Understanding the moisture content in concrete is a crucial step before applying any coatings, particularly epoxy resin floor coatings. RESINUS recommends the ASTM F2170 Relative Humidity (RH) test as the most reliable method for this purpose. This detailed guide will break down the ASTM F2170 process, ensuring it's easy to understand and execute.
Why Choose ASTM F2170?
ASTM F2170 is favored over other methods like calcium chloride tests due to its reliability and comprehensive approach. Unlike surface methods, which only measure moisture at the top layer of the concrete, the ASTM F2170 test assesses moisture levels more deeply and accurately, providing a true indication of the slab's overall condition. This is especially crucial for applying coatings like epoxy resin, where understanding the internal moisture is key for a successful application.
Identifying Test Locations
Selecting the right test locations is the first critical step. Use non-destructive impedance tests to identify areas with varying moisture levels. For grade-level slabs, ensure there's a vapor barrier beneath to prevent moisture ingress from the ground.
The ASTM F2170 Testing Process
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Strategic Drill Location Planning
- Plan your drilling locations methodically, ensuring coverage across the slab as per ASTM F2170 standards – three tests per 1000ft² and one additional test for every subsequent 1000ft².
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Drilling the Holes
- Drill dry and at a 90° angle. For slabs drying from the top, drill to 40% of the slab's thickness. For double-sided drying drill to 20% of the thickness.
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Preparing the Drill Holes
- Clean each drilled hole thoroughly to remove dust and debris, ensuring accurate test results.
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Installing Hole Liners
- Insert and seal liners in the holes, then wait for 24 hours to negate any heat impact from drilling on the readings.
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Inserting the RH Probe
- After 24 hours, place the RH probe in the liner. Temperature consistency between the probe and concrete is crucial for accurate readings. Allow approximately 5 minutes for the probe to reach temperature equilibrium before measuring.
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Interpreting the Results
- Remove the cap and quickly connect your moisture meter and observe the readings for stability. This gives a clear indication of the moisture condition within the slab.
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Recording Findings
- Document the RH levels, ambient conditions, and specific timestamps, adhering to ASTM F2170 documentation standards.
Addressing High Moisture Readings
If the RH test results exceed 85% RH, it's essential to take corrective action before applying any coatings. RESINUS suggests installing a Moisture Vapor Barrier Epoxy such as US100MVB, which effectively controls moisture vapor transmission up to 25lbs/24hr/1000 ft², exceeding ASTM F3010 standards. This step is critical to ensure the durability and effectiveness of the epoxy resin flooring.
By following these steps, you can accurately assess the moisture condition of a concrete slab. This ensures that the application of epoxy resin floor coatings by RESINUS or similar products is done under the best possible conditions, safeguarding the longevity and aesthetic of the flooring.
Note: Always refer to national standard guidelines for definitive and current procedures and specifications.