Shotcrete-Technology ´06

High early strength sprayed concrete for concrete repair work under operating conditions

Dr.-Ing. Roland Bornemann, BoConsult, Kassel
Dipl.-Ing. Uwe Rubba, w+s bau-instandsetzung, Kassel
Dipl.-Ing. Peter Löschnig, Sika Deutschland, Stuttgart

Many transport waterway engineering structures, like lock systems that have just one lock chamber for instance, cannot be completely closed down when maintenance work needs to be carried out, but can at most be put out of operation for a few hours of the day or night. In view of the age of these systems and the resulting condition of many locks, the problems associated with this issue are coming to be seen as increasingly significant. The Bundesanstalt für Wasserbau (BAW) [Federal Institute of Water Engineering] therefore commissioned feasibility studies for the projected work. A comparison of the different options showed that the use of sprayed concrete represents the best possible strategy for carrying out repair work under operating conditions. A prerequisite for the realisation of the project was the development of a high early strength sprayed concrete, so as to make it possible for traffic to be resumed after a setting period lasting just four hours. A pilot project has demonstrated the feasibility of the method envisaged and the suitability of sprayed concrete for this purpose.