global academy of technologyphysical balance, specific gravity bottle of 50ml capacity, clean...

GLOBAL ACADEMY OF TECHNOLOGY

Ideal Homes Township,

Rajarajeshwari Nagar, Bangalore – 560098

LABORATORY RECORD

NAME :

U. S. N. :

SUBJECT :

SUBJECT CODE :

CLASS :

STRUCTURAL ENGINEERING LAB - 1

GLOBAL ACADEMY OF TECHNOLOGY (2018-19) Page 1

TABLE OF CONTENTS

1. Specific Gravity of cement (IS 269-1989 and IS 4031-1988) 02

2. Mix Design of Concrete (IS 10262-2009) 04

3. Split Tensile Strength of Concrete 08

4. Compressive Strength of Concrete 12

5. Flexural Strength of Concrete 15

6. Assessment of Strength and Quality of Concrete 18

a. Rebound Hammer 18

b. Ultrasonic Pulse Velocity (UPV) meter 21

7. Assessment of dynamic parameters of given model using Shake Table 24



EXPERIMENT NUMBER: 01

SPECIFIC GRAVITY OF CEMENT IS: 269-1989 AND IS: 4031-198 8)

AIM:

To determine the specific gravity of given sample of hydraulic cement.

APPARATUS:

Physical balance, specific gravity bottle of 50ml capacity, clean Kerosene.

THEORY:

Specific gravity is defined as the ratio between weights of a given volume of material

and weight of an equal volume of water. To determine the specific gravity of cement,

kerosene is used which does not react with cement.

Fig. 1 Specific gravity bottle

CODAL REFERENCE:

IS: 269 -1989 AND IS: 4031-1988



PROCEDURE:

Clean and dry the specific gravity bottle and weigh it with the stopper (W1).

Fill the specific gravity bottle with cement sample at least half of the bottle and weigh

with stopper (W2).

Fill the specific gravity bottle containing the cement, with kerosene (free of water)

placing the stopper and weigh it (W3).

While doing the above do not allow any air bubbles to remain in the specific gravity

bottle.

After weighing the bottle, the bottle shall be cleaned and dried again.

Then fill it with fresh kerosene and weigh it with stopper (W4).

All the above weighing should be done at the room temperature of 27°c + 10°c.

OBSERVATIONS:

Weight of empty specific gravity bottle: W1 = gms.

Weight of the bottle with cement: W2 = gms.

Weight of the bottle with cement and kerosene: W3 = gms.

Weight of bottle with fresh kerosene: W4 = gms.

Specific gravity of kerosene =

FORMULA:

Specific Gravity of Cement = (W2−W1)

(W2−W1)−(W3−W4)x0.79

CALCULATION:

Specific Gravity of Cement =

RESULT:

The specific gravity of cement is




DESIGN THE MIX AS PER IS 10262-2009 FOR THE MATERIAL

PROCEDURE CHARACTERIZED

AIM:

To obtain mix proportion for M25 grade concrete.

STIPULATION FOR PROPORTIONS:

1. Grade Designation M25

2. Type of cement OPC 53 grade

3. Maximum Nominal Aggregate Size 20mm

4. Minimum water cement ratio 0.5

5. Minimum Cement Content 300kg/m3

6. Maximum Cement Content 450kg/m3

7. Workability 100mm (slump)

8. Method of Concrete Placing Manual

9. Exposure Condition Moderate

10. Degree of Supervision Good

11. Type of Aggregate Angular aggregate

12. Chemical Admixture Type

TEST DATA FOR MATERIALS:

1. Cement Used Birla Super 53 grade

2. Specific Gravity of Cement 3.15

3. Specific Gravity of Water 1.00

4. Specific Gravity of Coarse Aggregate 2.68

5. Specific Gravity of Fine Aggregate 2.56



6. Water Absorption Coarse Aggregate Nil

7. Water Absorption of Fine Aggregate Nil

8. Free Moisture Content of Coarse

Aggregate

Nil

9. Free Moisture Content of Fine Aggregate Nil

10. Fine Aggregate Conforming to Zone-II

Mix proportions for M25 concrete:

Cement = --------

Water = --------

Fine aggregate =--------

Coarse aggregate =---------

Chemical admixture = --------

Water cement ratio = ----------




SPLIT TENSILE STRENGTH OF CONCRETE

AIM: To determine the split tensile strength of concrete.

APPARATUS: Weights and weighing device, tools, containers for mixing, testing

machine, cylinder, tamping rod.

THEORY:

The tensile strength is one of the basic and important properties of the concrete. The

concrete is not usually expected to resist the direct tension because of its low tensile

strength and brittle nature. However, the determination of tensile strength of concrete

is necessary to determine the load at which the concrete members may crack. The

cracking is a form of tension failure.

Apart from the flexure test the other methods to determine the tensile strength of

concrete can be broadly classified as (a) direct methods, and (b) indirect methods. The

direct method suffers from a number of difficulties related to holding the specimen

properly in the testing machine without introducing stress concentration, and to the

application of uniaxial tensile load which is free from eccentricity to the specimen. As

the concrete is weak in tension even a small eccentricity of load will induce combined

bending and axial force condition and the concrete fails at the apparent tensile stress

other than the tensile strength.

As there are many difficulties associated with the direct tension test, a number of

indirect methods have been developed to determine the tensile strength. In these tests

in general a compressive force is applied to a concrete specimen in such a way that the

specimen fails due to tensile stresses developed in the specimen. The tensile stress at

which the failure occurs is termed the tensile strength of concrete.



The splitting tests are well known indirect tests used for determining the tensile strength

of concrete sometimes referred to as split tensile strength of concrete. The test consists

of applying a compressive line load along the opposite generators o f a concrete cylinder

placed with its axis horizontal between the compressive platens. Due to the compression

loading a fairly uniform tensile stress is developed over nearly 2/3 of the loaded

diameter as obtained from an elastic analysis.

Fig. 4 Split tensile strength of concrete

CODAL REFERENCE:

IS 5816 – 1999 (Method of Test Splitting Tensile Strength of Concrete)

PROCEDURE:

Prepare a concrete mix as mentioned in IS 10262:2 009 to design the proportion of

designed mix by mechanical mixer.

Prepare three testing cylinder, make sure that they are clean and greased or oiled thinly.

Fill the cylinder in 3 layers, tamping each layer with 25 blows using tamping rod.

Fill moulds completely, smooth off the top evenly and clean up any concrete outside

the cylinders.



Leave the specimen to set in mould for 24hrs.

After 24hrs open the mould and immerse in water for 28 days for curing.

Before testing ensure that all testing machine, bearing surface is cleaned thoroughly.

Carefully place the cylinder at the centre and lower the plates and ensure that the plates

are in contact with the top surface of the cylinder.

Apply a constant load of 3.5KN/s until the failure is approached, and record the

maximum load applied on the cylinder.

Using the formula, (2P/πdl), tensile strength is calculated.

FORMULA:

fcn=2P

πdl

fcn= Split tensile strength of concrete

P = load

d = diameter

l = length

OBSERVATION AND CALCULATION:

RESULT:

The Split tensile Strength of the given concrete is N/mm2

FAILURE PATTERN:

Sl. No. Load (KN)

(P)

Split tensile strength of concrete in MPA

(28days)

1

2

3




COMPRESSIVE STRENGTH OF CONCRETE

AIM:

To determine the compressive strength of concrete.

APPARATUS:

Universal Testing Machine (UTM), Cubes, Weighing machine, tools.

THEORY:

The test method covers determination of compressive strength of cubic concrete

specimens. It consists of applying a compressive axial load to cubes at a rate which is

within a prescribed range until failure occurs. The compressive strength is calculated

by dividing the max lo ad attained during the test by the cross sectional area of the

specimen.

Fig. 4 Compressive test of concrete

CODAL REFERENCE:

IS 516-1959 (Method of tests for strength of concrete)



PROCEDURE:

Prepare a concrete mix as mentioned in IS 10262:2009 to design the Proportion of

designed mix concrete ingredients by mechanical mixer.

Prepare three testing cubes and make sure that they are clean and greased by oil thinly.

Metal moulds should be sealed to their base plates to prevent loss of water.

Fill the cubes in 3 layers, tamping each later with 25 strokes using a tamping rod.

Fill the moulds completely, smooth off the top layer evenly, and clear up any concrete

outside the cubes.

Leave the specimen in the curing tank for 24hrs.

After that open the mould and immerse in water for 28 days for curing.

Before testing ensure that all testing machine, bearing surface is cleaned thoroughly.

Carefully place the cube at the centre and lower the plates and ensure that the plates are

in contact with the top surface of the cube.

Apply a constant load of 3.5KN/s until the failure is approached, and record the

maximum load applied on the cube.

FORMULA:

Compressive strength, (fck) = Load

Area


Sl. No. Load(KN) Compressive strength of concrete (28days) in

MPa

1

2

3

RESULT:

The Compressive Strength of the given concrete is N/mm2




FLEXURAL STRENGTH OF CONRETE

AIM:

To determine flexural strength of the concrete.

APPARATUS:

Flexural strength testing machine, weights and weighing balance, tools and container

for mixing and tamping rods.

THEORY:

Flexural strength is one measure of the tensile strength of concrete. It is a measure of

an unreinforced concrete beam or slab to resist failure in bending. Flexural strength is

one measure of the tensile strength of concrete. It is a measure of an unreinforced

concrete beam or slab to resist failure in bending.

Fig. 5 Flexural strength of concrete

CODAL REFERENCE:

IS 516:1959



PROCEDURE:

Prepare a concrete mix as mentioned in IS 10262:2009 to design the proportion of

designed mix concrete ingredient to mechanical mixer.

Prepare three flexural beams and make sure that they are clean and greased and oiled

thinly.

Metal moulds should be sealed to their base plate to prevent loss of water.

Fill the beam in 3 layers, tamping each layer with 25 blows using tamping rod.

Fill the mould completely, smooth off the top evenly and clean up any concrete outside

the beam.

Leave the specimen in curing period for 28 days after it is detached from mould after

24hrs.

Ensure that it is surface dried with cloth and load is applied on the beam with help of

loading frame at centre.

Apply at a constant load of 3.5KN/s until the failure is achieved. Record the max load

applied to each beam.

FORMULA:

Modulus of rupture, fb = PLeff

bd2


Sl. No. Load (KN) Split tensile strength of concrete (28days) in

(N/mm2 )

1

2

3

FAILURE PATTERN:



RESULT:

The Flexural Strength of the given concrete is N/mm2




ASSESSMENT OF STRENGTH AND QUALITY OF CONCRETE

NON-DESTRUCTIVE TESTING APPARATUS (NDT)

1. REBOUND HAMMER:

AIM:

Rebound hammer test is done to find out the compressive strength of concrete and

quality of concrete by using rebound hammer as per IS: 13311 (Part 2) – 1992.

PRINCIPLE:

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 spring-controlled mass rebounds and the extent of such a rebound

depends upon the surface hardness of the concrete.

APPARATUS:

Rebound Hammer, Test specimen.

THEORY:

Rebound hammer test is quick method for assessing the quality of concrete based on

surf ace hardness indicated by the rebound hammer. Higher the rebound value indicates

higher strength surface hardness of concrete. Most commonly used equipment is Submit

rebound hammer. This equipment works on the principle that the spring controlled mass

slides on a plunger within a tubular housing.

Fig. 6 Rebound Hammer



CODAL REFERENCE:

IS 13311 – 1992 part 2

PROCEDURE:

Preparation of test surface: For heavily textured, soft or surface with loose shell be

ground smooth with the abrasive stone. For old concrete surface grinding is not feasible

without power equipment.

Firmly hold the instrument in a position that allows the plunger to strike the surface

tested.

After the impact, note down the reading obtained from the instrument. Repeat the trial

continuously for 8 – 10 trails and note down the reading obtained by each trail.

Take mean of all the trials and from the standard graph, the strength of concrete can be

determined corresponding to the value obtained during the experiment.

Depending upon the position of plunger, the corresponding curve should be chosen, to

determine strength.

i.e., Horizontal = 0° curve.

Vertical upwards = 90° curve.

Inclined = 45° curve.

Vertically downward = - 90° curve.




RESULT:

The Compressive Strength of the given specimen is N/mm2




ASSESSMENT OF STRENGTH AND QUALITY OF CONCRETE

2. ULTRASONIC PULSE VELOCITY (UPV) METER

AIM:

To find out strength and quality of the given concrete specimen using UPV meter.

PRINCIPLE:

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.

APPARATUS:

Portable ultrasonic non-destructive digital interface (PUNDIT)

Two transducer leads

Reference bar (or) Standard bar (or) Calibrating bar

Tin of couplant

THEORY:

This method of test is being extensively used to assess the quality and strength of in-

situ concrete in structural member. This test is generally used to check the compaction

of concrete, uniformity of concrete, determination of cracks, presence of honey combs

and also strength estimation. Most popular experiment used for UPV test is PUNDIT

and TICO meter.

This method covers the determination of pulse velocity of propagation of compression

wave in concrete. The pulse velocity ‘v’ is related to the principle properties of a solid

by the equation.

V2 = KE/D (Code referred- IS 13311 – 1992 part 1)



where,

K = Constant.

D = Density.

E= Elastic Modulus

Fi g. 3 Ultra-sonic Pulse Velocity Meter

CODAL REFERENCE:

IS 13311 – 1992 part 1.

PROCEDURE:

There are basically 3 methods to carry out the test procedure:

1. Direct transmission

2. Semi-direct transmission

3. Indirect transmission

Before switching PUNDIT, transducer should be connected to the sockets marked. The

PUNDIT may be operated from either

1. Internal batter y

2. External battery (suitable for field)

3. AC main supply

For the AC main supply, plug the main cable into the 3 w ay socket and switch on the

main. By using the rest button switch on PUNDIT.



Before using PUNDIT, it should be calibrated by using reference bar. After putting the

coupling agent as the transducer faces, the transducer faces are

Placed and pressed against the reference bar ends. Using the set free button the reading

of the instrument should be adjusted to read the transit time recorded on the calibration

bar.

After applying an appropriate coupling agent to the transducer diaphragms press the

faces of the transducer against the surface of the concrete and measure the transit time.

Measure the length of the shortest direct path between the centres of the diaphragms

velocity is calculated using the formula:

Pulse velocity (V) = Path length(L)

Travel time(T)

Obtained value i.e., velocity is compared with the standard grading chart.

Pulse velocity (km/sec) Concrete Quality (Grading)

Above 4.5 Excellent

3.5 to 4.5 Good

3.0 to 3.5 Medium

Below 3 Doubtful


Sl. No. Length

(mm)

(L)

Time (sec)

(T)

Pulse velocity

(km/sec)

Quality of

concrete

1

RESULT:

The grading/quality of concrete is




ASSESSMENT OF DYNAMIC PARAMETERS OF GIVEN MODEL

USING SHAKE TABLE

AIM:

To find out the displacement, velocity and acceleration of the given model using shake

table.

PRINCIPLE:

The method consists of measuring the dynamic parameters of the scale model of the

structure by including the vibrations into the model using shake table

APPARATUS:

Shake table with digital controller

Accelerometers

Data acquisition system connected to computer

Scaled model

THEORY: This is most commonly used to ascertain the behaviour of the structure

under dynamic lading. Vibrations are induced to the model using either specific set of

waves or earlier earthquake data by means of serve controlled platform via computer.



PROCEDURE:

Shake table to be connected to computer via a digital to analogue controller.

Scaled model of the structure shall be firmly fixed the base of the shake table by means

of bolts

Accelerometers to be mounted at levels under observation and connected to the data

acquisition system by connecting leads

Data acquisition system then will be connected to the computer via. USB port.

Power on the DAS, DAC and computer

The shake table is controlled by shake software and the data obtained using DAS will

be displayed through KAMPANA software

Open shake software and initialize the table by moving it to one extreme end of

operation

Set the recording time as (Period of earthquake data selected + Time required to start

vibration + Free vibration time) and start the recording

Immediately shift to the shake software and press start to begin the experiment

After the recording time, completed the data acquired can be saved to spread sheet

format

Displacement, Velocity and acceleration obtained at different levels can be noted from

the spread sheet saved



OBSERVATION:

Sl. No. Channels Displacement

For Frequency

2.8 Hz &

Amplitude=1

Displacement For

Frequency

7.9Hz &

Amplitude=1

Displacement For

Frequency

11.37Hz &

Amplitude=1

1 Channel 1

2 Channel 2

3 Channel 3

4 Channel 4

MODE SHAPES:

global academy of technologyphysical balance, specific gravity bottle of 50ml capacity, clean...

Documents