Sustainable site expansion at Bau Beton in Vienna-Freudenau

Founded in 1997, Bau Beton, based in Sollenau, is a family-run company in cooperation with Salzburger Sand- und Kieswerke GmbH (SSK). Under the leadership of managing directors Josef Eder and Gernot Groß, the company employs around 100 people, most of whom work in the company‘s own delivery fleet, which currently consists of around 50 mixer trucks and eight concrete pumps. In addition to efficient concrete logistics, which make the company a reliable partner for major building, civil engineering and transport construction projects, Bau Beton has invested in particular in the modernisation of existing production sites and the integration of new ones over the past 20 years. This was also the case at the port of Freudenau, where a 60 m³/h mixing plant and a 90,000 m² site were taken over in 2011.

Leveraging location advantages

In addition to customer-focused delivery logistics, which are route-optimised and thus CO2-optimised thanks to central GPS-supported dispatching, and a wide range of production options, environmental protection and sustainability are other important guidelines for the company‘s activities. When the Freudenau mixing plant came up for renewal a good five years ago, Bau Beton opted for the big solution: a location close to the city centre with good transport links to the eastern hinterland. The location in the middle of the port area, with access to rail and shipping infrastructure, also offered the best opportunities for optimising the company‘s own supply chains in an economical and environmentally friendly way. A delivery depot was also built in Freudenau, with large storage capacity and loading facilities, which distributes binders and aggregates received by rail or ship to the surrounding Bau Beton plants or third-party customers.

SBM Mineral Processing was responsible for the design and implementation of the entire plant. In accordance with the customer‘s specifications and schedule, an integrated concept was developed that allowed the completion and commissioning of the new concrete production facility in several construction phases and sub-projects, and later the integration of handling facilities, storage and landfill capacities, including the necessary conveying and loading technology.

Following extensive ground reinforcement work, the first phase of construction of the new Freudenau mixing plant began in 2020. Production started in the summer of 2021 together with the old plant, which was dismantled at the turn of the year 2021/22. With concrete production in full swing, and in parallel with the completion of the jetty and railway siding, SBM installed the handling equipment and additional binder buffer silos last year, which were commissioned with the arrival of the first cement train in August 2022. Further expansion stages include the construction and connection of large external aggregate storage facilities and the flexible expansion of the cement silos by a further 500 tonnes.

More output – more variety

The increase in the output of the concrete mixing plant from 60 m³/h to a maximum of 165 m³ of hardened concrete per hour alone shows the potential that Bau Beton‘s management sees for the Freudenau site in the long term. Once again, great importance was attached to product diversity, which corresponds to the wide range of concrete applications in the Vienna area: In addition to large silo capacities for various binding agents (3 x 170 t + 2 x 85/85 t; expandable by 4 x 120 t), the plant is designed for the storage and use of various admixtures (7 x 2,500 l + 3 x 1,500 l) as well as for the addition of steel or plastic fibres and colour granules.

The technology of the new mixing plant is based on the stationary SBM series Linemix 4500 ST 1800 H with a 4.5 m³ twin-shaft mixer from BHS-Sonthofen and an aggregate silo volume of 1,800 m³. Thanks to the Linemix modular system, the plant could be configured exactly according to the customer‘s wishes in terms of construction and technical equipment. A solid three-storey plant building houses the social rooms, the control centre with a direct view of the truck mixer filling and the compressors for high-pressure cleaning of the mixer in the adjacent mixing tower. For year-round operation and to avoid emissions (dust, noise), the mixing tower and aggregate store are fully enclosed.

Finely dosed from the production silos, the aggregate components are weighed for the first time on a collecting weigh belt. They are then conveyed via the feed conveyor to the mixer pre-bin, which is also equipped with a weighing function for control purposes, directly above the mixer platform. This is also where the addition of binding agents, taken from the production silos via metering screw conveyors, and the admixtures stored at the top of the mixing tower are added. The entire production process is video monitored and can be viewed on a multi-screen in the control centre. The same applies to the concrete recycling plant with three washing stations for truck mixers and concrete pumps, which recycles washed aggregates and wash water back into concrete production.

To ensure year-round operation in Freudenau, but especially for the production of temperature-critical concrete qualities, SBM installed a combined heating/cooling unit for aggregates and mixing water from the Finnish manufacturer Polarmatic.

Good prospects

In regular two-shift operation, the entire plant is „driven“ by two mixing foremen and one site operator. During major projects – such as supplying shotcrete to underground railway construction sites – the teams switch to 24-hour operation.

The new binder handling and delivery terminal has also been operating at high capacity from the outset. In addition to noticeable savings in transport costs and CO2 emissions by eliminating truck transports – one train is equivalent to around 40 large silo trailers – the company is also opening up alternative sources of supply that were previously out of reach by road. This also applies to the delivery of aggregates by rail, which will start this year, and the planned start of deliveries by ship in the medium term.

The new accessibility also plays an important role in the possible expansion of recycling activities: clean concrete residues are to be accepted in Freudenau, processed in a qualified manner and returned to the concrete cycle as high-quality aggregates on site or in neighbouring plants. In addition to the space requirements and investments for the necessary processing steps (crushing, screening, washing), the expected delivery flows and quantities are currently being evaluated – as a prerequisite for good value creation by the new Bau Beton division, which is again consistently oriented towards high quality standards.