Mastic asphalt stove

Mastic asphalt cooker with vertically mounted stirred kettle

A mastic asphalt cooker is a mobile device for transporting mastic asphalt. He is either a truck - chassis , a trailer or a suppressible swap mounted. During transport, the mastic asphalt is constantly heated and mixed by an agitator.

technology

Mastic asphalt is produced in fixed or portable asphalt mixing plants and consists of a mixture of bitumen , sand, grit , stone dust and additives. During transport to the construction site, this mix of different grain sizes must be constantly distributed evenly so that the coarse aggregates (chippings) do not sink to the bottom of the boiler. Mastic asphalt cookers are therefore equipped with a slowly rotating agitator. These agitator shafts are fixed in ball bearings and made of heat-resistant steel. They are mostly driven by sound-insulated diesel engines, with some models by the running truck engine. The kettles can be tilted a few centimeters in order to be able to better empty residual quantities; the diesel engine also drives the hydraulic pump required for this .

Mastic asphalt has an ideal processing temperature of 220 to 235 ° C. The boilers must therefore be heatable for transport. A gas burner system is used for this , which is thermostat-controlled and keeps the mix at the desired temperature. This heating is supplied from gas tanks, which are usually painted red, which are mounted on the chassis. Small burners in particular also have replaceable gas bottles . Alternatively , oil can also be used as fuel, which heats the stove via an oil burner . The current asphalt temperature and the working pressure are monitored by an alarm system with a display in the switch box and also in the driver's cab. If necessary, it can be connected to a data recorder, with which other relevant data, such as the operating times, can be read out at any time and forwarded via a data connection (e.g. via mobile phone). A safety shutdown prevents the cooker and the mix from overheating.

The boiler is usually made of 8 to 10 mm thick special steel and provided all around with rock wool or a comparable insulating material. Modern stoves have a shiny, relatively easy-to-clean exterior made of stainless steel . For weight reasons, the vehicle's fenders are usually made of aluminum. This basic structure is the same for all mastic asphalt cookers, but can be expanded with options depending on the manufacturer. This includes, for example, a side outlet that enables removal from the sidewalk.

Vertical mastic asphalt cookers on a tractor-trailer chassis and a tandem trailer

Finishes and capacity

There are two construction variants available:

• Standing, vertical mastic asphalt cooker: The cooker is installed upright on the chassis; the capacity is limited by the permissible total height of the vehicle. Depending on the type of truck or trailer, a transport volume of between 200 and 6,200 liters is common. Therefore, the short chassis of articulated vehicles are also suitable for standing mastic asphalt cookers . The paddle arms are attached to the top of the kettle.

Mastic asphalt cookers installed in a lying position enable greater transport capacities.

• Lying, horizontal mastic asphalt cooker: Since the cooker "lies" here on the chassis, the entire length of the loading area of ​​the vehicle can be used. Therefore, large semi-trailers are also suitable for this structure , with capacities of up to 12,000 liters. The agitator arms or agitator shafts must be attached horizontally. Since they are in the hot mastic asphalt area with this variant, they must be carefully sealed with special, temperature- resistant stuffing boxes . In order to be able to reach the filling flap safely, horizontal mastic asphalt stoves usually have a fixed ladder and a small platform.

Transport from the mixing plant to the construction site

The transport of mastic asphalt over long distances is not a technical problem, but it is uneconomical. That is why there is a network of asphalt mixing plants in Germany. Each construction site can thus be reached in around 150 km on fresh asphalt. There are around 4,100 asphalt mixing plants in Europe.

On smaller construction sites, the asphalt is brought from the mastic asphalt cooker to the installation site by wheelbarrow and spread by hand by strings.

Transport on site

The further transport of the mastic asphalt at the construction site depends on the local conditions:

• On small construction sites, the mastic asphalt is drained from a hydraulic spigot on the cooker into wooden buckets (sometimes also into removable chutes ) and brought to the installation site by the so-called carrier with a support yoke, carrying a total weight of up to 60 kg. There the asphalt is spread by hand by the so-called smoothers (also known as strings ) with wooden spreaders . To estimate the correct thickness (3 to 3.5 cm), it is necessary that straighteners work mostly on the knees. On small, ground-level construction sites, wheelbarrows are used instead of the carrying yoke .
• In higher structures, for example on parking decks, the asphalt can be pumped directly from the mastic asphalt digester with special, mobile mastic asphalt pumps up to a height of 20 meters. If the use of such pumps does not seem economical, the asphalt, including the bucket or wheelbarrow, is pulled to the desired height with a construction site elevator or crane.
• On larger road construction sites, the asphalt is unloaded from the vehicle directly in front of the self-propelled mastic asphalt screed . For the production of an even road surface it is necessary that this screed is continuously supplied with asphalt for the entire installation period. To ensure this, a sufficient amount of material must be kept ready at all times; Recognizable at larger road construction sites by the large number of waiting mastic asphalt cookers.
• Special front tippers (dumpers) have been developed for larger construction sites that cannot be used by trucks, for example underground garages or narrow bike paths . These are small, very manoeuvrable mastic asphalt cookers with a short wheelbase that can be moved even in the tightest of spaces; they can transport up to 600 liters.

Picture gallery

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  Mastic asphalt cooker 1880: The asphalt was heated with a wood furnace, the agitator operated by hand.

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  Horizontal asphalt cooker 1920s on Freedom Square in the city of Kharkov (now Ukraine).

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  Vertical mastic asphalt boiler 2010 on a Russian KAMAZ chassis in Kraków (Poland).

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  Mastic asphalt cooker in front of a mastic asphalt plank on the Rügen Bridge 2007. The cooker can be raised to empty.

Others

• Colloquially, mastic asphalt cookers are still often referred to as tar cookers . The term tar column is also often used on construction sites . However, since 1984 tar has not been allowed to be used in road construction in Germany because of its harmful effects.
• In 2006, the Federal Labor Court dealt with the question of whether mastic asphalt cookers are to be judged legally as a transport truck or as a construction machine. On this question, which is relevant to the social security scheme in the construction industry, the court comes to the judgment that mastic asphalt cookers are not trucks that are customary in the industry, but special devices that can only be used sensibly for construction activities, namely to apply asphalt to roads, bridges and interior floors ( Federal Labor Court judgment of August 2, 2006 - 10 AZR 756/05).

Manufacturer

In Germany, mastic asphalt cookers are produced exclusively in medium- sized companies :

• Altenwerder mastic asphalt Technology AGT, Seevetal
• Benninghoven GmbH & Co. KG, Mülheim
• Grün GmbH, Wilnsdorf
• Kolberg GmbH, Bispingen
• Linnhoff & Henne GmbH & Co. KG, Stadtoldendorf

literature

• Thomas Wörner, Jürgen Hutschenreuther: Asphalt in Strassenbau , 2nd edition, Kirschbaum Verlag 2010, ISBN 978-3781217829
• Eduard Zirkler: Asphalt - A material through millennia , Giesel Verlag 2001, ISBN 978-3878520108
• Hans Schmidt, u. a .: ZTV / TL Asphalt-StB, taking into account the changes and additions to ARS 29/2010. Status March 2011. Manual and commentary , 3rd edition, Kirschbaum Verlag 2011, ISBN 978-3781216808

See also

• Transport engineering
• List of construction machinery and construction equipment

Web links

Commons : Mastic asphalt stove  - collection of images, videos and audio files

• Generally understandable short film about the installation of mastic asphalt on a road construction site
• Generally understandable short film about filling a mastic asphalt boiler and working with a screed in a tunnel structure
• Altenwerder Mastic Asphalt Technology AGT website
• Benninghoven GmbH & Co. KG website
• Internet presence Grün GmbH
• Kolberg GmbH website
• Internet presence of Linnhoff & Henne GmbH & Co. KG

Individual evidence

1. ↑ Standard cooker ( Memento of the original dated August 30, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Internet presence of a manufacturer. Retrieved May 5, 2012.  
2. ↑ Transport cooker for mastic asphalt Homepage of a manufacturer. Retrieved May 12, 2012.
3. ↑ Locations of the asphalt mixing plants Internet site of the German Asphalt Association . Retrieved May 5, 2012.
4. ↑ Number of Production Sites ( Memento of the original from June 10, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 3.2 MB) Publication of the European Asphalt Pavement Association of December 22, 2011, page 5. Accessed on May 6, 2012. 
5. ↑ Hot mastic asphalt. Uploaded to YouTube on April 21, 2009. Accessed on March 3, 2012.
6. ↑ Asphalt transport cooker. (pdf) (No longer available online.) BG Bau, p. 1 , archived from the original on September 6, 2017 ; accessed on September 6, 2017 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
7. ↑ Herbert Leutert: Modern conveyor technology for mastic asphalt. The history of the development of the mastic asphalt pump . In: Asphalt . March 2007, ISSN  0945-6228 , p. 26-30 .
8. ↑ Mastic asphalt dumper homepage of a manufacturer. Retrieved May 12, 2012.
9. ↑ Hazards and protective measures in road construction ( Memento of the original from April 26, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Publication of the trade association for the construction industry, 2007. Accessed on May 6, 2012.  
10. ↑ Judgment of August 2, 2006 Az. 10 AZR 756/05. openjur.de, accessed on September 6, 2017 .