Crush + Size Technology has developed special core competencies in the development of efficient crushing processes based on rotating rollers.

The process, which is advantageous in many applications, also shows its advantages especially in asphalt recycling. Because here it is of particular importance for the quality of the recycling material if the supporting grain – i.e. the aggregate for the primary asphalt production – is separated from the bond with the bitumen binder in such a way that it can be used again in the next asphalt mixing process with virtually no loss of quality.

To achieve such a result, a primary crusher in the primary crushing stage crushes the removed asphalt to a grain size of <80 mm. The machine type described here is the Asphalt Crusher (ACR), specifically designed for the handling and gentle crushing of removed asphalt. To handle bulky clumps and large edge lengths, the crushing tool has been designed to ensure direct feed of the material through large ripping teeth. The teeth engage the material slowly with low circumferential speed, resulting in gentle and low-wear pre-crushing in the first stage. Clumps and plates with edge lengths of up to 1.2 m and thicknesses of up to 400 mm are processed.

Fractions below the defined target grain size are sorted out before reaching the crusher via a roller grizzly. This concept allows for throughput of up to 400 t/h, with the proportion of large clumps in the feed material reaching up to 50%. The gentle crushing of the removed asphalt by the ACR Asphalt Crusher results in a final grain size with minimal increase in fine and sand fractions.

The layered construction of asphalt roads requires different grain compositions. Recycled asphalt is reintroduced into the mixture for reuse.

The particular challenge in asphalt crushing is producing smaller grains. When processed using dynamic impact crushing, this results in high proportions of sand or fine fractions.

For gentle crushing of asphalt granulate with a grain size of 0-80 mm, the SGC technology is excellent. Grains ranging from <8 to <22 mm can be produced in one process. Using the principle of compression crushing, the matrix grains are shifted against each other, causing the asphalt to disintegrate into individual components. The increase in fine fractions is extremely low.

If the asphalt has a larger grain structure and a smaller grain size is desired, the SGC Sand and Gravel Crusher also functions as a splitter to produce this desirable grain shape.

The extremely valuable grains of 5-8 mm are produced to a much greater extent than is possible with impact crushing.

Both crushers have a hydraulic overload protection in order to automatically remove disturbing material from the crushing space without damage of the machine. In order to immediately react upon changing material characteristics in the feed material, also the crushing gap in both crushing steps can individually be adjusted by means of the control panel during the crushing process. The application of a subsequent sieving unit is possible for example in order to lead back oversized grain to the secondary crusher.

Depending on the needs of the operator, the roll crushing unit can be either a track mobile or a wheeled mobile crushing unit. The crushers can also serve as individual modules in stationary asphalt processing or recycling plants.

Depending on the machine size the crushers achieve performances of up to 300 t/h. In order to ensure an efficient operation of the unit, the control system takes over the optimum feed. In the knowledge around the user demands regarding the availability, all Crush & Sizes machines can be equipped with a quick-change system with which the rolls can be exchanged in no time.