Use of recycled materials in constructions

There are several options for the use of recycled materials in constructions. For every option a number of technical and environmental aspects are relevant. This paper describes several models which can be used to take the optimal decision. In general the world-wide used Life Cycle Assessment can be used as a multi-parameter model for the environmental effects. A new single indicator model, the Eco-costs/Value ratio simplifies the decision process. For waste management the model called Delft Ladder is developed. The approach called Design for Recycling can be used to optimize design or constructions for later reuse. In the same way, the Design for Disassembly can be used for demolition. For the technical aspects two models were developed concerning degradation processes and high-graded applications.