The document discusses testing the flexural strength of concrete. It provides details on the test setup and procedures. The flexural strength test is used to determine a material's ability to resist bending or deformation under a load. The test involves placing a concrete specimen on supporting rollers spaced at specific distances and applying a load through top rollers at the midpoint. The maximum load applied before failure is used to calculate the flexural strength based on the specimen's dimensions and load. Test equipment requirements and specifications are also outlined.

1. GURU KASHI UNIVERSITY
Effect on the Compressive Strength of the Concrete by
Addition of Polypropylene Fibre in M20 Grade of Concrete
Submitted By:
Gursharan Singh
Roll No. 171451009
Under the Guidance of
Jaspreet Singh

3. INTRODUCTION
•Concrete is world’s most widely used construction material. Due to its low
tensile strength and a low tensile strain limit it results in the development of
microcracks in it. So in order reduce this effects polypropylene fibers can be
used.
•Excessively wide cracks can also result in leakage in structures such as dams,
tanks, and pools. In many of the cases this cracking is so significant that it may
lead to failure of the structure. The deterioration of such structures is of great
concern since the repairing and rehabilitation of these structures are time
consuming and costly.
•By adding polypropylene fibers into the concrete, the plastic shrinkage cracks
of concrete at the early age reduced and it can also reduce the surface
bleeding and settlement of aggregate of fresh concrete, which can prevent the
formation of settling cracks.

4. •In this study various mixtures of polypropylene fiber of volume fractions of
0.15, 0.20, 0.25, and 0.30 was used for concrete mixes. Each series consists
of cubes as per IS standard. A series of tests were carried out to find out the
compressive strength at the age of 28 days. At the age of 28 days each
mixture were tested and analysed in order to find out the best efficient mixture
in favouring of strength characteristics of concrete mix.
•Polypropylene fibers are cheap and abundantly available.
•Due to its low density (0.9 gm/cc), high crystalline, high stiffness and excellent
chemical/bacterial resistance, is tactic PP is widely used in many industrial
applications such as nonwovens, industrial ropes, packaging materials,
furnishing products, etc.

5. NECESSITY
•Weight
•Plastic Shrinkage
Cracks
•Cost
•Permeability
•Absorption of water,
chemicals & dusting
•Corrosion
INCREASES
DECREASES
•Durability
•Anti-breaking capacity
•Abrasion Resistance
•Fire Resistance
•Strength

6. OBJECTIVES
OF PROJECT
To compute the effect on compressive strength of M20 mix
concrete due to Polypropylene fibre.
To carry out experimental investigations for comparative
study with varying Polypropylene fibre and water-cement
ratio.

7. LITERATURE
REVIEW
Author’s Name Research Paper Experimental Work
Gursharan Singh Effect on Compressive strength
of Concrete by Addition of
Polypropylene Fibre M20 Grade
of Concrete.
Compressive strength, Flexural
Strength & split Tensile Strength of
Concrete.
G.S Chewl et.al, 2017 Mechanical & Chemical
Properties and Polypropylene
Fibre is Reinforced Concrete
from Composites Parts
Flexural Strength & split Tensile
Strength of Concrete.
Prof. Sanjay
Gupta et.al, 2017
The structural is pozzolanic
ordinary cement potential
acting from by grid fibre
component
Compressive strength, Flexural
Strength & split Tensile Strength of
Concrete.

8. Oza, et. al, 2015 Mechanical properties of hybrid
fibre reinforced concrete
Cube compressive strength, Split
tensile strength of Concrete.
Pickering 2014 Performance of Polypropylene
Fibre Reinforced Concrete
Flexural Strength & split Tensile
Strength of Concrete.

9. METHODOLOGY
Preparation of Mix
Mixing of Materials
Addition of Water
Casting of Samples
Curing of Specimens

10. MATERIALS
REQUIRED
CEMENT
COARSE
AGGREGATES
FINE
AGGREGATES
POLYPROPYLENE
FIBER
WATER
POLYPROPYLENE
FIBER CONCRETE

11. CEMENT
•The cement used was Ordinary Portland Cement of 43 Grade.
•The cement has a specific gravity of 3.15.
•The physical properties are confirming to IS: 12269-1987 is given in Table 1.
Table 1: Physical Requirements for OPC, 43 grades
Sl No. Characteristics Requirements
1. Fineness, m²/kg, Min 225
370 for 43 grade
2. Setting Time:
a) Initial, min, Min 60
b) Final, min , Min 120
3. Compressive Strength, MPa
a) 7 days 15
b) 28 days 20

12. COARSE AGGREGATES
•Coarse aggregates used in this study are the crushed aggregates. The commercial
stones are quarried, crushed and graded. These are mainly the crushed angular granite
metal stones.
•The sizes of 20mm and 10mm are used.
•The specific gravity and water absorption is given in table 2 conforming IS 2386 (part
iii)- 1963.
Table 2: Physical properties of Coarse Aggregates
Physical
Property
20mm 10mm
Specific Gravity 2.883 2.878
Water Absorption 0.40 0.87

13. FINE AGGREGATES
•Fine aggregate used in the study is river sand confirming to zone III (IS: 383 -1970).
•Specific gravity and water absorption value (IS: 2386 (Part-iii) 1963) of sand used was
2.605 and 1.23% of wt. respectively.
•Limits of grading zone III is given in Table 3.
Table 3: % passing for Fine Aggregates
IS Sieve Designation % passing for Grading
Zone III
10mm 100
4.75mm 90-100
2.36mm 85-100
1.18mm 75-100
600µ 60-79
300µ 12-40
150µ 0-10

14. POLYPROPYLENE FIBER
•The fibres used were fine polypropylene monofilaments .
•It is available in 3 different sizes i.e. 6mm, 12mm and 24 mm.
•In the present investigation 12mm fiber length is used . The physical properties are
given in Table 4.
Table 4: Physical Properties Of Polypropylene Fibers
PARAMETERS SPECIFICATIONS
Size 12 mm
Melting point 170°C
Tensile Strength 390-590 MPa
Specific Gravity 0.91
Water Absorption 0

15. Potable water is used for mixing and curing from the water supply network system as it
was free from the suspended solids and organic material, which might have affected the
properties of the fresh and hardened concrete

16. MIX DESIGN
•The Concrete mix design has been carried out for various proportions as per IS 10262:
2009.
• 672kg/m³• 170kg/m³
• 1335.6kg/m³
•The ratio of water added to the cement was w/c = 0.42.
• 402.3kg/m³
CEMENT COARSE
AGGREGATES
FINE
AGGREGATES
WATER

17. FRESHLY PREPARED PP FIBER CONCRETE

18. MIX PROPORTION
The mix proportion was obtained for various percentages of polypropylene fiber i.e.,
0.10%, 0.20%, 0.50%, 1.0% and 1.5% replacement for Ordinary Portland Cement. In the
first trial, water content was maintained constant. However in the second trial water
/cement ratio was maintained constant. The mix proportions for various batches for trial I
& II given in Table 5 & 6:
Table 5: Details of Mix Proportions- Trial I Table 6: Details of Mix Proportions- Trial II
PP
Fibre
conten
t
(%)
Ceme
nt
(kg/m³)
Fine
Aggreg
ates
(kg/m³)
Coarse
Aggreg
ates
(kg/m³)
Water
(kg/m³)
0.10 402.3 672 1335.6 165
0.20 401.90 672 1335.6 165
0.50 401.10 672 1335.6 165
1.0 398.29 672 1335.6 165
1.5 396.27 672 1335.6 165
PP
Fibre
content
(%)
Cemen
t
(kg/m³)
Fine
Aggreg
ates
(kg/m³)
Coarse
Aggreg
ates
(kg/m³)
Water
(kg/m³)
0.10 401.3 675 1345.5 170
0.20 400.05 675 1345.5 170
0.50 401.50 675 1345.5 170
1.0 401.00 675 1345.5 170
1.5 400.50 675 1345.5 170

19. TEST ON SPECIMENS
1. COMPRESSION TEST
In this investigation we use cubical moulds of size 15 cm x 15cm x 15 cm.
Concrete is
poured in the
cast iron
moulds
Compacted
properly by
tamping rod of
standard size
or by vibration
Stored at
temperature
(15° -25°) &
relative
humidity of
90% is
maintained
Demoulded
after 24 hrs &
stored in water
for curing
After 7 & 28
days
specimens are
tested by CTM
Load at the failure
COMRESSIVE STRENGTH =
Area of Specimen
Load should be
applied gradually
at the rate of 140
kg/cm² per minute
till the specimens
fails

20. Compression Strength (MPa)
PP Fiber Content
(%)
7 Days 28 Days
0.10 13.50 22.03
0.20 14.05 24.05
0.50 15.00 24.06
1.0 14.60 24.00
1.5 13.50 23.03
Compression Strength (MPa)
PP Fiber Content
(%)
7 Days 28 Days
0.10 12.75 21.10
0.20 13.20 22.25
0.50 14.30 23.70
1.0 14.85 23.5
1.5 15.00 22.75
TABLE 7: COMPRESSIVE STRENGTH FOR TRAIL I
Table 8: Compressive Strength for Trail II
Compression Testing
Machine

21. 2. CONCRETE SLUMP TEST
This test is performed to check the consistency of freshly made concrete. The slump test
is done to make sure a concrete mix is workable.
The slump cone is a metal
mould in the shape of the
frustum of cone which is
open at both ends with a
base diameter of 200 mm (8
inches), a top diameter of
100 mm (4 inches), and a
height of 300mm (12
inches).
Fill the cone in
3 layers. Each
layer is tamped
25 times by rod
Remove
excess
concrete from
top of the cone
Immediately lift
cone vertically
with slow and
even motion
Invert the
withdrawn
cone & place
next to
slumped
concrete
Measure the
amt. of slump
from bottom to
top of slumped
cone
Rod dimension:
610 mm long bullet
nosed metal rod of
16 mm in diameter

22. PP Fiber Content
(%)
Slump values
(mm)
Slump Type
0.10 82 Normal
0.20 80 Decrease
0.50 75 Decrease
1.00 50 Decrease
1.50 30 Decrease
Types of Concrete Slump
Table 9: Slump Tests Values

23. 3. UNIT WEIGHT OFCUBES
Tests to study the variation of unit weight of the cube were conducted. The table10
shows the details about the unit weight of the cube with the increase in the percentage
of the polypropylene fibre content in concrete.
PP Fiber Content
(%)
Wt of the
Cube (kg)
Unit Wt of The
Cube (kg/m3)
0.10 790 2401
0.20 870 2405
0.50 810 2408
1.00 795 2406
1.50 890 2402
Table10: Unit Weight of Cubes

24. 4. POROSITYTEST
Water absorption test or the porosity test was carried out the percentage water
absorption was measured. The table11 shows the details about the water absorption test
carried out.
PP Fiber
Content (%)
Avg. Dry wt
(g)
Avg. wet wt
(g)
Water
Absorbed (g)
Percentage
Water
Absorption
%
0.10 700 790 90 11.40
0.20 790 870 80 9.20
0.50 720 810 90 11.11
1.00 705 795 90 11.30
1.50 810 890 80 9.00
Table 11: Water Absorption by Cubes

25. •Pavements and guard rails of highways and expressways
•Airport runway and parking apron
•Sprayed concrete at the wall surface and top of tunnel and mine revetment
•Major structure of bridge and deck
•Composite floor in building constructions
•Waterproof layer, floor, inner & outer wall of industrial and civil constructions
APPLICATIONS

26. REFERENCES
•IS 516: 1959 Method of test for strength of concrete
• IS 2386 (Part VIII): 1963Methods of Test for Aggregates for Concrete.
•IS 383:1970, Specification for coarse and fine aggregates from natural sources for concrete
• IS 10262:2009 Concrete Mix Proportioning- Guidelines.
•Aly T, Sanjayan J G and Collins F (2008),“Effect of Polypropylene Fibers on Shrinkage and
Cracking of Concretes”, RILEM, Materials and Structures, Vol. 41, pp. 1741-1753, DOI
10.1617/s11527-008-9361-2.
•Rana A. Mtasher, Dr. Abdulnasser M. Abbas, Najaat H. Ne’ma (2011) “Strength Prediction of
Polypropylene Fiber Reinforced Concrete”, Eng. & Tech. Journal, Vol. 29, No. 2, pp 305-311,
2011.
• J.A. Larbi and R.B. Polder “Effects of Polypropylene fibers in concrete: Microstructure
after fire testing and chloride migration”, HERON Vol. 52, No. 4, pp 289-305, 2007.
• Google search for images.

28. Code Referred: IS: 516 – 2002
Flexure
The state of being flexed (i.e. being bent)
Flexural strength
It is also known as modulus of rupture, bend strength, or fracture
strength, a mechanical parameter for brittle material, is defined as a
material's ability to resist deformation under load.
The flexural strength represents the highest stress experienced
within the material at its moment of rupture.
When an object formed of a single material, like a wooden beam or
a steel rod, is bent, it experiences a range of stresses across its depth.
At the edge of the object on the inside of the bend (concave face)
the stress will be at its maximum compressive stress value.
At the outside of the bend (convex face) the stress will be at its
maximum tensile value.

29. These inner and outer edges of the beam or rod are known as the 'extreme
fibers'.
Most materials fail under tensile stress before they fail under compressive
stress, so the maximum tensile stress value that can be sustained before the
beam or rod fails is its flexural strength.
Apparatus Required
 Flexural Strength testing machine / Universal Testing machine
 Balance
 Scale
Formula
The flexural strength of the specimen expressed as the modulus of rupture
kg/cm2
Where
b = measured width of the specimen (cm)
d = measured depth of the specimen at the point of failure (cm)
l = Length of the span on which the specimen was supported (cm)
P = Load applied (kg)

31. Apparatus
The testing machine may be of any reliable type of sufficient
capacity for the tests.
The permissible errors shall be not greater than ± 0.5 percent of
the applied load where a high degree of accuracy is required and not
greater than ± 1.5 percent of the applied load for commercial type of
use.
The bed of the testing machine shall be provided with two steel
rollers, 38 mm in diameter, on which the specimen is to be
supported, and these rollers shall be so mounted that the distance
from centre to centre is 60 cm for 15.0 cm specimens or 40 cm for
10.0 cm specimens. The load shall be applied through two similar
rollers mounted at the third points of the supporting span, that is,
spaced at 20 or 13.3 cm centre to centre.
The load shall be divided equally between the two loading
rollers, and all rollers shall be mounted in such a manner that the load
is applied axially and without subjecting the specimen to any
torsional stresses or restraints.

32.  The value of the modulus of rupture (extreme fibre stress in
bending) depends on,
- the dimension of the beam and
- the manner of loading.
 The systems of loading used in finding out the flexural tension are
- central point loading and
- third point loading.
 In the central point loading, maximum fibre stress will come below
the point of loading where the bending moment is maximum.
 In case of symmetrical two point loading, the critical crack may
appear at any section, not strong enough to resist the stress
within the middle third, where the bending moment is maximum.
 It can be expected that the two point loading will yield a lower
value of the modulus of rupture than the centre point loading.

33. S. No. Wt. Kg Ppf
%
Size in
mm
Date of
casting
Date of
test
load Flexual
Strength
1 13121 0 700/150/150 08/12/2019 7/01/2020 35.00 6.22
2 12161 0.04 --- --- --- 36.60 6.40
3 11361 0.08 --- --- --- 36.85 6.60
4 12621 0.12 --- --- --- 36.15 6.50

34. The following figure shows the modulus of rupture of beams of different
sizes subjected to centre point and third point loading.

35. Procedure
Test specimens stored in water at a temperature of 24° to 30°C for
48 hours before testing, shall be tested immediately on removal from the
water whilst they are still in a wet condition.
The dimensions of each specimen shall be noted before testing.
No preparation of the surfaces is required.
Placing the Specimen in the Testing Machine
The bearing surfaces of the supporting and loading rollers shall be
wiped clean, and any loose sand or other material removed from the
surfaces of the specimen where they are to make contact with the rollers.
The specimen shall then be placed in the machine in such a manner
that the load shall be applied to the uppermost surface as cast in the
mould, along two lines spaced 20.0 or 13.3 cm apart.
The axis of the specimen shall be carefully aligned with the axis of
the loading device.

36. No packing shall be used between the bearing surfaces of the
specimen and the rollers.
The load was then applied without shock and increasing
continuously at a rate such that the extreme fibre stress increases at
approximately 7 kg/sq cm/min, that is, at a rate of loading of 4KN per
minute for 15 cm specimen and 1.80KN per minute for 10 cm specimen.
The load was increased until the specimen failed and the
maximum load applied to the specimen during the test was recorded.
The appearance of the fractured faces of concrete and any
unusual features in the type of failure were also noted. The flexural
strength of the specimen expressed as the modulus of rupture was the
found from the formula,
If the fracture initiates in the tension surface within the middle
third of the span length.

37.  If the fracture occurs in the tension surface outside the middle third
of the span length, by not more than 5% of the span length and
discard the result if it is more than 5%.

38. The following information shall be included in the report on
each specimen:
a) identification mark,
b) date of test,
c) age of specimen,
d) curing conditions,
e) size of specimen,
f) span length,
g) maximum load,
h) position of fracture (value ‘a’),
j) modulus of rupture (kg per sq cm), and
k) appearance of concrete and type of fracture if these are
unusual.

39. SPLIT TENSILE STRENGTH

40. TENSILE STRENGTH
• Tensile strength is one of the basic and important
properties of concrete. A knowledge of its value is
required for the design of concrete structural elements.
• Its value is also used in the design of prestressed concrete
structures, liquid retaining structures, roadways and
runway slabs.
• Direct tensile strength of concrete is difficult to
determine; recourse is often taken to the determination
of flexural strength or the splitting tensile strength and
computing the direct tensile.

41. WHAT IS SPLIT TENSILE STRENGTH TEST?
A method of determining the tensile strength of
concrete using a cylinder which splits across the
vertical diameter. It is an indirect method of testing
tensile strength of concrete.

42. WHY WE ARE GOING FOR SPLIT
TENSILE TEST?
• In direct tensile strength test it is impossible to apply true
axial load. There will be always some eccentricity present.
• Another problem is that stresses induced due to grips. Due to
grips there is a tendency for specimen to break at its ends.

43. TEST SPECIMENS
Cylinder
• The length of the specimens shall not be less than the diameter and
not more than twice the diameter. For routine testing and
comparison of results, unless otherwise specified the specimens
shall be cylinder 150 mm in diameter and 300 mm long.

44. MAKING AND CURING TEST
SPECIMEN
• The procedure of making and curing tension test specimen in
respect of sampling of materials, preparation of materials,
proportioning, weighing, mixing, workability, moulds, compacting
and curing shall comply in all respects with the requirements given
in IS 516.
Sampling of Materials
• Representative samples of the materials of concrete for use in
the particular concrete construction work shall be obtained
by careful sampling.
• Test samples of cement shall be made up of a small portion
taken from each of a number of bags on the site. Test samples
of aggregate shall be taken from larger lots.

45. PREPARATION OF MATERIALS :
• All materials shall be brought to room temperature, preferably
27°±3°C before commencing the tests.
• The cement samples, on arrival at the laboratory, shall be
thoroughly mixed dry either by hand or in a suitable mixer in such a
manner as to ensure the greatest possible blending and uniformity
in the material, care being taken to avoid the intrusion of foreign
matter. The cement shall then be stored in a dry place, preferably
in air-tight metal containers.
• Samples of aggregates for each batch of concrete shall be of the
desired grading and shall be in an air-dried condition. In general,
the aggregate shall be separated into fine and coarse fractions and
recombined for each concrete batch in such a manner as to
produce the desired grading.

46. WEIGHING
• The quantities of cement, each size of aggregate, and water for
each batch shall be determined by weight, to an accuracy of 0.1
percent of the total weight of the batch.
Mixing Concrete
• The concrete shall be mixed by hand, or preferably, in a laboratory
batch mixer, in such a manner as to avoid loss of water or other
materials. Each batch of concrete shall be of such a size as to leave
about 10 percent excess after moulding the desired number of test
specimens.

47. MOULDS
Cylinders
• The cylindrical mould shall be of 150mm diameter and 300mm
height. Similarly the mould and base plate shall be coated with a
thin film of mould oil before use, in order to prevent adhesion of
the concrete.

48. TEST FOR SPLIT TENSILE STRENGTH
AIM:
To determine the splitting tensile strength of concrete
specimen.
Apparatus:
1. Weights and weighing device.
2. Tools, containers and pans for carrying materials &
mixing.
3. A circular cross-sectional rod (φl6mm & 600mm length).
4. Testing machine.
5. Three cylinders (φ150mm & 300mm in height).

49. • 4- A jig for aligning concrete cylinder.
The jig for aligning concrete cylinder and bearing strips

50. PROCEDURE:
1. Prepare three cylindrical concrete specimens.
2. After molding and curing the specimens for seven days in
water, they can be tested. The cylindrical specimen is
placed in a manner that the longitudinal axis is
perpendicular to the load.
3. Two strips of nominal thick plywood, free of imperfections,
approximately (25mm) wide, and of length equal to or
slightly longer than that of the specimen should be
provided for each specimen.
4. The bearing strips are placed between the specimen and
both upper and lower bearing blocks of the testing
machine.

51. 5.The load shall be applied without shock and
increased continuously at a nominal rate within the
range 1.2 N/(mm2/min) to 2.4 N/ (mm2/min).
6. Record the maximum applied load indicated by the
testing machine at failure. Note the type of failure
and appearance of fracture.

52. Computations: Calculate the splitting tensile
strength of the specimen as follows:
T = 2P
πLd
Where:
T : splitting tensile strength, kPa
P : maximum applied load indicated by testing
machine, kN
L : Length, m
d : diameter, m

53. RESULT :
• It is found that the splitting test is closer to the true
tensile strength of concrete it gives about 5 to 12%
higher value than the direct tensile strength test.
S. No. Wt. Kg Ppf
%
Size in
mm
Date of
casting
Date of
test
load Flexual
Strength
1 11431 0 150/300 08/12/2019 7/01/2020 195.01 2.75
2 12438 0.04 --- --- --- 214.03 3.02
3 12638 0.08 --- --- --- 224.00 3.16
4 12670 0.12 --- --- --- 229.00 3.23

54. Advantage of using this method:
• Same type and same specimen can also be used for
compression test.
• It is simple to perform and it gives uniform results
than the other tension tests like ring tension test and
double punch test.

55. THANK YOU