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Concrete Moisture
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Glossary: Concrete Terminology

These definitions are intended to promote general familiarity with common terms of the concrete industry.

Admixture: a natural or manufactured chemical which is added to concrete before, or during, its mixing. Admixtures are often deployed to add special properties to concrete.

Ambient RH: the relative humidity surrounding a concrete slab. The RH of air in a room or in the open qualifies as ambient.

ASTM: American Society for Testing and Materials: a global body which develops voluntary consensus standards in construction.

Calcium Chloride testing: a moisture content assessment procedure which measures the water evaporation rate at the surface of concrete.

Cement: a substance which binds other materials together, such as aggregate and water, to form concrete.

Concrete: a composite mixture of cement, aggregate and water.

Concrete moisture meter: a measurement device which assesses the relative humidity level of concrete.

Curing: the process by which concrete hardens due to the chemical process of hydration.

Equilibration: the process by which the relative humidity of a building material, such as concrete, is balanced with the RH of its surrounding environment; also used to refer to the process of an in situ probe reaching similar or balanced conditions (temperature, moisture levels, etc) to the surrounding concrete.

Hydrostatic pressure: units of pressure which are created by a liquid when it is at rest.

In Situ probe: a sensor which must be embedded in a concrete slab (typically by drilling a hole into the slab and installing a sensor within a sleeve) in order to assess the slab’s moisture content (MC).

Leapfrogging: the act of moving concrete RH probes to several test places in a concrete slab without allowing sufficient time for the probes to equilibrate.

Moisture content (MC): the term used to describe the amount of water vapor within a concrete slab.

Multi-use probe: a relative humidity(RH) measurement device which contains a sensor and a separate plastic, cylindrical sleeve. Builders place the sleeve inside a hole drilled in concrete, then insert the sensor into to cylinder to measure concrete RH.  Multi-use probes can be re-calibrated in order to be re-used on another job site.

MVER: Moisture Vapor Emissions Rate which indicates the rate of moisture evaporation from the surface of concrete. MVER is a result of Calcium Chloride (CaCl)  testing.

Portland cement: a widely-used form of cement which hardens in contact with water to produce a water-resistant product.

Power troweling: the process of smoothing a concrete slab surface using motorized equipment.

Relative humidity (RH): the term used to describe the ratio of water vapor in the combined mix of air and water; relative humidity is also used to express the ratio of moisture content in concrete.

RH testing: a procedure which determines the amount of water vapor (or relative humidity) in concrete.

Service conditions: the point at which a building’s concrete slab is fully enclosed and the heating, ventilation and air conditioning (HVAC) systems are up and running.

Single-use probe: a relative humidity(RH) measurement device designed for use on a single job site. A single-use probe is typically skim-coated into the slab once testing is complete.

Slab temperature: the temperature of concrete below the surface of the slab.

Substrate: a structural reinforcement beneath a concrete slab; or, the concrete slab or subsurface directly beneath a flooring finish.

Vapor barrier: a building material, such as plastic or foil sheeting, which serve to slow (or retard) moisture’s permeation from external sources into a concrete slab.


If you notice any term related to concrete moisture that we’re missing, let us know!

Article by Cheryl Masters