Asphalt and its grip characteristics count for setup and performances

ASPHALT

TKART Staff

07 September 2017

When it comes to techniques regarding karts, the discussion always revolves around engines, chassis, tyres, etc. However, asphalt and its grip characteristics also counts. The characteristics vary depending on the construction and materials used

WHAT IS IT?

HOW DOES IT WORK?

IN PRACTICE

On the one hand you have the mechanical vehicle, with all its components, and the driver. On the other hand ... the asphalt. In fact, the surface of the track is really one of the main protagonists of every wheels based competition, and it therefore deserves to be paid the right amount of attention. Also because, depending on the applications for which asphalt is used (from city roads, motorways, tracks, etc.), the materials and construction techniques change, meeting specific needs and trying to support the characteristics of the vehicles that will travel on those roads.

The asphalt used on tracks and, more specifically, in karting circuits, has certain characteristics,

in particular, asuring two aspects: grip and resistance.

It fact, it should be empha

sized that karts, due to their low weight, generate a very low vertical load (on the contrary, for example, to a lorry driving on a motroway), and a very high tangential load due to the strong tyre grip of karts and the high speeds on bends. This situation is extremely critical for asphalt which, on the one hand, is not compacted sufficiently; on the other hand, its surface layer is literally ripped off by the tyres.
It is therefore interesting to know the logic of realising an asphalt circuit and to learn to have an initial indication of its characteristics even after a visual inspection.

ASPHALT CONSTRUCTION MATERIALS AND TECHNIQUES AFFECT GRIP AND RESISTANCE

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WHAT IS IT?

HOW DOES IT WORK?

IN PRACTICE

COMPOSITION

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USE

The more road level is superficial, the more inert components need to be small

PROBLEMS

Heavy vehicles passing over asphalt can cause cracks in the asphalt base layer

On tracks, grip and speed generate tangential loads that "rip off" the asphalt

Asphalt consists of two components: inert material, that is, the solid part formed by stones, and bitumen, the liquid part (or liquid while being subject to high processing temperatures).
The stones that make up the inert material range from a few mm to 30 mm in size, depending on their use. In addition, the inert material changes: it may be softer and more economical, that is calcareous, lighter, almost white or harder and more costly, that is basaltic, with a colour that is a shade between grey and black. Be careful not to be fooled by dark stones that are simply coloured by black bitumen.