What Is a Fiber Additive Unit?
A fiber additive unit is the dosing equipment that weighs cellulose-based or mineral fiber precisely and feeds it into the mixer when an asphalt plant produces stone mastic asphalt (SMA) and similar special mixes. Fiber keeps the binder from draining off the aggregate in bitumen-rich mixes; the mix therefore stays homogeneous during haulage and paving, and the pavement resists rutting and cracking better.
This quality, which is expected on motorways, airports and heavily trafficked city roads, depends on adding the right amount of fiber at the right moment in every batch. Alfamix Asfalt integrates this equipment into new plants, above all the batch type stationary asphalt plant, and also designs it so that it can be retrofitted to existing plants.
Which Mixes Is It Used For?
Fiber is most widely used in stone mastic asphalt (SMA) production. It is also preferred in mixes with a thick bitumen film, such as porous asphalt and thin wearing courses. Pelletised (granular) and loose fibers are selected according to the mix design.
Main Features and Working Principle
Main Features
- Fiber storage hopper: Lidded body that stores pelletised or loose fiber and can be filled from big bags or sacks.
- Precise weighing: A weigh hopper on load cells weighs the recipe quantity separately for every batch.
- Screw feeding: Transfers material from the storage hopper to the weigh hopper in a controlled way.
- Pneumatic conveying: The blower and conveying line carry the fiber into the mixer quickly and without loss.
- Automation integration: Recipe selection, dosing monitoring and reporting are handled from the plant control screen.
- Robust body: Steel construction suited to site conditions, with easily accessible maintenance points.
Working Principle
The fiber additive unit works in step with the production cycle of the plant:
- The operator selects a recipe containing fiber on the automation screen.
- The screw conveyor transfers fiber from the storage hopper to the weigh hopper; feeding stops when the target weight is reached.
- When the hot aggregate is discharged into the mixer unit, the weighed fiber is blown into the mixer through the conveying line by the blower.
- The fiber disperses among the aggregate during the dry mixing stage; bitumen and filler are then added and mixing is completed.
- The system starts weighing again for the next batch.
The fiber content is set by the mix design; in SMA mixes it is generally around 0.3–0.5% of the mix weight. Because manual feeding of such small quantities is prone to error, automatic dosing that works together with the asphalt plant weighing system is preferred.
Advantages of the Fiber Additive Unit
- Consistent mix quality: Every batch receives the same amount of fiber; the risk of binder drain-down and segregation is reduced.
- Occupational safety and labour savings: There is no need to carry sacks to the mixer platform and add them by hand.
- Material savings: Precise weighing prevents overuse of fiber, which is a costly additive.
- Records and traceability: Fiber consumption is recorded batch by batch, which makes specification and supervision reporting easier.
- Production speed: Dosing is done without lengthening the cycle time, so plant capacity is maintained.
- Flexibility: Quick changeover between different fiber types and recipes.
An Affordable and Durable Fiber Additive Unit from Alfamix Asfalt
Experienced Team, High-Quality and Durable Equipment
Alfamix Asfalt designs and manufactures the fiber additive unit at its own production facility in Ankara. Our founders’ 50 years of industry experience come together with an engineering and manufacturing team that knows every unit of an asphalt plant from the field. Manufacturing in-house removes intermediary costs, which allows us to offer quality equipment at affordable prices.
Our units are built with quality steel and with motors, gearboxes and weighing components from reliable brands. Our aim is to produce durable, easy-to-maintain equipment that runs trouble-free for years at the pace of the busy season. Installation, commissioning, integration with asphalt plant automation systems and after-sales spare parts support are also provided by our team.
Request an Affordable Quote
For a fiber additive unit suited to your plant capacity and the mix you will produce, fill in our quotation form or give us a call. You can watch the plants and equipment we manufacture at work on the Alfamix Asfalt YouTube channel.