Extremely hot or cold periods are a serious problem to road surfaces: many cracks, potholes and car ruts are the consequence. It’s expensive to repair them and the construction sites cause thousands of traffic jams every year and thus lead to an increase in unnecessary car emissions.
The new pavement was developed by Prof Pilakoutas within the European research project ECOLANES. It is based on roller-compacted concrete (RCC), a mixture which uses hardly any water. The moment it is compressed the concrete is firm and immediately ready for light traffic. This shortens the time of road constructions considerably.
The new concrete is reinforced with steel fibres which makes the material tougher and extends the lifespan of the pavement. In order to make this new concrete an ecological product, the researchers have selected steel fibres that are leftovers from the recycling process of waste tyres.
Every year more than 3.2 million tons of waste tyres are recycled in the European Union, but so far there was little use for the metal wires which are part of reinforcement of the tyres. For the new concrete the recycled steel fibres are ideal. The steel fibres are at least 50 per cent cheaper compared to steel fibres from a metal processing plant. There is no need for raw material to be mined which saves additional energy and resources.
The energy balance of the new material has been the focus of the researchers and one aim was to make the concrete recyclable itself. If the pavement gets damaged it can be removed, crushed and reused. This reduces once more the use of raw materials and transportation costs.
To make sure that the new material withstands both the forces of nature and intensive traffic, the concrete has been tested in many ways. For example, in the lab the concrete was exposed in a climate chamber to extreme temperatures. The mix has also been paved on different test sites in England, Cyprus, Romania and Turkey to examine the material under different climatic conditions and traffic situations. The results have been promising and the scientists are now looking for an industry partner to market, mass-produce and deploy the new eco-concrete on a larger scale.
(6 September 2010)
Corinna Luecke