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Bridge rehabilitation without closure and great expense: Is that possible?

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In Germany, many bridges are in need of rehabilitation. On the one hand, this is due to the increasing load they are subjected to, and on the other hand, because the waterproofing of the bridge superstructure is getting on in years. For safety reasons alone, rehabilitation cannot be postponed. Nevertheless, closed bridges and long detours or waiting times for road or train traffic are a problem. The closures are particularly necessary when the bridges are being rehabilitated from above. Added to this is the cost intensity of these measures. If, on the other hand, the work is carried out on the underside of the bridge, it would be cheaper and easier. However, for a long time, there was no suitable waterproofing that was thin-layered and yet resistant to frost and water.

Research for textile concrete systems aims to optimize bridge rehabilitation

Together with the Institute for Building Materials Research (ibac) at RWTH Aachen University, Bawax GmbH conducted a research project that aims to tackle precisely this problem. To this end, the team developed a special mortar that provides reliable waterproofing under arch bridges despite its low layer thickness. At the same time, in combination with a textile concrete shell, it is able to withstand the effects of rail traffic and frost. No easy task - and one that requires support. This, of course, comes from düna. Because our high-quality and versatile fastening solutions are also used in bridge renovation.

The reference application in Thüring succeeds with plaster dowels from düna.

In summer 2021, the first reference application with the newly developed mortar in combination with a textile concrete shell and the plaster dowels from düna will finally start. It is about the maintenance of an arched bridge. The bridge is scheduled for refurbishment by the local maintenance department of DB Netz. In order to be able to draw a comparison, the team provides one part of the bridge with the textile concrete shell and the mortar, the other part receives a classic renovation plaster. In both cases, the high-quality düna plaster anchors type M provide hold and stability. Here, the versatility of the düna solution and the wide range of possible applications is demonstrated once again. The düna plaster anchor type M has an integrated spacer. It characterizes the dowel and also shows itself as an important element in bridge renovation. With the help of the type M dowel, the plaster base is fixed to the arched bridge. It forms the basis for the plaster and ensures a good hold.

The reference application shows: The düna plaster anchors prove effective. When processing the masonry, on the other hand, major differences between the newly developed mortar and the classic restoration plaster become apparent. After six months, the experts notice that the textile concrete shell is dense and dry, while the renovation plaster layer shows damp spots and efflorescence.

Innovative research and development combined with düna's reliable and versatile products make it possible to find a maintenance solution that can both withstand the stresses of rail traffic and be carried out without closing the bridge. The process can also prevent or stop frost damage. The solution has thus proven to be forward-looking and practical.

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