The Moisture Measurement Blog

Moisture in Concrete, Free vs Bound Moisture

Water in concrete is presented in three stages: as free water held by capillarity, as absorbed water held by surface forces and as bound water held chemically. The ideal method of moisture measurement should quantify amounts of these three states, but this is a difficult task because moisture in concrete is not uniformly distributed, and moisture distribution varies with the exposure time (Li Chunqiu 2008). 

Using a pin moisture meter or a pinless moisture meter is not a good method for analyzing moisture in a concrete slab. These types of meters are not able to pick up the different types of water in concrete. The meter will measure all of the water in the slab not just the free water. The free water is what is going to affect the vapor emissions that will cause floor covering failure.

Measuring the moisture of a concrete floor is very hard because of the nature of concrete. The floor covering industry is always evolving and trying to incorporate a more accurate and efficient method for evaluating moisture in a concrete slab. Ten years ago, people were only doing the calcium chloride test when analyzing moisture in concrete. Today many manufactures and people in the floor covering industry have moved to using the RH in-situ probe method following ASTM F2170 standards. Lignomat has developed a system for measuring concrete following the ASTM F2170 guidelines. Please call if you are interested in purchasing.

→ Please click here to watch a more detailed video of how the system works.

Reference: Li Chunqiu, L. K. (2008). “Numerical analysis of moisture influential depht in concrete during drying wetting cycles.” Tshingua Science and Technology Vol 13, N°5: 696-701.

Lignomat’s RH BluePeg pobes are designed to comply with the latest ASTM F2170 standard. The stand-alone RH BluePeg probes with universal 3.5mm stereo connectors allow easy integration with other Lignomat’s measuring technologies.

You can select the handheld meter which best fits your
needs. For measuring concrete only, it could be the RH-only meter Ligno-Tec RH, because you do not need to measure wood. If you measure floorings, Ligno-DuoTec BW will be your best choice as it is a RH-pinless meter. With the Ligno-DuoTec BW you can measure wood moisture with pinless dual depth mode, relative humidity with RH Thermometer mode, and RH in-situ concrete moisture testing (ASTM F2170). While the Ligno-VersaTec covers all applications for pin, pinless and RH measurements. No matter which measuring mode you use, the Ligno-VersaTec gives superior results. It is a great tool for inspectors.

Please click the following links for more information about our RH Packages:
Concrete Package with Ligno-Tec RH (RH-KS)
Flooring Package with Ligno-DuoTec BW (BW-KS)
Inspector Package with Ligno-VersaTec (V2-KM) 

Besides handheld meters with RH Technology, Lignomat also offers:

On-site Data Loggers with RH Technology:
RH-only BL2: records RH in 30 s – 1day intervals.
RH and MC: records one RH and 3 wood moisture probes. Programmable for other materials.

Wireless transmitters in RH Technology:
Single RH transmitter
Single RH transmitter plus one MC probe