Spain studying rubber crumb in road surfaces

ERJ staff report (DS)

Solihull, UK -- Spanish researchers have shown that it is possible to use post-consumer rubber granulate in road surfaces. Not only that, but it is a practical possibility and economically viable.

Jesus Maria Nunez Imaz, Director-General of the Spanish tyre collection agency, Signus, told delegates to the annual meeting of the UK's Tyre Recovery Association that the Spanish government has a policy to substantially expand the use of rubber granulate in asphalt.

Currently some 3 percent of all tyre arisings in Spain end up in rubber asphalt, but the government has set a target to increase this to a huge 45 percent of all arisings by 2015.

Imaz said that, given the mid-term public spending cuts in Spain, this figure could be seen as unrealistic, but that there is a strong intent to increase the amount of rubber used in road surfaces and he expected that figure of three percent to increase to ten percent or more over the next few years. Once public spending increases once more, he suggested that the 45 percent figure is not unrealistic.

Imaz said road suppliers in Spain are very positive towards the technology and have shown that it is practicable and economically viable to use rubber crumb in road surfaces.

Many people have believed that as rubber crumb is added to asphalt, it makes the material too viscous to process economically. However, said Imaz, this is not necessarily the case.

Modified asphalt currently uses large volumes of SBS styrenic co-polymers. As these polymers are mixed with the asphalt, they melt, and so do not adversely affect processing of the asphalt. These virgin polymers have recently risen substantially in price and are becoming scarece, as the availability of butadiene monomer has become an issue.