FACULTY OF ENGINEERINGDEPARTMENT OF CIVIL ENGINEERING
ECV 3014 CONCRETE AND ENGINEERING GEOLOGY LABORATORYSEMESTER 2
2013/2014LAB TITLE: FLEXURAL TESTDATE OF PRACTICAL: 1ST APRIL
2014GROUP NO: 2No.Matric NumberName
1173555Nur Rabiatul Adawiyah Binti Kamaruddin
2173259Nurfazira Binti Abdul Aziz
3176109Izzat Naim Bin Ibrahim
4175748Abuubakar Abdulkadir Hussein
NAME OF LECTURER: Dr. Azline Mohd NasirNAME OF TECHNICIAN: Mr.
Mohd Fairus IsmailNAME OF TEACHING ASSISTANT: Mr.Zain Aliuddin B.
Zain Alabidin
DATE OF SUBMISSION: 15thAPRIL 2014
Table of Content
ContentPage
1.0 Introduction
1
2.0 Objectives2
3.0 Procedure
3
4.0 Apparatus and Materials
4
5.0 Results5
6.0 Discussion
7
7.0 Conclusion
7
8.0 References
8
1.0 Introduction
Flexural strength, 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 transverse bending test is most frequently
employed, in which a specimen having either a circular or
rectangular cross-section is bent until fracture or yielding using
a three point flexural test technique. The flexural strength
represents the highest stress experienced within the material at
its moment of rupture. It is measured in terms of stress, sigma.
When an object formed of a single material, like a wooden beam or a
steel rod, is bent (Fig. 1), it experiences a range of stresses
across its depth (Fig. 2). 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. 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.
Figure 1
Figure 2
2.0 Objectives
In this experiment, the students are able to:
1. Understand the meaning of flexural strength.2. Differentiate
between the flexural strength and compressive strength.3. Conduct
the flexural test.4. Construct the water cement ratio versus
strength graph.
3.0 Procedure
1. The specimen is removed from the curing tank and the excess
moisture is wiped from the surface of the specimen. This test is
carried out in saturated condition on the scheduled date.2. The
specimen is weighed before testing and the nominal dimensions were
check and been recorded.3. The bearing surfaces of the supporting
and the loading roller is wiped cleans.4. The specimen is placed in
the machine. The center with the longitudinal axis of the specimen
is corrected at the right angles to the rollers.5. The load is
applied at a rate of 0.06 0.04 N/mm.s until the failure occurs.6.
The maximum load applied to the specimen is recorded. The flexural
strength, is calculated by the equation :
Where, F is the breaking load (N) d1d2 is the lateral dimensions
of the cross section (mm) L is the distance between the supporting
rollers (mm)
7. The flexural strength is expressed to the nearest 0.1
N/mm
4.0 Apparatus and MaterialsFig 3. Prism mould Hold the fresh
concrete to shape it before it hardened.
Fig 4. Weighing balanceTo weigh the prism concrete.
Fig 5. 100mm x 500mm x 100mm concreteAs a material to be tested
in this test.
Fig 6. Compressive machine test for prismTo give the flexural
force onto the concrete and to obtain the information.
5.0 Results
GroupSpecimen DesignationDimensionWeight (kg)Date of TestingLoad
(kN)Flexural Strength (N/mm2)Remark
1Prismatic100mm x 500mm x 100mm11.8271/4/201410.160.185 x
10-2
2Prismatic100mm x 500mm x 100mm11.8861/4/201413.830.252 x
10-2
3Prismatic100mm x 500mm x 100mm11.7741/4/201413.040.237 x
10-2
4Prismatic100mm x 500mm x 100mm11.6081/4/201411.220.2042 x
10-2
Table 1. Results taken from different groups
6.0 Discussion A flexure test produces tensile stress in the
convex side of the specimen and compression stress in the concave
side. This creates an area of shear stress along the midline. To
ensure the primary failure comes from tensile or compression stress
the shear stress must be minimized. This is done by controlling the
span to depth ratio; the length of the outer span divided by the
height of the specimen. For most materials S/d=16 is acceptable.
Some materials require S/d=32 to 64 to keep the shear stress low
enough. The flexural strength is differed between water/cement
ratios. As we can see, group 2 which have 0.55 ratios have a
greater strength compare to the other groups. This means that too
much water or too less water can affected the strength.7.0
Conclusion In conclusion, we do the experiment to know the ability
of concrete to resist an applied bending force such as encountered
by concrete pavements or other slabs on ground. A determination of
the flexural strength is frequently necessary as part of the design
of concrete mixtures to check compliance with established
specifications or to provide information necessary to the design of
an engineering structure. In the flexural-strength test, a test
load is applied to the sides of a test beam. Although the test can
be performed upon beams sawed from existing concrete structures, it
is more commonly performs upon concrete that are cast for testing
purposes. The standard test concrete measures 100mm x 500mm x
100mm. This experiment was conducted in 14 days after moulding to
let it age enough.
We are looking forward to know many things about flexure
according the lab we have and what we have done as practical we
thing as a group it is necessary to know something the student or
who ever want to know something about concrete. 8.0 References
1.
http://www.ksdot.org/burConsMain/Connections/ConstManual/pdfact5/16_23.pdf2.
http://en.wikipedia.org/wiki/Flexural_strength3.
http://www.nrmca.org/aboutconcrete/cips/16p.pdf