Bomag, a Fayat Group brand, has launched the "Binder-Cast" intelligent binder injection system for its RS 460 Recycler and Soil Stabilizer, targeting full-depth reclamation (FDR) of aged asphalt pavements and in-situ soil stabilization on rural highway rehabilitation projects. In FDR operations, cement, lime, or foamed bitumen is injected into the reclaimed material as the milling drum pulverizes the pavement. The treatment rate-typically 3 to 7 percent by weight of the reclaimed material-must be calculated based on the actual mass of material being cut per unit time. Traditional recyclers operate on a fixed injection rate based on assumed cutting depth and material density. When the actual material is denser or wetter than assumed, the treatment rate becomes too low, producing a weak stabilized layer; when the material is lighter or drier, the over-application of binder wastes material and produces a brittle, crack-prone base.
The Binder-Cast system integrates a "Microwave-Based Material Moisture Sensor" mounted inside the recycler's mixing chamber and a "Cutting-Depth-Linked Displacement Encoder" on the rotor depth cylinders. The engineering breakthrough is the "Real-Time Mass-Flow Calculation." The microwave sensor measures the moisture content of the reclaimed material within the mixing chamber at 20 hertz. The depth encoder measures the instantaneous cutting depth. From these two inputs, combined with the machine's forward speed (measured by a radar speed sensor), the ECU calculates the actual dry mass of material passing through the mixing chamber per second.
The ECU then modulates the "Binder Metering Pump" speed in real-time, ensuring the injected binder weight matches the calculated material mass at the exact specified treatment percentage. For foamed bitumen injection, the system additionally modulates the "Hot Water Injection Rate" into the expansion chamber to maintain the optimal foaming expansion ratio (typically 10 to 15 times) as bitumen flow varies. The system logs the actual applied binder rate, cutting depth, forward speed, and moisture content for each 1-meter longitudinal increment of the stabilized layer, providing a complete as-built record for quality assurance. This automated mass-flow control reduces binder consumption by 8 percent on average while increasing the uniformity of the treated layer, dramatically reducing the need for post-construction coring verification.
