The building explosion during the years 1945-1960 will inevitably lead to increased demolition in the next decades since the lifetime distribution of structures no longer fulfills its functional social requirements in an acceptable way. In the building period mentioned there was a great increase in reinforced and prestressed concrete construction. Consequently there is now more and more concrete to be demolished. Increasingly severe demands will be made upon demolition technology, including the demand for human- and environment-friendly techniques. On the other hand, the possibility of disposing of debris by dumping is steadily diminishing, especially close to major cities and generally in countries with a high population density. At the same time in such countries and in such urban areas a shortage of aggregates for making concrete will develop as a result of restrictions on aggregate working because of its effect on the environment and because of the unavailability of aggregate deposits due to urban development. From the foregoing it follows that recycling and re-use of environment- and human-friendly demolished and fragmented building rubble should be considered. The translation of this general problem into terms of materials science is possible by forming clear ideas of adhesion and cohesion: the whole process of demolition, fragmentation, and recycling or re-use of concrete is to break the bonding forces between atoms and molecules and to form new bonds across the interfaces of various particles of either the same nature or a different nature.

Inhalt
1 Organization.- 1 Introduction.- 2 Program.- 3 Participants.- 4 Proceedings.- 2 Lectures, Discussions, and General Discussion.- 1.1 Introduction and stating the problems.- 1.2 Additional information given during the presentation: Case study of the Netherlands.- 2.1 The structure of concrete: a macroscopic view.- 2.2 Discussion.- 3.1 Principles of adhesion bonding in cement and concrete.- 3.2 Discussion.- 4.1 Contamination problems in the recycling of concrete.- 4.2 Discussion.- 5.1 Fracture energy of concrete.- 5.2 Discussion.- 6.1 Adsorption sensitive fracture and fragmentation.- 6.2 Discussion.- 7.1 Economics of concrete recycling in the United States.- 7.2 Discussion.- 8. General Discussion.- 3 Introductory Lectures to Workshops, Minutes of Workshops, Workshop Reports, and Contributions to Workshops.- 1. Workshop 1 Fragmentation of plain and reinforced concrete.- 1.1 Minutes of workshop 1.- 1.2 Contributions.- 1.2.1 Demolition techniques for concrete structures.- 1.2.2 Observed energy dissipative features of crack propagation in mortar.- 2. Workshop 4 Fragmentation of prestressed concrete.- 2.1 Introductory lecture: Demolition of prestressed concrete structures.- 2.2 Minutes of workshop 4.- 2.3 Contributions.- 2.3.1 Explosives for localized cutting in concrete.- 3. Workshop 5 Contamination effects on fragmentation, fibre and polymer concrete.- 3.1 Introductory lecture: Materials characterization for fragmentation.- 3.2 Report on workshop 5.- 3.3 Contributions.- 3.3.1 Correlation between fracture toughness and zeta potential of cementstone.- 4. Workshop 8 Fragmentation of all types of concrete research needs.- 4.1 Minutes of workshop 8.- 4.2 Contributions.- 4.2.1 Recommended flow chart for future research activities concerning demolitionand fragmentation of concrete.- 5. Workshop 2 Recycling of concrete (aggregates for use in concrete).- 5.1 Introductory lecture: Crushed concrete as concrete aggregate.- 5.2.1 Minutes of workshop 2.- 5.2.2 Report on workshop 2.- 5.3 Contributions.- 5.3.1 Classification of recycled aggregate, proposed in the Netherlands.- 5.3.2 Fragmentation and recycling of reinforced concrete, some research results.- 5.3.3 The role of a polymeric interlayer in improving mechanical characteristics of recycled concrete.- 6. Workshop 3 Re-use of concrete (other than as aggregate).- 6.1 Introductory lecture: Recycling of concrete into new applications.- 6.2.1 Minutes of the presentation of the introductory lecture.- 6.2.2 Report on workshop 3.- 6.3 Contributions.- 6.3.1 Example of re-use of concrete in France.- 6.3.2 Reflecting properties of a road surface.- 7. Workshop 7 Contamination effects on recycling and re-use.- 7.1 Introductory comments.- 7.2.1 Minutes of workshop 7.- 7.2.2 Report on workshop 7.- 7.3 Contributions.- 7.3.1 The effect of gypsum on length change and strength of portland- and portland blastfurnace cementstone specimen.- 7.3.2 The influence of contaminants on the quality and the behaviour of recycled concrete.- 8. Workshop 8 Future demolition-friendly materials.- 8.1 Introductory comments.- 8.2 Minutes of workshop 6.- 8.3 Contributions.- 8.3.1 Some notes regarding the performance of waste materials and concrete in building components.- 4 Concluding Remarks.- Concluding remarks.- List of Participants.