Concrete has a peculiar characteristic in that it may look smooth and even outwardly, but at the microscopic level it actually has an uneven and irregular surface. This is because concrete is a mixture of sand, slag, ash, gravel and other mixed aggregates, and as such, it is riddled with ridges and tiny crevasses that makes for an uneven profile. Depending on the quality of the concrete mixture, the degree of roughness in the surface profile can vary in concrete.
A rougher profile causes more air to be trapped during industrial floor coatings application. The trapped air will seek an outlet in whichever direction when displaced by a film of industrial floor coatings, sometimes merging with other vapors coming from other parts of the coated surface. When the combined air is strong enough to break free to the surface, blister-like pinholes appear.
To solve this cause of pinholes, abrasive blasting should be performed during surface preparation, to smoothen the irregular surface. A more even surface will remove ridges or pockets where air can be trapped during industrial floor coatings application. Another solution is to soak the surface with water prior to actual coating, which displaces air early on, before they are trapped during coating.
Another solution involves applying an epoxy formulation to fortify the concrete surface prior to industrial floor coatings application, which displaces air by tightly sealing the concrete surface.