The Ammann plant was used for the work as it had the ability to produce a quality asphalt while using a high percentage of RAP in the mix.
The contractor was keen to use as much recycled material as possible as this would help to reduce the environmental impact of the project, with the use of RAP playing a key role in the asphalt production process.
The Ammann ABP 240 HRT was purchased by Pražská Obalovna Herink (POH), a business owned jointly by the contractors Skanska and Eurovia. About 90% of POH’s mix is delivered to its parent companies, with the remaining 10% used by smaller, individual customers. The firm acquired the HRT plant as it is able to use a high percentage of RAP in the feed and delivers a quality product, while having very low emissions. In addition, the firm was impressed by the reliability of the plant, as well as its energy-efficient operation. Another benefit of the plant that appealed to the contractor was its ability to produce mastic asphalt.
The Ammann ABP 240 HRT was delivered at the start of 2020 but its installation was delayed by the coronavirus, so the first mix was only produced a few months later. The new HRT technology provides a significant upgrade from the firm’s previous plant, which was more than 20 years old. The new plant features Ammann’s sophisticated as1 Control System, which has proven efficient and productive and makes RAP utilisation more simple.
The Ammann ABP HRT features an RAH100 drum, which allows indirect heating of the RAP. This means that the recycled material does not come in direct contact with the flame. The binder is not degraded and there are not high emissions. This novel counterflow drum allows the plant to produce asphalt mixture consisting of 100% recycled asphalt (RAP).
At present, Czech standards allow a maximum of 60% RAP into the mixtures for base layers, 40% RAP for binder layers and 25% for surface layers. But the firm expects these regulations to be modified in the future as the technology for the use of RAP becomes proven, which will allow the company to use higher percentages of RAP in asphalt mixes. The company has experimented with mixes containing much higher RAP percentages. A mix featuring 80% RAP was used for a private project, and the firm says that it is monitoring the performance very closely.
Current production is mainly focused on the modernisation of the D1 highway near Prague. The work calls for the improvement of 14km of road and is a high priority for the Czech Government as the highway is the main route connecting the two largest cities in the Czech Republic, Prague and Brno. In 2020, POH delivered about 100,000tonnes of mix for the D1 project, with another 50,000tonnes planned for 2021. The biggest challenge of this project is to finish work on time, without delays. The production capacity of 240tonnes/hour is helping the contractor to meet this challenge, along with its ability to use a high percentage of RAP while delivering a quality mix.
The plant will also be used to produce asphalt for other road projects in the area however, including work in the capital Prague and the central Bohemian region.
In the future, POH plans to produce wider scope of asphalt mixtures containing higher amount of RAP. The firm can link the plant directly to an external tank, which offers the ability to produce mixes featuring special asphalt binders.
The plant recently produced a mix using 90% RAP, which led to an award for innovation in the Czech Energy and Environmental competition, announced annually by TOP EXPO. A panel of experts evaluated the entrants and chose POH because of its advanced recycling efforts. The company credited the RAH100 drum on its Ammann ABP 240 HRT as key to its recycling success.