The history of bitumen

Bitumen is a hydrocarbon that owes its existence to the seedling accumulated and buried at the bottom of sedimentary basins. It is composed mainly of 85% carbon, about 15% hydrogen and 3% oxygen, sulphur and nitrogen. Bitumen is found outdoors, as in the United States and France, or in underground deposits in porous rocks, notably in Canada and Madagascar. This mixture of bitumen and limestone rock is called natural asphalt.

Bitumen is a road material that has always been exploited. His qualities have been recognized from Noah's Ark through the gardens of Babylon. The Egyptians also used it to cover the sacred ways of temples. Due to its adhesiveness, impermeability and malleability, it has long been a recognized raw material in the Middle East economy. In addition, doctors have found antiseptic properties. Dentists, for example, treated cavities with a mixture of bitumen and clay. It was at the end of the 18th century that bitumen arrived in France for printing inks or for waterproofing fortifications. Today, over 85% of bitumen production in Europe is used for road and urban road construction.

Other anecdotes highlight the properties of bitumen. For example, the first photograph in history was taken by Judea that Niepce with bitumen: he placed lithographic stones covered with bitumen at the bottom of a darkroom and then obtained a still image. In addition, bitumen is also an excellent thermal and electrical insulator: 450,000 km of submarine cables, containing a large part of the world's communications, are protected from corrosion and abrasion by bitumen. The latter is also known for its phonic properties. It is cast into the board and used to reduce noise propagation. As for its usefulness in the automotive industry, it can damp vibrations, particularly via so-called bituminous damping elements. In conclusion, bitumen has improved living comfort and energy savings. As a result, our mobility is constantly improving, whether on foot, on two or four wheels, whether the machine is powered or not.

Bitumen is mainly used in the world of road construction and is used to supply our professionals with bituminous asphalt binder. The rise of mobility around the world, and more particularly the development of the automobile, is closely linked to the expansion of the use of bitumen. Indeed, its use in the world road has helped solve the problem of dust on roads caused by traffic on the tarmac. Gradually, bituminous pavements covered roads all over the world, almost all roads. It was then naturally, through its many indisputable properties, that bitumen replaced tar after the Second World War. As a result, its industrialization was inevitable. The increase in demand and the expansion of the road network has led to better quality and productivity, while improving the living and working conditions of workers. Bitumen reserves are not unlimited, unlike demand. As a result, bitumen had to be produced by distilling crude oils. In the 1960s and 1970s, there was a desire and resources made available to improve the quality of materials. After the first oil shock, bitumen became expensive because it had to be saved. As a result, current asphalt mixes are composed of 95% aggregates and 5% bitumen. Noted that the latter is pure in the majority of cases. It is estimated that 10% of the bitumen needed to build a road is mixed with other products to alter its performance. For example, polymers are used to improve mechanical performance or resins are used to improve adhesion. Of course, all these processes are controlled and subject to strict health, safety and environmental standards.

Bitumen and sustainable development, is it possible?

The construction sector has faced many challenges in recent years. It must combine performance, prevention, savings in consumption of natural resources and reductions in greenhouse gas emissions and energy consumption. As a result, significant resources are devoted each year to research and development of new applications. Sustainable development is now a central objective. Reduced temperature techniques have been put in place and will probably be irreversible in the medium term. Moreover, by lowering the temperature at which asphalt is manufactured and applied, the reductions in greenhouse gas emissions and energy consumption amount to around 40%.

Bitumen must be used with care. Its high temperature increases the risk of burns. It has therefore always played an important role in companies' prevention policies. It is hot handled in every stage, from its manufacture to its application on the roads. Therefore, in addition to burns, workers are at risk of respiratory irritation. However, the temperatures currently used greatly reduce this risk. Moreover, unlike tar, bitumen is not carcinogenic. So it's interesting to look at the laboratory studies. One of the most important was conducted in Germany by the Fraunhofer Institute in 2017. Rats breathed smoke at a higher level than measured on site. By comparing this group to a control group, no carcinogenic disease developed because of the product. Other studies have taken place around the world. The results converge: professionals are not overexposed to bitumen and there is no direct link between lung cancer development and exposure to this hydrocarbon.

Bitumen is therefore a product used and necessary since Antiquity since we owe it considerable advances such as painting, insulation, photography or the construction of our road network. Today, 85% of the bitumen mined each year is used for road construction. Due to its unmatched performance, bitumen will continue to be irreplaceable. In this context, progress in scientific research is fuelled by the road industry in terms of technology or health and discoveries are still to come.