Recycling of construction and demolition waste - Status and new utilisation methods

Anette Mueller, Bauhaus-University Weimar, Germany

Sustainable development means for the building materials sector among other things the systematic realization of material recycling. The immediate target is the reduction of the volume of construction and demolition waste (CDW) occurring, and at the same time preserving resources that are becoming more and more scarce. In this way, used building materials become source materials for new products. This calls for new approaches and knowledge.

The focus of research in the beginning of the "recycling age" was the reuse of concrete. The technologies for the processing are adopted mainly from the extractive industry. In the paper specific developments for the recycling of CDW which aim at the improvement of the quality of the produced aggregates are discussed. The impacts of recycled concrete aggregates on the quality of concrete were presented in detail. On basis of this knowledge different standards or recommendations for the reuse of recycled concrete aggregates in concrete were developed in Europe. These standards are the prerequisite to promote the reuse of recycled concrete aggregates in practice.

Compared with concrete rubble the utilisation of masonry rubble poses the larger challenge. The properties of masonry rubble prepared as recycling construction materials, which are important for their utilisation, are discussed on the basis of own measurement and results from the literature. Different variants of utilisation described in the literature are introduced. The so called product recycling i.e. the re-use and further use of the material in its original form plays a small, but evident part in the case of old tiles and bricks. More important is the material recycling i.e. the utilization after processing. Fields of applications are wide spread - from unbonded systems like filling works, unbonded traffic areas and paths, dam construction, ground improvement, landscape gardening etc. to cement bonded systems, which are increasingly in the focus of research projects.  At the end of the paper the utilization of masonry rubble as raw material for lightweight aggregates is described.


Keywords: Recycling, Construction, Processing