Reconstruction of a Section of the A9 Motorway Using Recycled Aggregate Concrete

Paper by ZACHLEHNER ULLMANN from ISCR 7th 1994 Vienna Austria

In Germany the use of concrete with aggregates obtained from crushed concrete (RC aggregate) has been quite limited in comparison to other countries such as the USA and Austria. This situation is caused mainly by the lack of appropriate regulations for this kind of application. For this reason, the award to Heilit + Woerner of the reconstruction of the A9 motorway section between Dessau and Zarbig using RC aggregate concrete was only possible because it was proposed in form of an alternate contractors option. The method proposed to place the pavement in two layers and was based on the experience gained from the reconstruction of the Al motorway in Austria and on the airport of Prague. Experiences gained from this project indicate that the content of RC sand in the new concrete should be limited because of its negative effects on the workability and for economic reasons more than because of its supposed negative effect on the flexural strength and/or the frost resistance.

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