Assignment 29819

There are two ways to estimate the
strength of the concrete, and both of the ways were applied and tested in the
experiment. The rst method is a non-destructive way to evaluate the strength
of the concrete digitally without smashing it. First, by using a Schmidt hammer
either horizontally or vertically downward or upward, a plunger hits the surface
and immediately shows on the screen the strength value. The procedure was
repeated for ten times and then the average of rebound numbers is calculated to
get the closest number to the real strength of the concrete which was 39.2MPa
(for MegaPascal). As it is known that the higher the rebound number is the
stronger the concrete is. As for the second way to nd the strength of the
concrete is a destructive method by using several equipment. At the beginning, a
Vernier caliper was used to calculate from a at surface at two di erent points of
a sample which is a concrete cube the width, depth, and height, and then
calculate the average of each one of them. Second, we nd the mass of the cube
by using a digital balance which was 2.929 kg, hence, we found the density by
using mathematical equations and converting the measurements to the needed
units such as Density= Mass÷Volume (which is W×D×H). Then, we nd the

compression failure load by using the Compression machine that crushes the
concrete completely at a speci c point and the number does not change which

was 320.6 kN (for kiloNewton). Last, the compressive strength of the cube can
be calculated by an equation F÷A (Compression failure load÷ Area) where the

unit of it is MPa.

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Conclusion

To reach to our purpose of calculating the compressive strength of
the concrete using di erent methods .We used the destructive and
non-destructive methods. As what is mentioned in the previous pages, for
the destructive method a compression machine was used, as for the
non-destructive method the electronic Vernier caliper and the Schmidt
hammer were used. Both of these methods were tested against a
hardened concrete block.

After testing the rst method that we used “Non Destructive Tests (NDT)
“we concluded that it has many advantages such as time saving, testing
can be rehashed, and enables continuous checking of the execution of the
structure. On the other hand, the one disadvantage was noticed is
Strength properties are not measured speci cally. Hence, it needs
adjustment.

In addition, after using the second method, we concluded the advantages
and disadvantages of destructive testing. The advantage of the
destructive testing is that it allows us to test di erent mix designs to
accomplish required strength. In the opposite side, the rst disadvantage
of this testing is that it is costly, time consuming, and specimen do not
actually represent actual structures.