The US-based National Centre for Asphalt Technology (NCAT) has released a study that says the use of ground tyre rubber powder in asphalt mixture improves the performance, thus paving the way for the use of sustainable material in road construction.
NCAT says that by increasing the use of ground tyre rubber, asphalt producers will benefit from price stability as compared to more volatile oil prices, which impact the cost of traditional, oil-based polymers. Furthermore, the study indicates that the asphalt manufacturing process, whether cryogenic or ambient, does not impact the performance of the rubber material or, ultimately, the asphalt.
Benefits of using ground tyre rubber (GTR), according to the US Environmental Protection Agency, include:
longer lasting road surfaces, reduced road maintenance, cost effectiveness, lower road noise and shorter braking distances.
The NCAT study addressed these needs and indicates that surface area and particle size of the rubbers had the most influence on the modified asphalt binder – smaller particle size, which equates to larger surface area, provides better performance. Based on the study results, researchers also recommend that 10% of GTR is an appropriate level of loading for asphalt binders. (RJA)