Lehde took part in a demanding building project, in the course of new construction and modernization works carried out at the service area “Sauerland Ost” in Lüdenscheid (Germany). The specialist in precast concrete based in the city of Soest manufactured for Straßen. NRW (a State Government enterprise for road construction and maintenance) a visually appealing cladding for a large “bored pile wall”, serving as a retaining wall. For Lehde this was nothing special, actually, if there would not have been an elaborate textured formliner used for the 478 m² large surface. The Reckli formliner 2/164 “Brabant” features a surface with the look of rubblestone.
The Soest-based specialist in reinforced concrete needed about nine weeks only to produce the total of 49 wall panels. “Each component is really unique because the wall built at the service area has an inclined surface, in order to compensate the rough ground. Though the concrete panels have an equal thickness of 28 cm and are 1.98 m wide, they vary in height between 1 m and almost 7 m,” stated Patrick Beckmann, construction engineer at Lehde. The rubblestone pattern of the retaining wall features varying relief depths of between 8 and 43 mm. Therefore, the highest degree of precision was required from the workers of the Soest-based company with a long tradition, so that the retaining wall would not show any steps later. Every concrete panel has to fit exactly to the next one without offset – even along a length of some 100 m.
In principle, the production process is similar to that of any other precast reinforced concrete part. However, requirements are very special when it comes to the formwork: The textured formliner is inserted in the formwork like a kind of large rubber mat on which the concrete is poured. The elastic formliner creates the surface pattern and can be reused later for the next component.
“In this way, we are able to produce almost any surface texture, thus turning every concrete panel into a real eye-catcher,” Beckmann says. Working with formliners is nothing special for Lehde. Such orders are placed with the Soest-based, long-established company several times a year. “However, we rarely get such complex orders,” the construction engineer states. Upon request of the client, in the last working step a graffiti protection was additionally applied to the 49 wall panels, in order to protect their aesthetic impression sustainably. The clear coating ensures that the pores of the concrete are closed, making the wall less sensitive to weather conditions. Moreover, any unwanted scribbling can easily be removed.