Liapor

Integrally colored lightweight concrete for award-winning fire station

In the alpine village of Vierschach in South Tyrol, Italy, a new fire station was recently built for the community of Innichen, at an elevation of 1,130 m. The building stems from the pen of Pedevilla Architects, based in Bruneck in South Tyrol, who had won the competition for its construction in 2011. The monolithic architectural concrete building was conceived as a clean, compact structure that radiates solidity and strength. The rose-hued coloring emphasizes the self-sufficiency of the new building that, as a narrow block directly adjacent to the main road, at the same time blends confidently into the existing housing development.

Due to the steep slope on which it is built, the building is divided into an upper story facing the street and a basement level that faces the rear. It accommodates the vehicle hall with functional and ancillary rooms, while the floor above has a tea kitchen and a hall with room for 120 persons. Both levels are connected to each other via a helical staircase. “Special emphasis was placed on obtaining a robust and simple construction,” explains architect Alexander Pedevilla. “That is the reason why structural lightweight concrete was used.”

High-strength, lightweight, and thermally insulated

A total of around 568 m³ of close-textured architectural quality LC 16/18 Liapor reddish lightweight concrete went into the construction of the building shell of the new fire house. The concrete consists of Liapor expanded clay F3 aggregate, with 4/8 mm round grain, lightweight sand 0/2 mm, cement, water, and superplasticizers. Apart from a strength class of LC16/18, the concrete has a density of less than 1,250 kg/m³ and thermal conductivity λ of just 0.4 W/mK. Liapor developed the mix design in close collaboration with the company Summerer Hansjörg & Co. OHG in Sexten, Italy, which manufactured and delivered the concrete. The concrete test cubes were manufactured at the site and a test wall was built.

Minimized energy costs

The high strength of the Liapor concrete and its low weight enabled unsupported beam spans of up to 27 m in the interior of the building. The exterior walls have a thickness of 60 cm, thus meeting the energy specifications for public buildings. Owing to the use of the lightweight Liapor expanded clay spheres as artificial lightweight aggregate in accordance with DIN EN 13055, and in line with their national technical approval, the concrete features highly insulating properties, eliminating the need for additional insulation.

“All surfaces of the building are of pigmented concrete, accentuating the monolithic character of the building. The thickness of the wall can still be recognized and emphasizes the massive appearance of the fire station,” says Alexander Pedevilla. “Added to the thermal insulation properties is the especially high heat storage capacity of Liapor lightweight concrete, which results from the fine, porous inner structure of the expanded clay spheres,” explains Franz Fuchs of Liapor Österreich GesmbH. “This allows the entire monolithic building to act as a large heat storage unit and further minimizes energy costs.”

Award-winning pioneering construction

Liapor lightweight concrete, in addition to its structural function and its insulation properties, also provides a frostproof façade, ensures a long service life, requires low maintenance, and not least conforms to the highest fire resistance class A1 in accordance with DIN 4102. The fire station was built between August 2014 and January 2016. All exterior walls were formed with conventional form panels. Special emphasis was placed on obtaining a symmetrical formwork pattern. This, together with the configuration of the building, results in an especially uniform, harmonious façade pattern. Finally, the exterior surfaces were post-ground and hydrophobized.

The result is a building that combines color, shape, and function in a very special way and that, as the first public lightweight concrete building in South Tyrol, has already won many prizes: such as the German Design Award Gold 2017, the Piranesi Award 2016, and the Iconic Award 2016.