Before applying load to the specimen, it
is very important to understand the operation
of the control valve on the pump.
The machine in this example has a Greenlee Hydraulic
Pump with a Greenlee flow control valve.
The pump uses Dextron III ATF as the fluid of
The reservoir should be 3/4 full of fluid.
The vent, located on the back of the reservoir,
should be open prior to testing.
The valve contains 2 levers and 1 stem.
The lever on the right side of the valve is
the pressure/release lever.
In the upright position (with the knob against
the motor) the pump will build pressure.
In the down position (with the knob against
the reservoir) the pump will release pressure
and allow the piston to retract.
The lever on the left is the rapid advance/controlled
rate lever. With the knob pull toward the
operator, and the release lever in the pressure
position, the pump is in rapid advance.
This means the piston will move rapidly. Care
must be taken when using the rapid advance function.
The piston only has 2 1/2 inches of stroke.
If left in the rapid advance position for too
long, the piston will overextend causing a release
in oil from the piston area. Immediately shut
off the pump and Call CSI at 724-867-6664
for proper instruction of how to eliminate this
The rapid advance lever is used only to position
the piston close to the sample for zeroing purposes,
or to preload the sample once zeroing has been
performed. Never use the rapid travel position
to test the cylinder to total failure. This
will provide inaccurate test results.
With the knob pushed back toward the pump
motor (all the way back) the pump will be in
the controlled rate position.
All the fluid will be sent through the stem
located in the center of the valve. This stem
will allow you to set the rate of loading for
ASTM C-39, for a 6 X 12 concrete cylinder, requires
th rate of loading to be 35 psi/sec +/- 7 psi.
Calculated in lbs, this comes out to 990 lbs
per second. +/- 200 lbs.
The stem in the center acts like a water spigot.
Counter-clockwise increases the rate of force
application per second. Clockwise decreases
Once the proper rate is achieved, you can leave
the stem at that setting at that setting and
the machine will continue to load at the proper
You are now ready to test your specimen.
Select the appropriate gauge for your test
using the criteria listed above in section two
of this document.
Turn on the pump and move the release lever
up to the loading position.
(This is the lever on the right.)
Pull the knob on the left toward you and move
the piston close to the top of the sample.
Push the knob back toward the motor when
you have achieved 1/4 inch of daylight space.
Tap on the gauge and turn the zero adjustment
until the needle is on the zero line of the
gauge. THIS IS CALLED FRICTION ZEROING.
Move the red needle to 10% of the gauge capacity.
Check centering of the specimen on the cylinder
and close the fragment guard (if so equipped).
Pull the knob on the left side of the valve
toward the operator and preload the specimen
to the point where the red needle is set (at
10% of the gauge capacity). Push the knob back
toward the motor in a swift action.
Adjust the stem in the center of the valve
until you have the loading rate at approximately
1000 lbs/sec. You can time the needle motion
by determining the 5000 lb intervals on the
gauge and setting the valve so that the needle
passes 5000 lb intervals in 5 seconds.
Continue loading the sample, adjusting the
stem slightly if necessary, until the specimen
Once you have achieved a load of more than
1/2 of the specimen's strength, do not continue
to adjust the stem. The specimen testing rate
will slow automatically when the specimen reaches
Be sure that the specimen has fully broken.
Small corner breaks are common with pad caps.
These corner breaks are not considered ultimate
failure breaks. Continue to run the machine
until you achieve a total failure of the sample.
Move the knob on the left to the down position.
Shut off the pump.
Record the position of the red pointer on the
gauge as your maximum force value.
Reposition the red pointer to 10% of the gauge
Remove all debris and wipe down cap bases.
You are now ready to test your next specimen.
Special Note: Tests made on the low gauge
require extra special attention to the zeroing
procedure. Failure to carry out the procedure
effectively will cause great differences in
ultimate load. This gauge is much more sensitive.
Friction zeroing of this gauge is very important.
Please follow the instructions carefully.