D. Previous Contamination can affect the bond of the resinous flooring and must be removed. Types of contamination are:
1. Oil, grease, or food fats can usually be burned off with a flame gun or removed with a commercial degreasing compound or solvent.
2. Curing compounds, sealers, and other laitance are best removed mechanically with:
a. vacuum shotblasting
c. sand blasting
E. Present Condition
1.Test for moisture: Coating system bond failures on slabs on grade and elevated/lightweight concrete caused by moisture vapor transmission are the industry's largest single problem and result in extreme frustration from owners, clients, and contractors. Epoxy.com recommends testing for moisture vapor transmission. The recognized methods are:
a. ASTM-F-1869 – Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride: The maximum allowed water/vapor transmission rate is 3 pounds per 1,000 square feet per 24 hours.
b. ASTM F-2170 – Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using In Situ Probes: This test measures the relative humidity in the slab below the surface. If taken over a period of time, it will show the rate of drying in the slab. The maximum relative humidity should be below 80%.
c. ASTM-D-4263 – Plastic Sheet Test: This test gives an indication that moisture may be present.
2. Moisture related failures can be prevented through:
a. Placing new concrete over an efficient vapor barrier.
b. Testing for moisture vapor transmission as prescribed above prior to resinous flooring application.
c. Applying a moisture vapor transmission reduction system where moisture content is too high for successful resinous flooring applications.
3. A clean surface is necessary to establish a strong bond between the resinous flooring and concrete.
4. Resinous flooring systems are only as sound as the concrete they are applied to. All unsound concrete should be repaired or replaced prior to resinous flooring applications. Consult your EpoxySystms’ Technical Service Department for specific information.
5. Resinous flooring materials should be applied to level concrete substrates. Grind or fill high and low spots prior to application.
6. Repair cracks prior to resinous flooring applications.