Testing Equipment

MOHS Hardness Test Kit

Mohs Concrete Tester

Concrete is made up of various elements of different hardness and densities that vary from region to region. Use of these picks is limited to providing a general guide for surface harness.

How to Test Concrete Hardness using a MOHS Scale

Concrete is made up of various elements of different hardness and densities that vary from region to region. Use of these picks is limited to providing a general guide for surface harness.

Steps to testing:

1. Start with a pick with a higher number than the surface being tested is believed to be. For beginners, start with pick #9 until more experienced and you have a general feel for the concrete in your area.
2. Grasp the pick in the same fashion as you would a pen and place the edge of your palm on the floor as if ready to write.
3. Reach forward with the pick and draw a 2” line towards you using the same downward pressure you would use if writing with a pen on paper.
4. You will notice the #9 pick will easily produce a scratch. Subsequent picks, will leave less and less of a scratch. Do NOT force any of the picks to scratch.
5. Continue down through the scale until you encounter the pick that will not scratch the surface. For example if #5 leaves a scratch but #4 does not, then the floor is about 4.5 on the MOHS scale.
6. Sometimes the metal from the pick will lay down and look like a scratch. A magnifying glass will help you to see the scratch or line left by the pick.
7. If you are unsure whether the pick left a scratch, lightly drag the pick perpendicular across the first line. If there is a scratch, you will feel the pick drop into the grove.
8. Always test in different locations of the floor in order to get a more accurate result. There may be more than one pour present in different areas of the floor, which may give widely varying results
9. Be alert for signs of micro-topping, self leveling or filling/patching compounds. Look at different colors, textures or possible edge delamination for clues.
10. To increase your knowledge of the aggregates used in your area, do a scratch test on individual stones that are exposed during the grinding, polishing process.
11. The picks should always be sharp and in good condition. There is a small stone in the kit that can be used for dressing the tip.
12. The picks have extremely sharp points. Care should be used when handling them.
13. Never place a loose pick in any pocket or article of clothing.
14. It must be remembered that the picks and instructions are only a guide and do NOT cover every possible situation.

North American Aggregate Classification Map