S&P Asphalt reinforcement
Fibre reinforcement grids for asphalt surfaces
The Formula 1 Azerbaijan Grand Prix has been held at the Baku City Circuit since 2016. The street circuit - only one of three on the Formula 1 racing calendar - runs through Icheri Sheher, Baku's historic old town, among other places.
The old town centre is disected by numerous historic cobblestone streets, which posed special challenges for the race circuit planners. All the more so because Icheri Sheher has been a UNESCO World Heritage Site since 2000. In order not to jeopardise this status, it was necessary to comply with UNESCO requirements that the racetrack could be dismantled without leaving any residues after its use had ended. This required the spatial as well as mechanical separation of the historic paving from the asphalt structure of the race track. In a realistic framework, this could only be solved by a separation layer of chippings - which, however, provided a new challenge.
Due to the extreme loads exerted by the racing vehicles in the winding old town circuit - up to 4.5 g in braking zones and curves - there was a risk of the asphalt structure tearing or being pushed up as it would be decoupled from the substructure. In search of a solution, the engineering firm Hart Consult International GmbH, which was commissioned with the planning and project management of the race track, turned to S&P Clever Reinforcement GmbH.
In close cooperation between Hart Consult International GmbH and S&P engineers, a concept was developed to meet the challenges. It was planned to reinforce the three-layer asphalt structure in the particularly stressed areas such as curves and braking zones with S&P Carbophalt® G 200/200 asphalt reinforcement. The aim of using the asphalt reinforcement was to distribute the extreme loads caused by the racing vehicles over a larger area and to anchor them in the component. This was to counteract damage to the asphalt package lying decoupled on the chippings bed.
For this purpose, the fibres of the reinforcement must be very stiff (high modulus of elasticity) and have a high tensile strength in order to be able to absorb large tensile forces even at very low elongations. Furthermore, a high bond of the fibres in the asphalt as well as a high mechanical bond between the asphalt layers is necessary. S&P Carbophalt® G 200/200 is a reinforcement grid of carbon fibres in longitudinal and transverse direction. The extremely high modulus of elasticity of the fibres (>240 000 GPa) allow a tensile strength of the grid of 200 kN/m at a maximum elongation of <1.5%. Due to its adaptable grid structure and bitumen penetration, a very high bond between the fibres and the asphalt is created, which means that they can be activated immediately when forces act on them. This makes S&P Carbophalt® G 200/200 ideal for reinforcing asphalt structures subject to the highest loads.
The high demands of racetrack construction required additional dimensioning including mathematical proof of the suitability and performance of the reinforcement to be used in the asphalt component. This could be provided by the S&P engineers due to their extensive expertise in the field of static reinforcement in reinforced concrete construction. The design was carried out in close cooperation with the experts of Hart Consult International GmbH, who were able to provide the decisive information regarding the driving dynamics of the racing vehicles and the framework conditions to be considered for the calculation. A detailed description of the design concept used is available from S&P on request.
What was initially planned as a temporary measure has now been proving its worth for a long time. Since 2016, the asphalt construction reinforced with S&P Carbophalt® G 200/200 has not only been provding valuable security during the annual Formula 1 races, ensuring the safety of the drivers, but the track sections are also subject to the stresses and strains of daily road traffic in Baku during the non-racing periods and perform just as well - albeit less glamorously.
5 000 m² - S&P Carbophalt® G 200/200
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