum mixers:
• non-tilting drum;
• reversing drum;
• tilting drum.

55. •The reversing drum is similar to the non-tilting mixer except that the same opening
is used to add the constituents and to discharge concrete.
• The drum rotates in one direction for mixing and in the opposite direction for
discharging the concrete.
• There are two types of blades attached to the inner walls of the drum.
•One set drags the concrete upwards and toward the center of the mixer when the
drum rotates in one direction; the second set of blades pushes the concrete toward
the opening when the drum rotates in the other direction.
• The blades have a spiral arrangement to obtain the desired effect for discharge and
mixing.
•Reversing drum mixers are usually used for batches up to 1 m 3 m .

56. •The truck mixers belong to the reversing category of drum mixers.
• The driver of the truck can control the speed of rotation with a clutch in the cabin.
•Reversing drum mixer a type of concrete mixer that produces concrete in single batches.
•The entire drum rotates around its axis as materials are loaded through a charge chute at
one end of the drum and exit through a discharge chute at the opposite end of the drum.

57. PUMP
S•A pump is a device used to move liquids or slurries.
•A pump moves liquids from lower pressure to higher pressure, and overcomes this
difference in pressure by adding energy to the system.
•Pumps work by using mechanical forces to push the material, either by physically
lifting, or by the force of compression.
•Technically, a pump is a unit used for transportation of liquids, fluids and gases
through pipes or similar channels.
•The functionality of pumps is very simple, it consists of a suction mechanism at one
end where the material is drawn in. Counter pressure is developed at the other end
which forces the material out.
PUMP
S
piston pumps centrifugal pumpssubmersible pumps jet pumps

58. SUBMERSIBLE PUMP
•The whole assembly is submerged in the fluid to
be pumped.
•The advantage of this type of pump is that it can
provide a significant lifting force as it does not
rely on external air pressure to lift the fluid.
•The power source is usually an electric motor.
•Their compact and streamlined design makes
them ideal for wells and other jobs where space
is limited.
•These can be used for a depth of 80’ – 100’
depending on the depth of the water table.
Submersible pumps are found in many
applications, such as drainage, sewage pumping,
general industrial pumping and slurry pumping,
for water abstraction or in water wells.

59. •A concrete pump is a machine used for
transferring
•The first type of concrete pump is attached to
a truck.
• It is known as a trailer-mounted boom
concrete pump because it uses a remote-
controlled articulating robotic arm (called
a boom) to place concrete with pinpoint
accuracy.
• Boom pumps are used on most of the larger
construction projects as they are capable of
pumping at very high volumes and because of
the labor saving nature of the placing boom.
• They are a revolutionary alternative to truck-
mounted concrete pumps.

60. •The second main type of concrete pump is
either mounted on a truck and known as a
truck-mounted concrete pump or placed on
a trailer and it is commonly referred to as
a line pump or trailer-mounted concrete
pump.
• This pump requires steel or flexible concrete
placing hoses to be manually attached to the
outlet of the machine.
• Those hoses are linked together and lead to
wherever the concrete needs to be placed.
Line pumps normally pump concrete at lower
volumes than boom pumps and are used for
smaller volume concrete placing applications
such as swimming pools sidewalks and single
family home concrete slabs and most ground
slabs.

61. REQUIREMENTS FOR PUMPED CONCRETE:-
 Concrete mixture should neither be too harsh nor too sticky; also, neither too
dry nor too wet.
 A slump between 50 and 150 mm is recommended (note that pumping
induces partial compaction, so the slump at delivery point may be decreased)
 If the water content in the mixture is low, the coarse particles would exert
pressure on the pipe walls. Friction is minimized at the correct water
contents. The presence of a lubricating film of mortar at the walls of the pipe
also greatly reduces the friction.
 High cement content in concrete is generally beneficial for pumping.
 Water is the only pump able component in the concrete, and transmits the
pressure on to the other components.

62. • Two types of blockage to efficient pumping could occur: (1) Water can escape
from the mixture if the voids are not small enough; this implies that closely
packed fines would be needed in the mixture to avoid any segregation. The
pressure at which segregation occurs must be greater than that needed to pump
concrete. (2) When the fines content is too high, there could be too much
frictional resistance offered by the pipe. The first type of blockage occurs in
irregular or gap-graded normal strength mixtures, while the second type occurs
in high strength mixtures with fillers. In order to avoid these two types of failure,
the mixture should be proportioned appropriately.
• Other mixture factors that could affect pumping are the cement content, shape of
aggregate, presence of admixtures such as pumping aids or air entrainment. Air
entrainment is helpful in moderate amounts, but too much air can make pumping
very inefficient
• When flowing concrete is being pumped, an over-cohesive mixture with high
sand content is recommended. For lightweight aggregate concrete, pumping can
fill up the voids in the aggregate with water, making the mixture dry.