First publishedin Aggregates Business Europe & International
Optimum milling results have a significant influence on the quality and economic efficiency of the subsequent race track rehabilitation work. On Sachsenring, the Wirtgen large milling machines W 200 and W 220 handled the
A Benninghoven asphalt mixing plant, Wirtgen milling machines and Vögele pavers have been busy rehabilitating the legendary Sachsenring race track in Germany’s Ore Mountains so that it continues to meet FIM (Fédération de Motocyclisme International) requirements.
The demanding project taken on by the Wirtgen Group plant and machinery entailed replacing the famous race track’s surface and binder courses. While Wirtgen cold milling machines created a level base true to line and level through precision milling, a mixing plant from Benninghoven and paving technology from Vögele ensured the high quality of the mix and the paving work.
The smooth completion of the paving work owed much to the supply of mix, which was scheduled down to the last minute. Each day, some 1,300tonnes were delivered from the Benninghoven TBA 3000 mixing plant in Zwickau to the race track on 15 trucks, with an average round trip taking just under two hours. This enabled the client, in collaboration with plant operator Deutsche Asphalt, to supply each of the pavers continuously for 16 hours. The quality of the mix was a key concern. The mixing plant, for instance, had to use at least four screens to produce the mix for the surface course. In addition, at least five hot bins with filling level and temperature monitoring and an overflow were to be provided in order to ensure the purity of the fractions.
Carrying out a thorough check of the TBA 3000 prior to the start of the work, race track specialist Dr Rainer Hart said: “With six screens, the Benninghoven plant in Zwickau is outstandingly well equipped. It also has everything else that we need for our high-performance asphalt.” He ought to know, given that he developed the formula!
The production and silo capacity of the Benninghoven asphalt mixing plant was one of the relevant factors in the Sachsenring project. With the 3tonne mixer, a mixed material storage silo with four bins and direct loading, the TBA 3000 more than met the requirements
The world-famous expert praised the high precision of the plant in the coordination process: “The batch mix reports indicate that the fluctuations are well within tolerances.” Consistency of quality is particularly relevant when building race tracks, because the leeway is considerably smaller than when building public roads. To give an example, the proportions by weight of the individual fractions in the surface course must not deviate from the specification by more than 1.5-3%.
The burner of the plant, which was erected in 2008, can – as is usual in Germany – run on coal dust and oil. “It’s extremely sparing on resources,” confirms plant manager Heiko Reinwardt, adding: “Benninghoven produces by far the most economical burner on the market.” Once a year the Deutsche Asphalt team calls in a service engineer from Benninghoven to carry out a service. And if anything crops up in the meantime, “we just give them a call. Even remotely, Benninghoven answers the majority of questions fully and expertly.”
Just recently Gero Kretzschmar, an expert in industrial measuring and control technology and one of the mixing plant specialists at Wirtgen Zwickau, installed a rotary blower in the plant to deliver the coal dust from the silo to the burner. With a rotary vane feeder, this customised solution from Benninghoven ensures the freely adjustable supply of coal dust at a feed pressure of at least one bar.
The electrically heated bitumen tanks also contribute to the economical yet convenient operation. “This form of heating is cost-efficient, and we are saving on the cost of separate oil handling,” says the mixing plant team.
Thanks to the pinpoint asphalt production, thorough planning and the premium machines of the Wirtgen Group, the contractor was said to be able to meet the high requirements on the asphalt surfacing in every respect. The race track operators, racing drivers and motorsport fans should soon be able to look forward to some keenly-contested races.