Description

 

 

What is a coarse aggregate moisture probe?

A coarse aggregate moisture probe is a fixed online sensor permanently installed in a production line to measure the moisture content of coarse granular materials continuously. It mounts inside a silo, hopper, or mixer, or on a conveyor belt, and feeds real-time moisture data directly into your batching controller or SCADA system on every batch.

The reason coarse aggregates need a specifically engineered probe comes down to two things. Particle size and abrasion.

Standard fine-material probes are designed for sand and granules up to 4mm. Run gravel, crushed stone, granite, or RAP through those conditions and the sensor head wears quickly, accuracy degrades, and you end up replacing the probe entirely. The Seztec SONO Xtrem® is built specifically for coarse, abrasive aggregate environments where standard probes fail.

In concrete batching and asphalt production, the moisture content of coarse aggregates like gravel and crushed stone directly affects your mix water calculation. A 1% variation in aggregate moisture that goes uncorrected changes your effective water-to-cement ratio on every batch. Across a full production day that drift adds up to inconsistent mix quality, wasted cement, and potential non-compliance with mix design specifications.

The Seztec SONO Xtrem® coarse aggregate moisture probe

The Seztec SONO Xtrem® is a fixed online moisture probe engineered for continuous measurement in coarse, abrasive aggregate applications. It handles particle sizes up to 1.25 inches including granite, gravel, crushed stone, and Recycled Asphalt Pavement (RAP), and is built to operate reliably in the harsh conditions those materials create.

It is the heavy-duty variant of the SONO® sensor family from IMKO, distributed and supported in the United States by Seztec USA. Where the SONO VARIO® handles fine sand up to 4mm, the Seztec SONO Xtrem® is specifically engineered for everything coarser and more abrasive.

The Seztec SONO Xtrem® uses the same patented TRIME® TDR measurement technology as the rest of the SONO® sensor family. For a full explanation of how TRIME® TDR works see the SONO VARIO® sand moisture sensor page.

 

 

How the Seztec SONO Xtrem® handles coarse aggregate moisture measurement

Measuring moisture accurately in coarse aggregates presents two problems that fine-material probes cannot solve.

The first is particle size. A piece of gravel or crushed stone sitting against a sensor face occupies the entire measurement contact area. The moisture reading reflects that one particle, not the material flowing past it. For accurate bulk moisture data you need a probe that measures through a representative volume of material, not a surface contact point.

The second is abrasion. Granite, crushed stone, and RAP are highly abrasive. They wear sensor heads continuously in a production environment. A standard probe loses accuracy as the sensing surface degrades and eventually needs replacing entirely.

The Seztec SONO Xtrem® addresses both problems. It uses TDR technology to send an electromagnetic pulse through a significant volume of surrounding material rather than reading the surface. The measurement averages across that volume so individual particle variation and surface anomalies do not skew the result.

The sensor head is engineered from high-grade ceramic specifically for abrasive contact with coarse materials. The probe’s onboard electronics monitor sensor head wear continuously and apply automatic correction to measurement values as wear occurs. Accuracy stays consistent throughout the service life of the head without manual recalibration.

When the ceramic head eventually reaches end of life you replace the head only. The probe body, electronics, and calibration settings remain in place.

What makes the Seztec SONO Xtrem® different from a standard aggregate moisture probe

 

 

Why quarries and asphalt plants use the Seztec SONO Xtrem®

 

 

Coarse aggregate moisture probe applications by industry

 

 

Compatible materials for the Seztec SONO Xtrem® moisture probe

The Seztec SONO Xtrem® starts where the SONO VARIO® fine sand sensor stops. It handles coarse aggregates and abrasive bulk materials from 4mm up to 1.25 inches (32mm) in particle size.

Typical materials include gravel, granite, crushed stone, grit, coarse concrete aggregates, Recycled Asphalt Pavement (RAP), foundry sand, ore, slag, and coal.

For fine sand and granular materials up to 4mm, the SONO VARIO® sand moisture sensor is the correct probe. For full installation options, interface documentation, and delivery scope, download the product manual or contact Seztec USA directly.

Who uses a coarse aggregate moisture probe

Asphalt plant managers who need real-time RAP and coarse aggregate moisture data to control dryer temperature and mix ratios. Quarry operators providing continuous moisture data during crushing and screening and moisture certificates to concrete producers. Concrete batching plant operators working specifically with coarse aggregate fractions who need automatic moisture correction in their batching controller.

If your plant handles coarse aggregates, gravel, crushed stone, or RAP and you are currently relying on periodic manual checks or oven drying, the Seztec SONO Xtrem® is worth evaluating.

Seztec SONO Xtrem® coarse aggregate moisture probe — frequently asked questions

Q: What is the difference between the Seztec SONO Xtrem® and the SONO VARIO® sand moisture sensor? The SONO VARIO® is designed for fine sand and granular materials up to 4mm. The Seztec SONO Xtrem® is engineered for coarse aggregates, gravel, crushed stone, and RAP up to 1.25 inches. The key physical differences are the ceramic abrasion-resistant sensor head, the replaceable head design, and the automatic abrasion correction system. If you are working with fine sand, the SONO VARIO® is the right probe. If you are working with gravel, crushed stone, or RAP, the Seztec SONO Xtrem® is the correct choice.

Q: What is RAP and why does it need a specialized moisture probe? RAP stands for Reclaimed Asphalt Pavement. It is crushed and processed material recovered from existing asphalt roads and used as a recycled component in new asphalt mixes. RAP moisture varies significantly depending on weather, stockpile conditions, and processing time. It is also highly abrasive. The Seztec SONO Xtrem® handles both the particle size and abrasion demands of RAP measurement and provides continuous online moisture data to control dryer temperature and mix ratios in real time.

Q: How does the Seztec SONO Xtrem® connect to my plant control system? The probe supports 0–20mA analog output and RS485, IMP-Bus, and Profibus digital interfaces. For plants with multiple aggregate silos, several Seztec SONO Xtrem® probes can be networked in a bus configuration on a single batching controller or SCADA system. This is particularly useful for asphalt plants measuring both virgin aggregate and RAP moisture simultaneously on separate feed conveyors. For full interface documentation see the product manual or contact Seztec USA.

Q: Can I run the Seztec SONO Xtrem® alongside the SONO VARIO® on the same plant? Yes. Many concrete batching plants run both probes simultaneously — the SONO VARIO® measuring fine sand moisture and the Seztec SONO Xtrem® measuring coarse aggregate moisture. Both integrate into the same SCADA or batching controller giving your system complete moisture data across all aggregate fractions for full w/c ratio control on every batch.

Q: What is the built-in temperature compensation and why does it matter for coarse aggregates? A temperature sensor sits millimeters below the ceramic sensing head. It provides real-time material temperature data and applies automatic compensation to the moisture reading. Coarse aggregates vary significantly in temperature depending on season, weather, and storage. Without built-in compensation those temperature changes introduce drift into moisture readings over time. Built-in compensation keeps the reading accurate regardless of material temperature variation.

Q: Is this the same sensor as the IMKO SONO VARIO Xtrem? Yes. The Seztec SONO Xtrem® is the IMKO SONO VARIO Xtrem® probe rebranded and supported for the US market by Seztec USA. Seztec USA is the authorized US distributor for IMKO moisture measurement products and provides full US-based sales, application engineering, and lifetime support.

 

 

› Highly abrasion-resistant
› Precise measurement even under extreme conditions
› Reliability even with steam or varying sizes of sand and gravel
› Simple installation in containers, shafts, silos and at conveyor belts
› Automatic correction of measuring value in case of abrasion of the probe head without re-calibration
› Floating averaging, adjustable filter and up to 15 calibration curves
› A RS485 interface for SCADA integration
› A data bus protocol to connect several SONO probes
› Various communication options like Profibus, Ethernet and more

Manual SONO-VARIO Standard and Xtrem_Seztec USA

Imko Display SONO-VIEW – Seztec USA