gives you some brief explanation

1. UNIT-V
 A presentation ON
 CONCRETEING EQUIPMENT & AGGREGATE
PROUDCUTION EQUIMENT
 By
B.MAHESHBABU

2. CONCRETING EQUIPMENT
 Before going to learn about concrete equipment we
have to study the concrete manufacturing steps
 All the equipment prominently used in
manufacturing process of concrete
 Concrete is mixture of cement ,fine aggregate ,and
coarse aggregates are in proper portions
 A method for producing Portland cement was
patented by Joseph Aspdin in 1824.
 Reinforced concrete was invented in 1849
by Joseph Monier.

3. CONCRETE GRADES
 M-5- 1:5:10
M-7.5 -1:4:8
M-10 - 1:3:6
M-15 - 1:2:4
M-20 - 1:1.5:3
M-25 -1:1:2
M-30 - M-40 - Design Mix Followed

4.  The 'M' denotes 'Mix' followed by a number
representing the compressive strength of
that mix in N/mm^2.
A mix is a specific ratio in which cement, fine(sand)
and coarse aggregate(gravel) are mixed.

5. CONCRETE PRODUCTION STEPS
 The various stages of manufacture of concrete are:
(a ) Batching
(b) Mixing
(c ) Transporting
(d placing
(e) Compacting
(f ) Curing
(g) Finishing.

6. BATCHING
 Batching is the process of measuring concrete mix
ingredients by either mass or volume and
introducing them into the mixer .
 To produce concrete of uniform quality,
 The ingredients must be measured accurately for
each batch

7. VOLUME BATCHING

8.  Volume Batching: Volume batching is not a good
method for proportioning the material because of
the difficulty it offers to measure granular material in
terms of volume.
 for any small job, concrete may be batched by
volume

9.  This method is generally adopted for small jobs
 Gauge boxes are used for measuring the fine and
coarse aggregate. •
 The volume of gauge box is equal to the volume of
one bag of cement.
 Gauge box are also called as FARMAS
 They can be made of timbers or steel. They are
made generally deep and narrow
 While filling the gauge boxes the material should
be filled loosely, no compaction is allowed.

10.  Weigh Batching: Weigh batching is the correct
method of measuring the materials.
 Use of weight system in batching, facilitates
accuracy, flexibility and simplicity.
 Large weigh batching plants have automatic
weighing equipment.
 On large work sites, the weigh bucket type of
weighing equipment's are used.

11.  Batching by weight is more preferable to volume
batching ,as it is more accurate and leads to more
uniform proportioning.
 It does not have uncertainties associated with
bulking. It’s equipment falls into 2 general
categories :
 I. Semi automatic, II. Fully automatic.

12.  In case of semi automatic batching the aggregate
bin gates are opened by manually operated
switches . And gates are closed automatically when
the material has been delivered. This system also
contains interlock which prevents charging and
discharging

13. FULLY AUTOMATIC

14.  In case of automatic batching the material are
electrically activates by a single switch and
complete autographic record are made of the
weight of each material.
 The batching plant comprises 2,3,4 or 6
compartment bins of several capacities.
 Over the conveyer belt the weigh batchers
discharging are provided below the bins

15. MIXING
 The mixing should be ensure that the mass
becomes Homogeneous , uniform in colour and
consistency .
 Methods of Mixing :
 1.Hands(using hand shovels)
 2.Stationary Mixers
 3.Ready mix concrete

16. HAND MIXING

17. HAND MIXING
 Mixing ingredients of concrete by hands using
ordinary tools like, hand shovels etc.
 This type of mixing is done for Less output of
concrete.

18. CONCRETE MIXERS (STATIONARY)
 Concrete mixers are two types
 Free fall mixers
 Power mixers
Again free fall are two types and power mixers
also
Concrete is sometime mixed at jobsite in a
stationary mixer having a size of 9 cubic meter

19. FREE FALL MIXERS
 Free fall mixing is suitable for the concrete with 2-inch minimum slump
and are not too hard
 This type of mixers are used at site of construction
 The drum of freefall mixer can be filled and emptied by changing the
direction of rotation
 There are two major type namely
 TILTING MIXER
 REVERSIBLE MIXER

20. TILTING MIXER

22. TILTING MIXER
 A concrete mixer is a device that homogeneously
combines cement, aggregate such as sand or
gravel, and water to form concrete
 It was invented by Gebhardt Jaeger
 A typical concrete mixer uses a revolving drum to
mix the components.

23.  For smaller volume works portable concrete mixers
are often used so that the concrete can be made at
the construction site, giving the workers ample time
to use the concrete before it hardens
 An alternative to a machine is mixing concrete by
hand. This is usually done in a wheelbarrow;
however, several companies have recently begun
to sell modified tarps for this purpose.
 Major parts are wheel and axes ,Drum(9 cu.m
approx) ,engine, tilting hooper
 Engine maybe powered by electric, diesel

24.  Usually, the material is loaded manually into the
drum from ground level and the Hooper dumps the
material tilting up mechanically

25. REVERSIBLE MIXERS

27.  In reversible mixer, The drum has one horizontal
axis, around which the drum rotates
 There are two openings to the drum, one for
loading the material and other for discharging
 Usually self loading
 Self operation
 Large size unit compared to traditional mixer
 Major parts, wheel barrow, tilting hopper, self and
loaders ( bucket)
 Electric operated and diesel operated

28. POWER MIXERS
 Pan mixer

31. POWER MIXERS
 Pan mixer is a type of mixer which has a fixed pan
or removable tub with a vertical mixer unit in it as
opposed to a typical cement mixer which has a
horizontal rotating barrel with fixed beaters.
 A mixer filled through an opening at its top; for con
crete, usually a pan or drum within
which mixing blades revolve about the vertical axis;
for mortar, usually a trough within which mixing pad
dles revolve about the horizontal axis.

32.  Some concrete batching plants use a large pan
mixer to pre mix the concrete before it is loaded
into mixer trucks(Transit mixer in USA) to be
delivered to site.
 British company Liner introduced the first Pan
Mixer design in 1924
 major parts are rotating drum and paddles and
cap
 These electrically operated

33. FACTORS EFFECTING THE OUTPUT OF MIXERS
 Rotating speed of mixer
 Capacity of mixer
 Including mixing time
 loading and unloading time
 Operation time

34. READY MIXED CONCRETE
 Ready mixed concrete is proportioned and mixed
off at the project site and is delivered to the
construction area in a freshly mixed and
unhardened state. It can be manufactured by any of
the following methods:
 1.Central-mixed concrete
 2.Truck-mixed concrete

35. CENTRAL MIXED CONCRETE
 Central-mixed concrete : mixed completely in a
stationary mixer
 delivered in
 Agitator Trucks
 A non-agitating truck

37. AGITATOR TRUCKS
 A vehicle carrying a drum or agitator body, in which
freshly mixed concrete can be conveyed from the
point of mixing to that of placing, the drum being
rotated continuously to agitate the contents.
 Advantages: Operate usually from central mixing
plants
 Watch for: Timing of deliveries should suit job
organization. Concrete crew and equipment must
be ready onsite to handle concrete.
 Used for: Transporting concrete for all uses. Haul
distances must allow discharge of concrete within
1½ hours.

38. NON AGITATING TRUCK

39. NON-AGITATING TRUCKS
 Used for: Transport concrete on short hauls(small
distance) over smooth roadways.
 Advantages: Cost of non-agitating equipment is
lower than that of truck agitators or mixers.
 Watch for: Slump should be limited.
 Possibility of segregation

40. TRUCK MIXED

42. TRUCK-MIXED CONCRETE
 Used for: Intermittent (periodic) production of
concrete at jobsite, or small quantities.
 Advantages:
 Combined materials transporter and batching and
mixing system.
 One-man operation

43.  1) Mortar Pan : Concrete is carried in small Quantities
 2) Wheelbarrows and Buggies : Short flat hauls on all
types of onsite concrete construction
 3) Belt Conveyors : Conveying concrete horizontally or
higher/lower level.
 4) Cranes and Buckets : Used forWork above ground
level , Buckets use with Cranes, cableways,
 5) Pumps : Conveying concrete from central discharge
point to formwork.
 6) Transit Mixer : used for transporting the concrete
over long distance particularly in RMC plant .

44. MORTAR PAN

45. WHEEL BORROW

46. CONVEOYRS

47. CABLES AND CRANES

48. TRANSIT MIXER

49. COMPACTION OF CONCRETE
 Compaction of concrete is process adopted for
expelling the entrapped air from the concrete
 In the process of mixing , transporting and placing
of concrete air is likely to get entrapped in the
concrete .
 It has been found from the experimental studies
that 1% air in the concrete approximately reduces
the strength by 6%.
 If we don’t expel this air, it will result into
honeycombing and reduced strength

50.  Different Methods Of Concrete Compaction
 1) Hand Compaction Roding, Ramming ,Tamping 2)
Compaction by Vibration

51. HAND COMPACTION
 Hand compaction is used for ordinary and unimportant
structures. Workability should be decided in such a way
that the chances of honeycombing should be minimum.
The various methods of hand compaction are as given
below
 Roding It is a method of poking with 2m long, 16 mm
dia. rod at sharp corners and edges. The thickness of
layers for rodding should be 15 to 20 cm.
 Ramming • It is generally used for compaction on
ground in plain concrete. It is not used either in RCC or
on upper floors.
 Tamping • It is a method in which the top surface is
beaten by wooden cross beam of cross section 10 cm x
10 cm. both compaction and leveling are achieved
simultaneously. It is mainly used for roof slabs and road
pavements.

52. RODING

53. RAMMING

54. TAMPING

55. VIBRATION
 Vibration is imparted to the concrete by mechanical
means. It causes temporary liquefaction so that air
bubbles come on to the top and expelled ultimately.
Mechanical vibration can be of various types as
given under.
 Internal Vibration It is most commonly used
technique of concrete vibration.
 We follow different methods in vibration
 External Vibration
 Table Vibration

56. CURING
 Curing is the process in which the concrete is
protected from loss of moisture and kept within a
reasonable temperature range. The result of this
process is increased strength and decreased
permeability. Curing is also a key player in
mitigating cracks in the concrete, which severely
impacts durability.

57. CURING BY GUNNY BAGS

58.  THANK YOU