Moisture in materials
Concrete strength depends markedly on water to cement ratio in the mixing process. When producing concrete the moisture content of aggregates must be known to fractions of per cent to minimise variability in concrete quality and to enable optimal usage of cement. Careful proportioning and mixing of the ingredients are crucial to producing a strong, durable concrete. Our main product in the segment of Moisture in materials is optical moisture sensor WCM411.
Water Content Monitor WCM411
Water content monitor WCM411 is an outstanding optical moisture sensor designed for detecting moisture content of concrete aggregates. The sensor embeds a micro-processor and uses LED’s as light sources. It provides a 4…20mA current loop output for process automation systems and an RS232 serial interface for maintenance and monitoring.
Moisture content is determined as percentage of water by weight of dry aggregate. The sensor is most optimal when used above conveyors or silo feeders to detect moisture content in moving samples.
WCM411 sensor highlights
- Non-contacting remote measurement
- Stable performance
- Long life-time
VipuNET software is provided with the WCM411
Frequently Asked Questions – Moisture in Materials
Why does aggregate moisture content need to be measured? The moisture in aggregate is part of the total water in the concrete mix. If it is not measured, the water-cement ratio varies from batch to batch — and so does the strength and quality of the concrete. In structural applications such as foundations, columns, and load-bearing slabs, this variability is not acceptable. Continuous measurement keeps batching under control and ensures every batch meets the same quality standard.
How does the WCM411 moisture sensor work? The WCM411 is an optical sensor that measures aggregate moisture without physical contact. Positioned above a conveyor belt or silo feeder, it emits light toward the moving material and analyses the reflected signal. Moisture content is calculated as a percentage of water by weight of dry aggregate. The measurement is continuous and real-time — not based on a spot sample taken at a single moment.
Can the sensor be integrated into a concrete plant’s automation system? Yes. The WCM411 provides a 4–20 mA current loop output, the standard interface for industrial process control systems. The moisture reading feeds directly into the batching system, which automatically adjusts the water addition to maintain the target water-cement ratio. An RS232 serial interface also supports monitoring and calibration through the included VipuNET software.
What materials and installation types is the WCM411 suitable for? The sensor is designed primarily for concrete industry aggregates — sand, gravel, and crushed stone. It is also suitable for monitoring moisture in asphalt plants, crushing and screening facilities, gravel pits, paper and cardboard mills, and other bulk material flows in process industries. Typical installation points are conveyor belts, silo feeders, and silo gate openings.
How often does the sensor need maintenance? The WCM411 is a non-contact remote sensing device, so it does not wear from abrasive material. In practice, the only regular action needed is occasional lens cleaning. Otherwise the sensor operates autonomously with automatic software updates.
How accurate is the measurement, and how is calibration handled? Calibration is carried out in the VipuNET software calibration window, where the sensor output is matched to the known moisture content of the specific material being measured. Calibration is material-specific, which ensures accurate results across different aggregate types. Once calibrated, measurement is continuous and stable.
Can one WCM411 monitor multiple silos or conveyors? One sensor monitors one material stream. If a plant has multiple silos or conveyors feeding different aggregate types, a separate sensor can be installed at each point. The VipuNET software supports monitoring of multiple sensors.
Where can I get more information or request a quote? Contact Teconer by email at info@teconer.com or by phone at +358 10 583 0020. You can also download the WCM411 datasheet, and read the peer-reviewed research article on optical moisture measurement published in Nordic Concrete Research.