More sustainable asphalt made from recycled tires and organic wax

Ana María Rodríguez Alloza, a researcher from Universidad Politécnica de Madrid (UPM), developed a new type of asphalt that could be considered more ecological, using rubber powder from recycled tires and organic waxes.

To make asphalt, additives and bitumen are warmed to a certain temperature at which the mix is mouldable for placing. A study by UPM has shown that it is feasible to reduce the manufacturing temperature and the placing of asphalt mixtures with up to 30 degrees, while maintaining good mechanical behaviour. Reducing the necessary temperature also reduces energy and greenhouse emissions.

The new asphalt includes rubber powder from old tires. While tires are recyclable, its production exceeds 300,000 tons a year, so using it in asphalt would reduce waste. In addition, by using rubber powder, the amount of bitumen could be reduced.

In addition to recycled rubber, the new asphalt also includes a series of organic waxes. When reaching their melting point, these waxes reduce the binder viscosity of the mixture, thus reducing the manufacturing temperature.

According to Rodríguez Alloza, the new asphalt would be especially suitable for warm weather countries such as Spain.