The document discusses various tests used to evaluate the properties of fresh and hardened concrete, including slump tests, compaction factor tests, Vee-Bee consistometer tests, flow tests, and Kelly ball tests for fresh concrete workability. Hardened concrete is evaluated using rebound hammer tests to estimate compressive strength and ultrasonic pulse velocity tests to assess quality. A case study describes a reinforced concrete structure collapse due to design flaws in accounting for beam-column joint forces, inadequate reinforcement detailing, and omitted column links.

1. WHAT IS CONCRETE ?
•Concrete is a composite
material composed of
water, coarse granular
material (the fine and
coarse aggregate or
filler) embedded in a hard
matrix of material (the
cement or binder) that
fills the space among the
aggregate particles
and glues them together.

2. MEASUREMENT OF WORKABILITY
 Workability depends upon –
 1.Water content
 2.Mix proportions
 3.Shape & Size of Aggregates
 4.Surface Texture of Aggregates
 5.Grading of Aggregates
 6.Use of Admixtures
 .Workability tests are commonly employed to measure
 -1.Slump Test
 2.Compacting Factor Test
 3.Flow Test
 4.Vee Bee ConsistometerTest
 5.Kelly Ball Test

3. TEST OF
CONCRETE

4. CONCRETE SLUMP TEST
Theory and Scope:-
The concrete slump test is an empirical test that
measures the workability of fresh concrete.
More specifically, it measures the consistency of
the concrete in that specific batch. This test is
performed to check the consistency of freshly
made concrete. Consistency is a term very closely
related to workability. It is a term which describes
the state of fresh concrete. It refers to the ease
with which the concrete flows. It is used to indicate
the degree of wetness. Workability of concrete is
mainly affected by consistency i.e. wetter mixes
will be more workable than drier mixes, but
concrete of the same consistency may vary in
workability. It is also used to determine consistency
between individual batches.
The test is popular due to the simplicity of
apparatus used and simple procedure.
Unfortunately, the simplicity of the test often
allows a wide variability in the manner that the
test is performed. The slump test is used to ensure
uniformity for different batches of similar concrete
under field conditions, and to ascertain the effects
of plasticizers on their introduction. In India this

5. PRINCIPLE OF SLUMP TEST
The slump test result is a slump of
the behaviour of a compacted
inverted cone of concrete under the
action of gravity. It measures the
consistency or the wetness of
concrete.
Apparatus
Metal mould, in the shape of the
frustum of a cone, open at both
ends, and provided with the handle,
top internal diameter 4 in (102 mm),
and bottom internal diameter 8 in
(203 mm) with a height of 1 ft
(305mm). A 2 ft (610 mm) long bullet
nosed metal rod, 5/8 in (16 mm) in
diameter.

6. INTERPRETATION OF RESULTS
The slumped concrete takes various shapes, and according to the profile of slumped concrete, the
slump is termed as true slump, shear slump or collapse slump. If a shear or collapse slump is
achieved, a fresh sample should be taken and the test repeated. A collapse slump is an indication
of too wet a mix. Only a true slump is of any use in the test. A collapse slump will generally mean
that the mix is too wet or that it is a high workability mix, for which slump test is not appropriate.
Very dry mixes; having slump 0 – 25 mm are used in road making, low workability mixes; having
Collapse Shear True
In a collapse
slump the
concrete
collapses
completely.
In a shear
slump the top
portion of the
concrete
shears off and
slips sideways.
In a true slump
the concrete
simply
subsides,
keeping more
or less to
shape.
slump 10 – 40 mm are used for foundations with light reinforcement,

7. Compaction Factor Test

Aim: To find out the compaction factor for the given
fresh mix of concrete.
 Theory:Work-ability of concrete is the ability/ease
with which concrete can be mixed, transported and
placed. This is a major factor which contributes to
the other properties of concrete also. If concrete is
workable enough then it can be compacted with
less compacting effort. So there is a relation
between the amount of work required to compact a
given fresh concrete and the work-ability of the
concrete. This relation is well suited for the concrete
of the low water cement ratio. Slump cone test is
also used to find out the work-ability of the
concrete but only recommended for the concrete of
higher work-ability. For less workable
concrete(having less water cement ratio),
compaction is standardized by various standards.
 Apparatus: Compaction factor apparatus/machine,
weighing balance, cow/mixing tray.

8. CALCULATIONS
Let weight of the empty cylinder = W1
Let weight of the cylinder with the partially compacted concrete =
W2
Let weight of the fully compacted(Using mechanical vibrator)
concrete with cylinder = W3
Compaction Factor = Weight of the partially compacted concrete/
Weight of the fully compacted concrete
i.e., Compaction factor = (W2-W1)/(W3-W1)
Result: The compaction factor of the given fresh concrete mix is .....
(concretNote: Relation between the compaction factor and work-ability
is that higher the compaction factor higher is the work-ability.
Theoretical maximum value of the compaction factor can be 0.96 to
1.0 packted .

9. VEE BEE CONSISTOMETER TEST
 Vee Bee ConsistometerTest:Vee Bee Consistometer
test is done on concrete that is either too dry for
slump test or compaction test. It is done to
determine the consistency of low slump concrete.
 Specifications : The equipment consists of : A
Vibrating Table size 380mm long and 260mm wide,
resting upon elastic support at a height of about
305mm above the floor, complete with start/stop
switch, cord and plug. A holder is fixed to the base
into which a swivel arm is telescoped with funnel
and guide sleeve. The swivel arm is also detachable
from the Vibrating Table. A graduated rod is fixed on
a swivel arm and at its end a plastic disc is screwed.
The division of scale on the rod record the slump of
the concrete in millimeters, supplied complete with
a sheet metal container with lifting handles which
can easily be fixed to the Vibrating Table. A slump
cone open at both ends with lifting handles and a
Tamping rod of size 16mm dia and 600mm long,
rounded at one end.

10. USING A VEE-BEE CONSISTOMETER
To use a Vee-Bee Consistometer, a conventional slump test is performed. For conducting the
test, a slump cone is placed in the inside part of a Vee-Bee Consistometer.
When the mixture is poured, a Glass Disc attached to the swivel arm turns and is placed on
top of the concrete in the machine. This triggers an electric vibrator and initiates the stop-watch
as well.
Vibration continues till the conical shape of the concrete disappears and the concrete takes a
cylindrical shape.
When the mixture assumes a complete cylindrical shape, the stop watch switches off
immediately.
This time is recorded to understand the consistency of the mixture, which is generally
expressed in VB Degrees, which is equal to the time recorded in seconds.

11. FLOW TEST
 The flow table test or flow test is a method to
determine the consistence of fresh concrete.
 Application When fresh concrete is delivered to a site
by a truck mixer it is sometimes necessary to check its
consistence before pouring it into formwork.
 If the consistence is not correct, the concrete will not
have the desired qualities once it has set, particularly
the desired strength. If the concrete is too pasty, it
may result in cavities within the concrete which leads
to corrosion of the rebar, eventually leading to the
formation of cracks (as the rebar expands as it
corrodes) which will accelerate the whole process,
rather like insufficient concrete cover. Cavities will
also lower the stress the concrete is able to support.
Equipment
Flow table with a grip and a hinge, 70 centimetres (28 in) square.
Abrams cone, open at the top and at the bottom - 30 centimetres (12 in) high, 17 centimetres
(6.7 in) top diameter, 25 centimetres (9.8 in) base diameter.
Water bucket and broom for wetting the flow table.
Tamping rod, 60 centimetres (24 in) long

12. CALCULATION
The flow of the concrete is the percentage increase in
diameter of spread concrete over the base diameter of
the moulded concrete, calculated from the following
formula.
REPORT
The flow measured is to be reported in terms of
percentage.
SAFETY & PRECAUTIONS
Use hand gloves, shoes at the time of test.
Keep the mould & flow table clean, dry & free from
sticking concrete.
Keep the vertical shaft lubricated with light oil.
Keep the contact faces of the flow table top &
supporting frame oiled.
Keep the hand wheel, the adjustable shaft &
universal joint.

13. KELLY BALL TEST
 General description

 This method is used to determine
the penetration of a
hemispherical metal weight into
freshly mixed concrete, which is
related to the workability of the
concrete.
The apparatus consists of a
cylinder with one end having a
hemispherical shape and the
other end fit with a graduated
handle. The weight assembly is
lowered through a frame into the
concrete and the penetration
measured. Weight approx.: 15 kg

14. REBOUND HAMMER
Rebound hammer test is done to find out the compressive strength of
concrete by using rebound hammer as per IS: 13311 (Part 2) – 1992. The
underlying principle of the rebound hammer test is
The rebound of an elastic mass depends on the hardness of the surface
against which its mass strikes. When the plunger of the rebound hammer
is pressed against the surface of the concrete, the pring-controlled mass
rebounds and the extent of such a rebound depends upon the surface
hardness of the concrete. The surface hardness and therefore the rebound
is taken to be related to the compressive strength of the concrete. The
rebound value is read from a graduated scale and is designated as the
rebound number or rebound index. The compressive strength can be read
directly from the graph provided on the body of the hammer.

15. PROCEDURE TO DETERMINE STRENGTH OF
HARDENED CONCRETE BY REBOUND HAMMER
i) Before commencement of a test, the rebound
hammer should be tested against the test
anvil, to get reliable results, for which the
manufacturer of the rebound hammer indicates
the range of readings on the anvil suitable for
different types of rebound hammer.
ii) Apply light pressure on the plunger – it will
release it from the locked position and allow it
to extend to the ready position for the test.
iii) Press the plunger against the surface of the
concrete, keeping the instrument
perpendicular to the test surface. Apply a
gradual increase in pressure until the hammer
impacts. (Do not touch the button while
depressing the plunger. Press the button after
impact, in case it is not convenient to note the
rebound reading in that position.)
iv) Take the average of about 15 readings.

16. INTERPRETATION OF RESULT
The rebound reading on the indicator
scale has been calibrated by the
manufacturer of the rebound hammer for
horizontal impact, that is, on a vertical
surface, to indicate the compressive
strength. When used in any other
position, appropriate correction as given
by the manufacturer is to be taken into
account.

17. ULTRASONIC PULSE VELOCITY
This test is done to assess the quality of
concrete by ultrasonic pulse velocity
method as per IS: 13311 (Part 1) – 1992.
The underlying principle of this test is -
The method consists of measuring the
time of travel of an ultrasonic pulse
passing through the concrete being
tested. Comparatively higher velocity is
obtained when concrete quality is good
in terms of density, uniformity,
homogeneity etc

18. PROCEDURE TO DETERMINE STRENGTH OF HARDENED
CONCRETE BY ULTRASONIC PULSE VELOCITY.
i) Preparing for use: Before switching on the ‘V’ meter, the transducers should be connected to
the sockets marked “TRAN” and ” REC”.
The ‘V’ meter may be operated with either:
a) the internal battery,
b) an external battery or
c) the A.C line.
ii) Set reference: A reference bar is provided to check the instrument zero. The pulse time for
the bar is engraved on it. Apply a smear of grease to the transducer faces before placing it on
the opposite ends of the bar. Adjust the ‘SET REF’ control until the reference bar transit time is
obtained on the instrument read-out.
iii) Range selection: For maximum accuracy, it is recommended that the 0.1 microsecond range
be selected for path length upto 400mm.
iv) Pulse velocity: Having determined the most suitable test points on the material to be tested,
make careful measurement of the path length ‘L’. Apply couplant to the surfaces of the
transducers and press it hard onto the surface of the material. Do not move the transducers
while a reading is being taken, as this can generate noise signals and errors in measurements.
Continue holding the transducers onto the surface of the material until a consistent reading
appears on the display, which is the time in microsecond for the ultrasonic pulse to travel the
distance ‘L’. The mean value of the display readings should be taken when the units digit hunts
between two values
.

19. Pulse velocity=(Path length/Travel time)
v) Separation of transducer leads: It is advisable to prevent the
two transducer leads from coming into close contact with each
other when the transit time measurements are being taken. If
this is not done, the receiver lead might pick-up unwanted
signals from the transmitter lead and this would result in an
incorrect display of the transit time.

20. INTERPRETATION OF RESULTS
The quality of concrete in terms of
uniformity, incidence or absence of
internal flaws, cracks and segregation,
etc,indicative of the level of workmanship
employed, can thus be assessed using the
guidelines given below, which have been
evolved for characterizing the quality of
concrete in structures in terms of the
ultrasonic pulse velocity.

22. CASE
STUDY

23. Collapse of a reinforced
concrete structure,
This factory building included
concrete columns and a
steel truss for the roof.

35. • Two people were killed
• Design error. No consideration was given in the
calculations of how forces were transmitted
through the
joint between the edge beam and column.
• Detailing error. Inadequate connection between
beam
and column reinforcement.
• Construction error. Column links were excluded for
convenience
SUMMARY

36. Civil A2
Santu Dey
Surajit Mondal
Satyajit Roy
Supriyo Sarkar
Santunu Mondal
Sumangal Kundu

37. THE
END