NEW ERA UNIVERSITYCOLLEGE OF ENGINEERING AND
TECHNOLOGYDEPARTMENT OF CIVIL ENGINEERING
CONSTRUCTION MATERIALS AND TESTING
LABORATORY MANUAL(2012 EDITION)
BYGERMAN B. BARLIS, DT
Laboratory Exercise No. 20
FLEXURAL STRENGTH OF CONCRETE BEAM
Name: Santos,Katrina Cassandra Date Performed:SEPTEMBER
12,2012
Course/Year: BSCE/4th YearDate Submitted:OCTOBER 2 ,2012
Section: Wed 8:30-11:30aInstructor: Bro. GERMAN B. BARLIS
Laboratory Exercise No. 20FLEXURAL STRENGTH OF CONCRETE BEAM
FINAL DATA SHEET
Table 19.1 Concrete Cylinder Properties
SampleIDPhysical Properties
b(mm)d(mm)L(mm)a(mm)P(N)MOR(MPa)
B1156152470-----47901.25
B2153152470-----63801.70
B3154152470-----70001.85
SET UP OF APPARATUS
We Placed the concrete beam on the support beam In UTM and set
the span to 18 inches.Load was applied continuously The maximum
load applied in failure was noted as well as the location of
failure from support
This is the failure on the concrete that we had testedSAMPLE
COMPUTATION
MOR
MOR(B1) = 1.25 Mpa
MOR(B2) = 1.70 Mpa
MOR(B3) = 185 Mpa
ANALYSIS AND INTERPRETATION OF DATA
In this laboratory exercise, we were able to emphasize and
learned the flexural strength of a sample concrete beam. From the
tabulation of data and results obtained , 3 samples were listed.
All samples used the concrete mixed having same proportion of sand,
cement, gravel and water but different data in mass, area and the
maximum load applied.As seen in the tabulated data, we gathered b,d
, and l to compute for the Modulus of rupture of each of the 3
sample. Every sample has an a failure on its midspan. B ranges from
153 mm to 156 mm, D has a constant measurement of 152 mm and L has
also a constant value of 470 mm. While in the recorded value for
the maximum applied load by the testing machine, Sample 3 has the
highest amount of P with 7000N and also has the highest amount of
Modulus of rupture which is 1.85 MPa. Sample 1 has the lowest value
for both Load applied and Modulus of rupture which are 4790N and
1.25MPa respectively. This only shows that Sample 3 has the highest
flexural strength among the 3 samplesSpecifications and
investigation of apparent low strengths should take into account
the higher variability of flexural strength results. Flexural tests
are extremely sensitive to specimen preparation, handling, and
curing procedure. Beam specimens are very heavy, and allowing a
beam to dry will yield lower strengths. Beams must be cured in a
standard manner, and tested while wet.A short period of drying can
produce a sharp drop in flexural strength. I observed that errors
maybe occur in the mixing of concrete, and also the quality of
aggregates, sand and cement contribute a high percentage of failure
in on the sample.
CONCLUSIONUpon the completion of this laboratory experiment, we
were able to comply on the objective which is to identify and
measure the concrete beam resistance in bending or flexure.
Concrete is a structural material which consists of Portland
cement, aggregate (sand and gravel), and water. Compressive
strength is the capacity of a material or structure to withstand
axially directed pushing forces, when the limit of compressive
strength is reached, materials are crushed. Compressive Strength of
Cylindrical Concrete is important to determine to require its
purpose such as to establish a strength-age relationship for the
concrete under .It is also essential for us, future Designers to
understand and learn that designing pavements use a theory based on
flexural strength. Therefore, laboratory mix design based on
flexure may be required, or a cement content may be selected from
past experience to yield the needed design Modulus of rupture .
Some also use MR for field control and acceptance of pavements.
Very few use flexural testing for structural concrete.
SAMPLE COMPUTATIONS
