Abstract Manager

Asphalt road construction is one of the industries in which almost all asphalt produced is already being reused or recycled. Unfortunately, there are always layers of tar or coal tar from old construction projects that cannot be recycled. Material containing tar often must be disposed of at high cost. In addition, a huge amount of landfill space is required for storage. In order to achieve the high reuse and recycling rates, considerable effort is required in the extraction process and in processing. For example, the asphalt must be milled, transported and stored in as many layers as possible to be able to reuse it in as pure a form as possible. This involves a great deal of logistical effort and high costs. This is because sufficient (covered) storage space must be provided at the asphalt mixing plant for so-called stockpile management, but this is not usually available.

To minimize the costs of tar disposal in the future and to enable the recycling of the stones from the tar granulate, an alternative method of processing the tar granulate has been searched for. Several years of development have shown that it can be a suitable way to process the extracted material in such a way that the road tar and the stones are separated as gently and environmentally friendly as possible so that they can then be reused in a controlled manner. Separation by means of chemical solvents or the use of extreme cold is therefore out of the question. Instead, the idea of separating the tar granulate into the components rock, tar and mastic using only water has been pursued. In a long series of tests, a prototype of a purification plant has been developed and tested, which now makes it possible to achieve the above-mentioned separation goals. The process was implemented on an industrial scale in 2025 and has successfully passed the test phase.

In the summer of 2026, the first construction project is to be implemented, in which material obtained from the AB site will be treated using this process and then directly reused on site.

Overall, this can make a significant contribution to even greater environmental protection and resource conservation in asphalt road construction. In the future, this new process will significantly reduce the disposal costs for PAH removal and the volume of tar-containing road construction waste, as well as expand the recycling options in bitumen-bound road construction.