In industrial nations such as Germany, more road kilometres have long since been rehabilitated than newly built - and millions of tons of asphalt have been removed. This task is mainly performed by cold milling machines that load up to 3,000 tonnes of milled material onto trucks in a single shift at peak times. For a long time, such contaminated sites posed a challenge for road construction companies. In the meantime, however, recycling technologies are transforming the asphalt mix, consisting of rock of various grain sizes and the binding agent bitumen, into "black gold". In Germany alone, twelve million tonnes of recycled asphalt out of a total of 40 million tonnes per year are now paved by road pavers.
Reduction of emissions by means of countercurrent principle
With the new asphalt mixing plant BA 4000 from Benninghoven, the Max Bögl Group has achieved two central goals that go far beyond the legal requirements: On the one hand, the plant meets recycling quotas of over 90 percent, so that asphalt can be produced with a proportion of nine tenths of "old road". On the other hand, the innovative technology noticeably reduces emissions. This is made possible by a parallel drum in counter-current operation with a hot gas generator. The recycled material is heated in a drum to the optimum processing temperature of 160 °C for asphalt. In contrast to conventional asphalt production, the burner heats indirectly - with hot gases - so that the bitumen contained in the asphalt does not burn and at the same time the emission values are kept within the normal range.
World's highest recycling rate
This technology enables the Max Bögl Group, which has been operating an asphalt mixing plant at its Sengenthal headquarters for many decades, to achieve the highest recycling rates worldwide. Max Bögl is thus ideally positioned for the future - especially as ever stricter limits and recycling quotas are to be expected from legislators in the future. The profitable combination of sustainability and efficiency, based on innovative recycling technology, was therefore a decisive factor in the decision to invest in a completely new plant instead of modernising the existing one. A further argument: beyond the requirements for sustainable operation, the plant masters all relevant asphalt formulations and, with an hourly output of 250 tonnes, also fulfils the required production capacity.
Multivariable addition creates flexibility
However, the BA 4000 also integrates a second recycling technology: the multivariable addition, with which up to 40 percent of removed asphalt can be added cold to the production process. This means that even small quantities of mix weighing two tonnes or more can be produced, giving the mixers great flexibility. Thanks to the new high-performance plant, Max Bögl will in future be able to supply a wide range of road construction sites in the Nuremberg area with mix from Sengenthal - using its own thermal trucks.