Properly taken cube samples provide an accurate measurement of the strength of a pour and are required on many underlayment pours. Following the guidelines presented here when taking cube samples on site should ensure an accurate representation of the underlayment pour.
• Cube Mold
• Light Lubricant
• Clean Cloth
• Pitcher or clean container
• Mixing stick
Note: Care should be taken to ensure the sample taken is an accurate representation of the mix. Thoroughly clear the slurry from the hose before taking the sample.
Step 1 – Lubricate the Cube Form
Lubricate the form with a light lubricant to ensure the samples will release when fully cured. Wipe the form to remove any excess with a clean cloth.
Step 2 – Take a Clean Sample
Fill pitcher or other clean container with the current underlayment mix as needed from end of hose. (The sample should not be taken from any other sources).
Step 3 – Keep Sample Agitated
Use a clean mixing stick to keep sample agitated until it can be poured. This will prevent the aggregate from settling and providing an inaccurate test result.
Step 4 – Fill Cube Form
Fill each individual cube form to half with sample. Agitate each sample lightly and then fill each sample completely full. Do not scrape excess material from the top of the sample as this can cause the top to be concave, reducing the compressive strength when tested.
Step 5 – Agitate Cube Form
Lightly agitate each sample thoroughy to ensure that any voids or air pockets rise to the top. These voids can greatly reduce the tested strength of a sample.
Step 6 – Leave Cube Form Unmoved
The cube form should remain entirely undisturbed for at least 2 hrs until the sample is set. Any movement before the sample is set may negatively impact the test results.