Empa is replacing bitumen in road construction with string
At Empa, research is being carried out into a method of binding road surfaces using twine instead of bitumen. The stones of the driving surface should be stabilized by a thread net. That can make building more environmentally friendly.
Researchers at the Eidgenössische Materialprüfungs- und Forschungsanstalt ( Empa ) are currently examining a new method for stabilizing the amount of stone in road construction. Specifically, according to the press release, it is about replacing the bitumen binding agent in the production of the driving surface. Asphalt consists of stones of different shapes and sizes and only becomes a surface that can be used for roads when it is stabilized with the help of bitumen.
Bitumen causes environmental problems. Air pollutants are released during production from crude oil and later during use. Asphalt is also prone to cracks and deformations and impermeable to rainwater, which pollutes the environment.
The two Empa researchers Martin Arraigada and Saeed Abbasion from the concrete and asphalt department at Empa are currently implementing a method known from art for the production of road surfaces in a test arrangement. In such art objects, stone steles have been used, which are stabilized by a weave of twine and withstand loads of up to 20 tons at a height of 80 centimeters.
In the experiment, an electronically controlled robot arm applies a string to a stone layer in a specific pattern. By “interweaving” the stones are fixed in five layers in their position in the “road bed”. In tests, these were already as strong as conventional bitumen asphalt under loads of half a ton. Inexpensive twine was used, such as are conventionally used for tying up packages.
The trials have not yet led to a ready-to-use product that could be used in road construction. The basic work, however, provides a lot of innovation potential in order to get closer to a recyclable and perhaps rollable road surface using simple means, according to the Empa announcement. A video of the procedure can also be viewed on the website.