Durable surface repair of waterway engineering structures with sprayed textile reinforced concrete

Many existing waterway structures are currently in need of maintenance and repair. The current surface repair methods include anchored, steel reinforced concrete or sprayed concrete procedures but are at least 90 mm thick due to the concrete cover. Alternatively, thinner, non-(steel) reinforced, non-anchored layers using sprayed polymer modified mortar or concrete can be used. However, a snap-through of the cracks into the protection layer and thus a reduction of the intended service life cannot be ruled out. Therefore, at the Institute of Building Materials Research (ibac) of the RWTH Aachen, DURTEX, a durable, water-impermeable and crack-spreading protective textile reinforced concrete layer was developed for the surface repair of waterway engineering structures. This paper introduces the proposed principle for the surface repair of waterway engineering structures with a low concrete compressive strength as well as a low surface strength, crack widths ranging from 0.1 to 3.0 mm and cyclically opening cracks and construction joints up to 0.5 mm. Furthermore the components of the developed DURTEX-protective layers within the framework of the transfer project T09 funded by the German Research Foundation (DFG) "Textile Reinforced Sprayed Mortar Layers for the Surface Repair of Waterway Engineering Structures" for the surface protection of the old concrete classes "A2" and "A3", without hydrostatic water pressure, with which a crack bridging up to 0.5 mm has been achieved are presented.