Means of controlling topical vapor emission and alkalinity
Topical moisture control can only be preformed by three means: penetrating liquids that enter into concrete pores, surface coatings that are bonded to the surface of the slab, and dispersive membranes that are also bonded to the surface but establish some sort of physical space between the concrete and flooring material or coating.
Penetrating liquids are either chemically-reactive products or mechanically-reactive products. Chemically-reactive products such as sodium and potassium silicate require calcium hydroxide in the concrete to react with in order to create a by-product to control moisture. Mechanical penetrates control moisture without dependence upon concrete chemistry.
Surface coatings can have a wide range of permeability depending upon material and applied density. In general, coatings like high solids epoxies will be too restrictive in controlling emission. Coatings must not reduce the emission value too quickly, or an interstitial condensation condition will fail the coating, just as it does with an epoxy flooring surface. A well engineered coating can be applied at varying thicknesses without total blockage of vapor.
Diffusive membranes are typically acrylic-based or cementitous. A properly engineered acrylic membrane system can employ fibermat to act as a reservoir for collected vapor gas. Acrylic membrane systems have the advantage of rapid, uniform installation and crack spanning, while cementitious membranes are less expensive, but can crack easily, resulting in failure.
Floor Seal Technology Mechanical Methods of Topical Vapor Emission & Alkalinity Control
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Penetrants |
Enters into concrete to stabilize humidity and immobilize mineral migration. | ||||
| What- Why- How- Where- |
a liquid that is capable of soaking into the concrete substrate.
to stabilize the internal humidity of slab and provide a primer for subsequent treatments.
by filling cavities with a semi-permeable, but mineral-restrictive agent.
On-grade as a stabilizing agent and primer for successive treatments. Used on suspended slabs for control of moisture contained in lightweight aggregate. |
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| Coatings | coats the concrete surface to suppress moisture vapor emission volume. | ||||
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What- Why- How- Where- |
a liquid with a viscosity capable of establishing a physical coating.
to suppress the volume of moisture reaching the surface.
by mechanically regulating permeability and reducing surface volume.
on-grade and suspended slabs with a low vapor transmission volume. |
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| Membranes | creates a physical layer on concrete surface to buffer the vapor pressure differential | ||||
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What- Why- How- Where- |
a physical cavity created upon the concrete surface.
to regulate the environment forces which create emission.
by creating a physical high humidity cavity and thermal barrier between the slab and surface thereby reducing vapor pressure as it disperses moisture volume laterally. on-grade and suspended slabs with a moderate vapor transmission and in conjunction with Penetrants and Coating in high vapor transmission conditions. |
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