Double, triple, quadrupling… the expected life cycle of concrete

Chemical bonding vS Adhesion

Ironically, it is not uncommon to hear the term “adhesion bond,” when in fact the phenomenon of adhesion does not include any actual chemical bonding. Adhesion is really just a coating’s ability to be “sticky.” This stickiness is sometimes due to a chemical trait that uses Van der Waals forces, a type of physics that basically means that two surfaces “like each other” and will stick together for a brief time while optimum conditions last. This is a temporary condition that rarely last long in industrial settings.

When a coating “adheres” at the surface interface of the concrete, there is an “adhesion zone” which is vulnerable to being damaged by the presence of humidity from under the slab, or cleaners and water from the cleaning process. In the presence of other chemicals, including simple water/humidity, the two surfaces may stop “liking each other” and the adhesion between the two surfaces dissolves away. Harsh cleaning chemicals generally accelerate this dissolving process. This is one reason epoxy and other plastic coatings delaminate from concrete surfaces. In reality, plastics cannot chemically bond to concrete, as their chemistries are too dissimilar. This is also a reason many coatings require the installation of a vapor barrier because the moisture is a known cause of failure.