Challenge

In Germany, many bridges, tunnels, and other traffic structures are in poor condition due to pollutants from the environment. Chlorides in particular can severely damage concrete structures by causing corrosion of the reinforcing steel. It is estimated that more than 60 percent of the damage to reinforced and prestressed concrete bridges in the German road network is due to chlorides. Thus, there is a great need for rehabilitation measures, but the methods available today often involve extensive intervention in the structure, making them expensive and lengthy. In order to cope with the rehabilitation backlog, new rehabilitation and reinforcement systems are therefore needed that can be used more quickly and cost-effectively than conventional methods.

Goals and procedure

The i-SCUP project will investigate the use of ultra-high-performance concrete (UHPC) for the repair of traffic structures. This innovative material will be used for the first time as shotcrete and applied in thin layers to shorten and simplify the repair process. On the one hand, the high-strength material is to fulfil a reinforcing function. On the other hand, since UHPC also has a very dense microstructure, it can reduce corrosion processes to a harmless level and protect the structure from the penetration of new chlorides.

In several work packages, the project team is working out the adaptation of UHPC to shotcrete technology, the possible areas of application, the necessary design approaches, and the essential material properties such as load-bearing strength, cracking and durability. Finally, a pilot project is planned with the cooperation partners to prove the practical relevance and feasibility.

Innovations and perspectives

The i-SCUP project combines two technologies that have so far been used separately: shotcrete technology, which has been tried and tested for several decades, and innovative UHPC technology with its high application potential. If these methods can be successfully combined, the chloride-contaminated concrete can remain in the structure in the future, which will significantly facilitate and accelerate repair. Another advantage of repair with UHPC shotcrete is its durability: while conventional repair methods can often only contain the problem of corrosion for a limited time, this resistant technology makes it possible to fully utilize the planned remaining service life of structures. In the long term, UHPC shotcrete technology is expected to clear the repair backlog on German transport structures via lower costs, faster processing, and longer durability.