ABSTRACT
The lifetime of buildings depends on their flexibility to be reused and, more and more, on economic questions as the annual costs for energy. Beside, most of the towns in dense populated environment do not grow anymore to their outskirts, but are redeveloped on their existing area. Consequently buildings of the last decades are replaced by modern buildings with sustainable and architectural appealing design. Hereby the deconstruction and the management of construction and demolition waste of the existing buildings is a key issue in the development of sustainable construction. Prevention, re-use and recycling are the basic approaches to waste management. This contribution introduces waste management in reference to demolition techniques. In particular different demolition methods are presented for the main structural typologies and materials. Also the factors relevant to the choice of the demolition technique and its influence on the eventual recovery of materials are investigated. Recycling is not only a question of the total costs of a deconstruction, but also depends on the fractions of the materials, which do not all permit recycling. Besides, options for the future are discussed. Typical buildings at their end-of-lifetime today were not constructed in the past with any thoughts on possibilities of later reuse of materials or structures. But even today, the deconstruction as one possible strategy at the end-of-lifetime is not deeply investigated. Thus, this paper focuses as well on the question, whether we can reach zero-waste deconstruction techniques in the near future or not. But even if we could, what additional possibilities exist today for concrete-gravel or other recycling products? Especially in high populated areas of Europe the amount of recycled concrete or masonry coming from deconstruction projects is about twice as much as the need for recycled material e.g. as an alternative to natural gravel.
