São Paulo – The movement for a more sustainable world has reached Brazilian highways. Over the last seven years, 2,200 kilometres of roads have been resurfaced in the country using ecological tarmac, made from recycled tyres. The extension represents just 2.43% of the tarmacked highway grid, but the disposition of road operators, who are using the product on new stretches, shows that the initiative may progress further. The benefit for the globe? Less old rubber disposed of and less work for nature, which takes around 150 years to decompose a tyre.
Of all highways in the country recovered with ecological tarmac, 443 kilometres were concluded last year, according to figures disclosed by the Brazilian Association of Highway Concessionaires (ABCR). In 2010, the total was 340 kilometres and, in the previous year, 290 kilometres received green tarmac. And this way, little by little, rubber is taking over the roads.
"We are eliminating the disposal of between 450,000 and 500,000 tyres into nature,” said the works coordinator at CCR AutoBAn, Gustavo Anfra, regarding the projects that the company has been developing in highways under concession.
CCR Autoban completed the resurfacing of 180 kilometres of rubber tarmac on Bandeirantes highway. The organisation also used the product in 200 kilometres of Anhanguera highway and is working on another 94 kilometres of the same road. Both highways connect the city of São Paulo to the interior of the state.
According to Anfra, the company decided to use the rubber tarmac due to environmental matters. The product, however, also has better performance than traditional tarmac. The sound of friction with tyres is lower, the volume of spray from the vehicle ahead is too and the layer applied may be thinner, as the quality of the mixture is better.
But, most of all, ecological tarmac lasts longer. "The lifespan is 30% greater than that of conventional tarmac. The conventional product lasts from five to six years and this lasts from eight to ten,” says Anfra. According to the works coordinator at CCR AutoBan, as the tarmac with rubber is more resistant, fewer interventions are necessary and that results in less hardships on the road. On the other hand, ecological tarmac is around 40% more expensive. "It is a little more expensive, but it is worth the investment when considering the environment,” he said, adding up the totals of costs and benefits, like durability, etc.
EcoRodovias group has been investing in rubber tarmac since 2002. According to figures disclosed by the company, the product is already in use in 1,000 kilometres operated by five of its controlled companies, which represents 20% of stretches under concession. The use began in the Anchieta-Imigrantes System, in tests, and after the efficiency was proven, the concession holder decided to use it in a broad scale. Anchieta and Imigrantes highways connect the city of São Paulo to the coast.
"Rubber tarmac is around 40% more resistant that the conventional product due to the addition of tyre rubber to the asphalt mass,” said the company, on explaining the reasons to decide on using the new technology.
EcoRodovias also mentions, among the reasons chosen for use, the lower sound level and better grip, reducing the chance of skids, and lower spray, as well as the preservation of the environment. According to the company, in the covering of one kilometre, approximately 600 tyres are reused. "When considering use in the Anchieta-Imigrantes System alone, since it started being used in large scale, the rubber tarmac has already been responsible for the reuse of 360,000 tyres,” informed the company.
But EcoRodovias wants more. It is testing a new product called Warm Mixture at its own mill in the area. Without giving many details, the company stated that the technique, which also uses tyres, reduces fuel consumption at the mill and, mainly, the emission of carbon dioxide into the environment.
In 2005, EcoRodovias inaugurated a mill for production of rubber tarmac. The enterprise has a capacity for 140 tonnes an hour and operates with the support of a laboratory to guarantee the quality and working life of the product. But the EcoRodovias initiative, of making its own tarmac is not that common, as many of the concession holders buy the rubber tarmac from suppliers like Petrobras Distribuidora and Grecca Asfaltos.
What is it?
Ecological tarmac is no more than the mixture of Asphalt Cement to the rubber powder made from crushed tyres, according to the Asphalt trade manager at Petrobras Distribuidora, Ilonir Tonial. Traditional tarmac, in turn, is a mixture of Asphalt Cement with gravel. This mixture, heated, is placed on the road surface. According to soil conditions, it is necessary to add clay or gravel before tarmacking. This composition, however, be it for use with rubber or not, should be dimensioned while building a highway, considering the flow, weight, soil, etc.
Petrobras Distribuidora started trading rubber asphalt in 2001 and, according to Tonial, the demand is on the rise. The future demand, however, should depend much on economic factors. The consultant stated that the ecological factor is important, as production eliminates a residue of the auto industry, but price is very important for the market. When, for example, inputs used in Asphalt Cement, connected to oil, are higher, rubber asphalt becomes more attractive. He does not discard the potential arrival of new products, with better performance, to compete in the market.
Rubber asphalt, despite providing its contribution to the environment, represents a small share of the universe of reuse of tyres in Brazil. Reciclanip, an organisation that operates in the collection and distribution of tyres for reuse, collected 89,000 tonnes in the first quarter of this year. If all the material were made into raw material for ecologic tarmac, it would be possible to resurface 18,000 kilometres. The reuse of tyres in the country goes from use for production of sports courts, car mats and rubber soles, to the generation of fuel for the cement industry. The latter presents the greatest demand.
*Translated by Mark Ament
