Use of recycled aggregates in fibre reinforced shotcrete: mix design, properties of fresh concrete, and on-site documentation

摘要

A demonstration project using up to 20% recycled aggregates in fibre-reinforced shotcrete started in the summer of 1999 in Oslo. The project was a full-scale laboratory and on-site test of shotcrete containing recycled aggregate, used to stabilize a permanent lightweight bridge construction. On-site documentation showed that shotcrete with recycled aggregate exhibited excellent spraying and compacting properties, and adheres to the substrate very well, compared to a reference mix. No spraying difficulties occurred due to the use of recycled aggregates and the need for accelerator decreased for all shotcrete-mixes with recycled aggregates. The compressive strength of shotcrete with recycled aggregate was reduced compared to a reference mix without recycled aggregates, but the strength obtained still exceeded 45 MPa at 28 days.