Nothing lasts forever, even bricks, steel and concrete. The trouble with this rubble is that it can't be compacted, and it doesn't decompose. And up till now its been dumped as landfill. In fact it makes up 40 per cent of all landfill.

Some concrete can be recycled, but its re-use is limited. This is because of the difficulty in separating the stones, known as aggregate, from the reinforcement steel and cement. But Kwesi Sagoe-Crentsil from the Australian science agency, CSIRO, may have the answers.

"Because of the difference in properties, we have to check the quality, we have to look at all the foreign material that would be introduced in the recycling operation, to see how that would affect the performance of the concrete."

After the concrete is crushed, it is remixed with chemical additives and set in a controlled environment. This is new concrete and this is recycled concrete. The pale clumps amongst the recycled stones are pieces of the old cement which can weaken the recycled concrete. So core samples are taken and rigorously tested in the lab and in the field. This bike path is made from recycled concrete. It is regularly checked by CSIRO and, so far, is showing no signs of strain.

"At this stage of our work, we are looking at only non structural types of applications, but as we work we are still carrying out some tests so in the near future, we will see how the possibilities of using it for structural types of applications."

It means that while some buildings are no longer of any use, the materials they're made from can be given new life.

Long Version of Recycled Concrete.

Kwesi Sagoe-Crentsi
CSIRO Manufacturing and Infrastructure Technology
PO Box 56
Highett VIC 3190

Kwesi.Sagoe-Crentsil@csiro.au