Processing concrete rubble from road construction projects is usually carried out using an impact crusher. The feed material typically has a size range of 0/800 mm. Larger pieces are reduced using an excavator equipped with a crusher attachment.
These machines are normally fitted with an independent double-deck pre-screen with side conveyor, specifically designed to separate the 0/15 mm fraction, also known as screening sand. The blow bars, mounted on the rotor, rotate at a speed of about 600 rpm. They throw the feed material against the impact aprons, reducing the material by the impact. A post-screen on the crusher’s output conveyor screens the crushed concrete rubble to size, with oversize material being returned via a recirculation conveyor. Producing a 0/40 mm finished product typically results in a capacity of between 150 and 200 tons/hour.
Cone crushers
Producing aggregates with a cone crusher
To produce concrete aggregates for reuse in mixing plants and generate maximum value, it is essential to screen them accurately into three fractions: 0/6 mm, 6/14 mm and 14/22 mm. The latter two fractions represent the highest value, being approximately three times more valuable than sand.
For reducing or crushing concrete rubble, the impact crusher, as described here, is definitely the most effective choice. Clean and unreinforced concrete rubble, from road construction or demolition projects, often has significant value. The crushing process of the impact crusher is known for producing a high percentage of crushed sand. This results directly from the kinetic energy absorbed by velocity, followed by the explosion of the debris onto the adjustable impact bars.
To create maximum value for reuse in the mixing plants, the objective is clear. Extract as much granulate 6/22mm as possible instead of sand.
To achieve this, the combination of the jaw crusher and cone crusher is the ideal solution.
The forced crushing principle of these machines produces at least 25% more aggregate for the same job compared to the impact principle of an impact crusher.
With the jaw crusher, the concrete rubble is pre-crushed to 0/120mm and fed through to the cone crusher. With the CSS set to 17mm, 0/35 mm is produced in a single pass. The capacity in this setup is between 160 and 180 tons/hour. After screening into three fractions, the result is:
65% of 8/22mm fraction, 20% of 0/8mm fraction and in these settings an overgrain 22/35mm percentage 15%.
