Wet Mix Macadam (WMM) is a comparatively newer concept used for laying the base course, which is placed right before the hot mix asphalt during road construction. The binding materials used for the base in case of WMM are prepared in the plant and then brought to the site for overlaying and rolling. A standard WMM plant comes with the following elements:
· Cold Aggregate Feeders
· Vibrating screen
· Conveyor with load cell
· Pug mill mixer
· Load out conveyor
· Silo or Hopper
· Water tank
· Control Panel inside the cabin
The WMM plant offers the flexibility to supply it with additional cement. The plant is provided with cement hopper and cement silo for pumping the additional cement directly into the pug mill. The motor that comes equipped with screw conveyor of the cement hopper/silo is synchronized with the load cell and the required quantity of cement can be additional to the pug mill.
- Aggregate feeders: The four-bin aggregate feeder of the WMM plant is built to store four types of aggregates. Each of the bins is provided with a gate for manual adjustment and each bin is provided with belts that are pushed by variable speed motors to release the materials to gathering conveyor.
- Single Deck Vibrating Screen: The gathering conveyor belt passes by the vibrating screen before delivering the aggregates to the charging conveyor belt. The vibrating screen filters the over-sized aggregates.
- Charging Conveyor: Once the aggregates are filtered with the help of the vibrating screens, the charging conveyor delivers the aggregates to the pug mill mixer after the load cell attached to the conveyor weighs the aggregates. It sends the material to the panel so that the water and the cement flow can be synchronized.
- The tough structure of the pug mill consists of liner plates, arms, and tips. These are replaceable elements of the WMM plant, which are expected to be changed for better performance. The mixing unit consists of two arms that are similar to each other and are equipped with tips. The material inside the pug mill is mixed well with the help of these arms and tips as it gets sprayed when it comes in contact with water from the pipelines above.
- The cement silo that comes in various capacities, adds the cement directly into the pug mill mixer. Cement is the material that is used as a binding agent, is usually additional in limited quantities with the help of the screw conveyor with variable speed motor.
- Control panel: The control panel placed inside the cabin, which is usually located to have a complete view of the plant, provides total control of the machine with the help of a user-friendly software.
- The load out conveyor is the one which transfers the combination to the storage silo which in turn pumps the material into the trucks.