Humboldt H-3033A Concrete Beam Tester - Manual (Page 4)

The most common usage of this unit will be to test 6x6" beams over a 16"
span. For this geometry:
(2)
The gauge measures in pounds force. It must be corrected for calibration error
and beam dimensions.
When beam and span dimensions vary from those in equation (2), the
calibration correction may be obtained from:
(3) Where P is the gauge reading
Operation 2
1. Center the test beam on the rollers.
2. Close the Flow Control Valve on the top of the cylinder.
3. Actuate the pump in a manner to achieve a smooth rate of applied load.
4. Record the gauge reading at break.
5. Measure the beam dimensions at the section of failure.
6. Calculate the modulus of rupture using equations (2) and (1) or (3).
Example: The gauge reads 5,400 lbf at break.
This corresponds to a modulus of rupture of 5,400/9 = 600 lbf/in 2
Per the calibration, the meter error at 5,400 is +0.5%.
The corrected load is 5,427 lbf.
The beam calipers as 6.1" deep, and 5.95" wide.
The modulus of rupture is:
Calibration
The unit is calibrated by measuring the load applied on a calibrated load cell.
The factory calibration is supplied at gauge readings of 10% FS, FS and 3
readings in between. Three load cell readings are averaged at each point to
establish the correction for each point.
The unit is not in full compliance with ASTM C293 since it uses a hand pump,
but numerous government agencies including Illinois DOT have found its results
acceptable.
2 Specific operation should follow the applicable specifications (e.g. ASTM C293). These operation
procedures are supplied as a guideline.