DynaCrete® International Inc.

It is never safe to assume that a concrete slab will always be dry because it has been dry…

Fact:

Alkali is never pure and rarely stable. It is made up of a combination of elements and almost always reacts with other elements.

We start with hydrogen, then lithium, sodium, potassium, rubidium, cesium and francium. Francium is radioactive with a half-life of only twenty minutes. The other five are very active alkali metals. Each element has electrons and molecules, which are always eager to take part in chemical reactions with other elements. The two most important alkali metals are sodium and potassium. We find a hint of them in potassium carbonate and sodium carbonate. Sodium makes up 2.6% of the earth's crust and potassium makes up 2.5%, yet we never see them. They are always found in combinations with other elements. Neither of them could remain pure in air or moisture.

Alkali is never pure and rarely stable. It is made up of a combination of elements and almost always reacts with other elements.

Efflorescence through cracked concrete
Efflorescence through cracked concrete (13K)

The increased use of concrete subfloors in direct contact with the ground makes more important than ever, the complete understanding of moisture and alkali inherent in these subfloors and their effects on paints and floor coverings.

Well known as the "alkali problem", this condition is primarily a problem of moisture. Alkali is present in every concrete slab and is more detrimental with moisture. On adequately ventilated, suspended concrete subfloor moisture is not present in troublesome quantities.

Where the slab is in direct contact with the ground or a poorly ventilated air space, moisture is brought up through the slab by capillary action. It dissolves the alkaline slats in the concrete and appears at the surface as a destructive alkaline solution causing spalling and efflorescence. (see related article on effloresence.)

Although moisture and alkali conditions may vary greatly, there is always sufficient moisture in the ground and alkali in concrete to present an "alkali problem" on subfloors affected by ground moisture. It is never safe to assume that a concrete slab will always be dry because it has been dry; moisture content may be small. When paint or floor coverings are applied, the moisture and alkali collects under the coverings. This often results in coverings buckling, warping, or separating from the concrete surface.

Recommendation:

We recommend DynaCrete® PIM+ to alleviate this problem. We can seal and waterproof the concrete to eliminate spalling and efflorescence, leaving clean pores and surfaces similar to "etching" on the surface to which paint, mastics or adhesives for floor covering can effectively secure a better bond. The destructive moisture attacking problems, which causes deterioration to the adhesives and paints will also be eliminated.

Efflorescence

Efflorescence on it's own is not a problem, until moisture is introduced. Moisture is a carrying agent that transports efflorescence through the concrete, thereby destroying concrete and steel inside the concrete which hold it together. 90% of your problem is moisture; this is where DynaCrete® PIM+ comes into play. As it penetrates into the concrete, it reacts with the alkali and forms a hydrostatic head, barring the migration of moisture. See article on Effloresence.

Not a simple problem to solve, therefore it's recommended that certified and trained applicators do this procedure to get you the best results you need and should demand.