Moisture and Temperature Measurement for Sustainable Concrete
New sensor technology enables precise moisture and temperature measurement in bulk materials for sustainable concrete production, optimizing processes and reducing CO2 emissions.
Eco-friendly thanks to precise sensor technology
Concrete production faces the challenge of conserving natural resources and reducing CO2 emissions. One approach is the use of limestone powder or calcined clays as clinker substitutes. To efficiently process these new cements and additives and produce precisely differentiated concrete mixtures, adapted sensor technology is required. This technology records moisture and temperature at various points in the process chain. Particularly, the moisture content and temperature of individual raw materials such as cement, additives, and aggregates significantly influence concrete quality and must therefore be precisely monitored.
Microwave moisture sensors for ingredients of concrete
Moisture measurement is based on the dielectric method in the microwave range. The microwave moisture sensor is in direct contact with the measurement medium and penetrates at least 50 mm deep into the material. This allows for the detection of moisture not only on the surface but also deeper within the material. The result is high measurement accuracy due to the measurement of a large volume of bulk material. The sensors are typically installed below the silo outlets of mixing plants to measure the largest possible quantity online during dosing and ensure precise control.
Calibration and Use in Mixers
Sensor calibration is crucial, as moisture is determined indirectly via auxiliary variables. Moisture sensors must be calibrated under real conditions and with specific raw materials on-site. The readings of the microwave probes are linear over a wide range, simplifying calibration. Only two support points are needed for a calibration line, ideally in the middle moisture range of the material. For aggregates up to 32 mm, a robust measuring ceramic of the microwave moisture sensor can also be used directly in concrete mixers to determine the total water content of the batch.
