Instructions for Use

Operating instructions are provided with the MotarCheck II Mortar Durability Testing Instrument and can be downloaded here.

Procedure

The test procedure is set out in Australian Standard AS 3700-2011 Masonry Structures Appendix E (Appendix FA in AS 3700-2001). The following procedure is provided to assist in operating the MortarCheck II instrument when carrying out tests in accordance with the standard.

  1. Unfold the support legs to an even spacing around the probe.
  2. Set the instrument readout to the inch scale for maximum precision (displaying 3 places after the decimal point).
  3. Retract the spring and insert the spacer.
  4. Align the handle at the bottom so that the notch lines up with the top of the yoke.
  5. Loosen the two thumbscrews.
  6. Slide the instrument within its case until the probe rests lightly on the joint at the test location, while all three legs rest on the adjacent masonry units. Adjust legs as required to provide the most stable support.
  7. Tighten the thumbscrews to lock the instrument to its case.
  8. Remove the spacer to allow the spring to press the probe against the joint. This procedure ensures that there is 10mm spring compression at the commencement of the test.
  9. Hold the case firmly at the base around the thumbscrews. Do not hold or put pressure on the instrument readout plate.
  10. Give the probe 2 full turns, being careful not to exert any axial force on the probe.
  11. Zero the readout.
  12. Maintain the same firm hold on the case and give the probe 5 full turns as required by AS 3700.
  13. Record the reading for this location.
  14. Repeat for a total of five tests and average the results to obtain the Scratch Index.
  15. If required, convert the reading from inches to millimetres by either:
    a. multiplying by 25.4
    b. using the conversion table given in the instructions
    c. Excel spreadsheet available from here

Probe Test Record

The probe is subject to wear, which is known to increase the variability of results, and must therefore be changed after a maximum of 200 tests. A table is provided in the instructions to record each scratch index result (comprising five tests). The probe is changed after 40 results obtained (5 x 40 = 200).

To change probes, simply pull the existing one from the bit where it is secured magnetically and replace with a new one. A total of six probes are supplied with the MortarCheck II Mortar Durability Testing Instrument.