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ITALIAN ASPHALT, TECHNOLOGY COMBINING TRADITION AND INNOVATION
Asphalt production is another field in which Italian companies play a major role, their expertise putting them at the forefront for innovation and technology. One does not have to actually go back to Roman times to recall the traditional skill of the ancient Romans in road-building. This is, however, clearly a type of “imprinting” which has been passed down over the centuries. Nearly 1,500 years after the fall of the Roman Empire, it was actually the Italians who “invented” motorways, or rather roads dedicated to the motorcar. “The ‘Milano-Laghi’ motorway, opened in 1924, was considered the first of its type in the world. It was designed by the Italian engineer Piero Puricelli, who completed it in only two years.” These were the words of Stefano Ravaioli, the Director of Siteb, the association representing manufacturers of bituminous concrete. Mr Ravaioli added: “Later on, at the time of reconstruction following the Second World War, we returned to the forefront in road construction and remained uncontested leaders in this field until at least the 1980’s.”
From that time onwards, new competitors began to challenge Italian supremacy, but during the 1990’s it was the Italians who again came up with new ideas to improve their product. As Ravaioli explained: “It was then that modified bitumen and porous asphalt made their appearance. These were amalgamates containing polymers which gave the substance extraordinary elastic properties absent in traditional asphalt.” Everything, therefore, revolves around bitumen, the most important material in road-building because it determines the performance of the road surfaces in terms of safety and efficiency, as well as in ecological terms.
Porous asphalt is a form of bituminous concrete containing holes to encourage water to flow away. The problem lies in making the substance in such a way that the constant pressure exerted by the weight of vehicles passing over it does not eventually lead to the asphalt becoming compressed and the holes filling up. As Ravaioli explained: “Porous asphalt was originally developed in Great Britain. But in the years 1985-87, the Italians rediscovered and reinvented this substance, enriching it with elastomeric polymers which were able to bond very strongly with the inert materials and keep the spaces open between the stones.” Nowadays, Italy is a major European producer of porous asphalt, with 80 million square metres of the substance laid on thousands of kilometres of roads. “One of the other bonuses of porous asphalt,” continued the Director of Siteb, “is its capacity to absorb noise: in fact, the presence of the holes reduces high frequencies making the asphalt less noisy when the cars pass over it.”
Porous asphalt does however present one problem: in snowy conditions the empty spaces lower the temperature of the road surfaces which consequently freezes earlier than traditional surfaces. It is important for the companies in charge of road maintenance to constantly monitor weather conditions and try to prevent the formation of ice by laying salt on the road surfaces. Ravaioli pointed out: “The companies have introduced a counter-measure specifically for these circumstances, mixing salt crystals in with the bituminous concrete and so lowering the freezing point to -15°C. This is a really efficient solution.” The fact that this porous asphalt performs exceptionally well is demonstrated by the example of the Brennero motorway. This crosses the Alps and is subjected to extremely low temperatures as well as frequent snowfalls. It is also totally surfaced with the freeze-resistant version of porous asphalt.
The Italian asphalt industry presently employs more than 500,000 workers and has a turnover of about 3,800 million Euros achieved by the approximately 4000 companies working in this industry. In 2008 asphalt production was estimated at between 32 and 33 million tons. Thirty per cent of the bitumen produced in Italian refineries is exported to Eastern Europe and North Africa. The most receptive export markets for this branch of Italian technology are some of the Eastern European countries, in particular Poland and Rumania, where, as Ravaioli noted, “the condition of the road network is very sub-standard.” Generally, the Italian sector exports polymers, bitumen modification systems and machines for manufacturing and laying asphalt.
The next goal is to introduce “intermediate” technology for laying asphalt. “Cold technology offers great advantages especially with regard to the reduction of CO2 and emissions into the atmosphere and yet is little used in our country,” said the Director General of Siteb. “Here, the use of hot asphalt definitely predominates, but Italy is making big investments in the so-called “tepid” method, which allows us to produce asphalt at about 100 degrees centigrade as opposed to the 160-170 degrees normally used for this process. By adapting the system, which would not require radical modifications, and changing the mix of materials, we could achieve savings of up to 30-40% in terms of energy consumption”, he concluded.