Moisture [Concrete]

 

 

MH Sensor

 

Description

A "MH" sensor is designed to measure the humidity inside a concrete slab. Included within the MH sensor is a temperature sensor, designated as model "TH" or "XH". Data is automatically collected once every 15 minutes. The Moisture Humidity (MH) is a custom fabricated sensor consisting of a small digital humidity and temperature sensor mounted inside a plastic tube.

 

Manufacturer

The MH sensors at MnROAD were custom designed and fabricated by MnROAD staff. The sensor consists of a digital humidity and temperature sensor

mounted inside a plastic pen tube with one end sealed and the other covered by a GoreTex fabric to prevent liquid water from entering the tube. The digital humidity and temperature sensor, model SHT75. is manufactured by the Sensirion Company.

 

Location and Quantity

MH sensors have been installed in several PCC test cells, typically at multiple depths to measure moisture gradients within slabs.

 

Current Status

The most recent installation of these sensors took place in Cells 70-72.

 

MnROAD Database Table

Data is being collected automatically every 15 minutes over the life of each sensor. Data can be found in MnROAD database tables: MNR.MH_VALUES, MNR.XH_VALUES, MT_VALUES, TH_VALUES.

 

 

MP Sensor

 

Description

A "MP" sensor is designed to measure the water potential inside a concrete slab. Data was collected both manually and automatically. A Psychrometer (MP) sensor consists of two thermometers mounted within a ceramic screen bulb (to only allow passage of water vapor) used to determine relative humidity via the relationship between dew point and temperature.

 

Manufacturer

Wescor, Inc. psychrometer model PST-55-15-SF.

 

Location and Quantity

MP sensors have been installed in several PCC test cells, typically at multiple depths to measure moisture gradients within slabs.

 

Current Status

MP sensors are no longer used. Measurements and calibration were found to be difficult.

 

MnROAD Database Table

Data was collected both manually and automatically shortly after installation. Data will eventually be loaded into the MnROAD database table: MNR.MP_VALUES.

 

 

MR Sensor

 

Description

A "MR" sensor is designed to measure the moisture content inside a concrete slab. Included within the MR sensor is a temperature sensor, designated as model "RT". Data is automatically collected once every 15 minutes. The Moisture Resistance (MR) sensor is a gypsum block based (soil moisture) sensor that uses electrical resistance to determine moisture content.

 

Manufacturer

ELE EI23-7724 Soil Moisture Block manufactured by ELE International.

 

Location and Quantity

MR sensors have been installed in several PCC test cells, typically at multiple depths to measure moisture gradients within slabs.

 

Current Status

MR sensors ceased to function in 2008.

 

MnROAD Database Table

Data was being collected automatically every 15 minutes over the life of each sensor. Data can be found in MnROAD database tables: MNR.RM_VALUES, MNR.RT_VALUES.