Procedure of
Compression Test
Step1 – Preparation
: Check all the things you need are ready. Check concrete compression machine is a
checking order.
Step2 – Safety: Wear hand gloves and
safety goggles.
Step3 - Taking measurement: Take the
measurement of concrete specimens (which are sent to laboratory for testing).
Calculate the cross sectional area (unit should be on mm2) and put down on
paper. Do the same for each specimen.
Step4 - Start machine: Turn on the
machine. Place one concrete specimen in the centre of loading area.
Step5 - Lowering piston: Lower the piston
against the top of concrete specimen by pushing the lever. Don't apply load
just now. Just place the piston on top of concrete specimen so that it's
touching that.
Step6 - Applying load: Now the piston is
on top of specimen. It is the time to apply load. Pull the lever into holding
position. Start the compression test by pressing the zero button on the display
board.
Step7 - Increasing pressure: By turning
pressure increasing valve counter-clockwise, adjust the pressure on piston so
that it matches concrete compression strength value. Apply the load gradually
without shock.
Step8 - Test is complete: Observe the
concrete specimen. When it begins to break stop applying load.
Step9 - recording: Record the ultimate
load on paper displaying on machine's display screen.
Step10 - Clean the machine: When the
piston is back into its position, clean the creaked concrete from the machine.
Step11 - Turning off machine: Match your
record once again with the result on display screen. The result should still be
on display screen. And then turn off the machine.
Step12 - Calculate concrete compressive
strength: The result we got from testing machine is the ultimate load to break
the concrete specimen. The load unit is generally in lb. We have to convert it
in Newton (N). Our purpose is, to know the brick compressive strength.
We know, compressive strength is
equal to ultimate load divided by cross sectional area of concrete specimen. We
took the concrete specimen's measurement before starting the testing and calculated
cross sectional area.
Now we got the ultimate load. So we
can now calculate the brick compressive strength.
Compressive strength = Ultimate load
(N) / cross sectional area (mm2).
The unit of compressive strength will be N/mm2.
The unit of compressive strength will be N/mm2.
Normally 3 sample of concrete
specimens are tested and average result is taken into consideration. If any of
the specimen compressive strength result varies by more than 15% of average
result, that result is rejected
.
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