In order to recycle waste concrete produced from superannuated concrete structures such as reinforced concrete buildings, highway and underground structures, stone crushers and classifiers are used to crush or classify the waste concrete so that they can be re-used as the aggregate for concrete or the base for roads.

[Construction of the equipment]

Since the waste concrete are produced from the sites in urban area waste concrete disposal equipment are often installed in the suburbs of cities, and such equipment are required not to cause trouble to the regional residents.

In setting up the plan for the waste concrete disposal equipment, Kobe Steel designs the equipment so as to reduce dust and noise and provides suitable measures to prevent environmental pollution.

Kobe Steel also forecasts the extent of environmental pollution affecting the vicinity, retains and utilizes the noise prediction system and dust prediction system to provide preliminary measures in advance.

The Photo. 1 shows the example of the results of prediction.

Photo. 1
Examples of prediction study

<Before prediction>

<After prediction>

Since the site for installation of the waste concrete disposal equipment is restricted, a jaw crusher is used for the primary crushing process and an impact crusher for the secondary crushing process as the standard practice.
A typical disposal flow of waste concrete is shown in Fig. 1.

Fig.1

[Features of special equipments for waste materials]

Special jaw crusher for waste concrete:

Unlike stones, since the strength of waste concrete is low and relatively uniform, crushing is easy and the machine can be designed with reduced weight.
Kobe Steel's "KEEPJAW" which is the special machine for waste materials employs the saw tooth type jaw plate to increase the crushing ratio of the setting at the outlet and to cause the crushing force to work by the shear force, so that the machine can easily crush asphalt even in summer. (Refer to Photo. 2.)

Photo.2

Impact crusher for waste materials:

Reinforced bars are mixed in the waste materials, therefore, an impact crusher is used to crush the waste materials by Impact plate.
Impact plate of the impact crusher is supported by springs to provide a relief mechanism so as to prevent damage to the body even if large materials which cannot be crushed are mixed. (Refer to Photo 3.)

Photo.3

Mobile crusher:

In order to dispose the waste concrete at the construction site and utilize them at the site, the crusher equipped with traveling unit obtains high evaluation in recent years and is generally used for such applications.(Refer to Photo 4.)

Photo. 4