Groundwater, under pressure, had penetrated between the reinforced concrete and the steel plates that formed the final lining towards the tunnel. Water was emerging from the joints between the steel plates and not only accelerating steel corrosion but affecting the operation of the metro. Using an injection technique with a combination of a foaming and a flexible polyurethane the joints were sealed and the water ingress was stopped.

Cracks in the concrete walls of the digester tanks, if unsealed, would have permitted the leakage of sewage under treatment. Due to the pattern and location of the cracks, it was neccessary to use a combination of rigid and flexible resins. The selection of resin was based on whether the point of injection was to form a single rigid element or whether to allow for movement. Thanks to MCBauchemie’s wide range of products, the engineers could easily select the most appropriate material and consider all design factors.

The concrete bridge, built in 1997, exhibited an unacceptable degree of cracking. The decision to inject the cracks was prompted by the need to prevent further opening of the cracks and the resulting risk of steel reinforcement corrosion. The selected material had to offer a high permeability, a high compressive strength, good bonding properties and cure to form a rigid seal. The use of MC-DUR 1264 KF epoxy fulfilled all requirements and achieved an estimated void filling of 95%.

The extension of the high-speed railway Brussels - Liège - Cologne made it necessary to replace an old railway bridge, trying to cause minimum interruption to rail traffic. For this reason only one half of the bridge was removed after the ballast on the other half had been stabilised by spraying with MC-Injekt 2700. The short time slots between passing trains and the requirement for reliable, rigid ballast bonding required a fast reacting, rigid elastomer resin: MC-Injekt 2700 was the perfect choice in this scenario.

The leaking ring joints were injected with MC-Injekt GL-95 TX, using a two-component highpressure pump via packers that had been placed into the ring joints between the steel segments. Damp areas were sealed with the 'curtain' technique via packers placed in a grid scheme.