When testing the moisture content in non wood materials such as concrete a relative scale of 0 to 100 is often used where 0 is bone dry and 100 is saturated.
Measuring moisture content in concrete walls.
You see the cacl test and most other concrete moisture testing procedures employ methods such as the plastic sheet application only measure moisture escaping from the surface of the concrete slab.
Additionally some meters also offer a third scale for readings of gypsum.
Moisture meters include visual led indicators related to the percent reading on the scale for dry moderate and saturated or wet readings.
In 2016 the society for protective coatings sspc expects to publish a new guidance document field methods for the determination of moisture in concrete and masonry walls and ceilings that will describe the types of instruments used for determining moisture content of walls prior to painting including recommended test frequencies.
These scale readings can range from 0 2 to 50 moisture content.
The test is performed by sealing an insulated box to the concrete and measur ing the relative humidity inside the box with a calibrated capacitance based humidi ty gauge.
There are three standard methods for measuring concrete moisture.
Since we know that moisture within a slab varies by depth any moisture test that only measures moisture at the surface can t give you consistently reliable usable results.
Look at the wall surface carefully.
To test for moisture inside the walls start with manual tests and proceed to moisture meters.
In the wood scale the meter can detect moisture accurately over a range of 6 mc to 40 mc.
This is a relative scale.
Therefore measuring rh levels at 40 depth of the slab 20 depth if drying on two sides is more representative of the overall humidity conditions of the concrete.
Structural and safety hazards such as mold rot and decay are all potential consequences of elevated moisture levels in these materials.
Often more than one method is used to get an accurate reading of actual moisture content.
A separate reference scale setting can be used for getting qualitative readings of moisture in other wall materials like plaster.
Under this method you ll use a thermo hygrometer with in situ probes along with a series of prepared holes to get readings of relative humidity deep in the concrete slab.
According to astm f2170 when drying concrete slabs have lower moisture levels near the surface and higher levels towards the bottom of the slab.
When measuring moisture in concrete the best and most reliable method is to use the astm f 2170 testing method.
The ability to detect moisture accurately in both wood and drywall makes this device particularly suited for building inspection work.
Check for surface discoloration such as yellowing material.
How concrete hardens and dries concrete is manufactured by mixing cement aggregates such as sand and gravel and water.
