TUNNELS RESTORATION

Hydrodemolition

Due to the geographical situation in Central Europe, the density of road and rail tunnels is extremely high compared to other parts of the world.

For the construction of these tunnels, concrete was mainly used as a material, in combination with reinforced iron. In addition to natural aging (the so-called carbonation), it is above all environmental influences (static overloads or salt spreading) that cause damage to the concrete and the reinforcements. To ensure the safety of tunnels, timely and professional remediation of concrete is required. The old concrete must be removed so that the old iron reinforcements are freed and cleaned, in order to be fully able to apply afterwards a new anticorrosive protection. A new concrete cover layer and a special coating can then be applied as well. The advantage in removing damaged concrete by high pressure water jets is a vibration-free process, which avoids tension cracks. At the same time, the reinforcements themselves are cleaned and freed from corrosion. The partial removal of damaged concrete is performed with a jet of water up to 3000bar and up to 400 liters / min, using special robots or manual lances.

Advantages

• Absence of secondary damage such as. new micro-cracks
• The very high-pressure water jet does not generate vibrations, so much that it does not induce tension cracks, nor an extension of the noise induced in the structure
• The resulting surface is rough and ideal for proper adhesion of the new concrete
• Deteriorated concrete is removed more easily due to its reduced resistance to pressure. In this way, selective removal is basically possible.
• Complete conservation of the existing reinforcements
• Effective cleaning of corroded steel reinforcement
• Solvent action on the chloride of the high pressure jet
• Increase in grip values

Fields of application

• Vertical hydro demolition and on intrados
• Different demolitions are possible with “roughening” up to “complete demolition”
• Creation of notches in the shell
• Hydro demolition of concrete in niches

References

9,000 m³ hydro demolition Brenner motorway A22 (Italy)
40,000 m² hydro demolition of the Arlberg railway tunnel
22,000 m² hydro-demolition of damaged concrete and hydro-scarification of Kaunas railway tunnel lining (Lithuania)
6,000 m² hydro demolition damaged concrete S16 Arlberg tunnel
3,000 m² hydro demolition and restructuring A22 Tusch tunnel and viaduct (BZ)

Surface rehabilitation and restructuring in tunnels

During the restoration of tunnels it is not always necessary to completely remove the concrete. Many times it is enough to remove the coating from the wall and apply a new one.

Before each new surface coating, it is necessary to prepare the base layer (concrete, steel, screed, etc.) in full compliance with the respective standards and directives. Optimal adhesion between the roadbed and the coating layer is of vital importance, as it can guarantee the execution of the work to perfection/in a workmanlike manner. By means of our robots and special vehicles, we always find an optimal solution for each project, in order to guarantee an optimal roadbed and a processing without creating vibrations. We can count on very professional experience in road tunnel restructuring. For railway tunnels we have already built various special systems for the residual removal or washing of walls during maintenance. (taking turns in working on one platform at a time, while other companies are working on the others.)

Advantages

• Various materials (grout, impurities, etc.) are completely removed from the road bed
• Old damaged coatings are removed completely or if necessary only partially
• Removed materials are vacuumed at the same time, if necessary
• Machinery for both large and small surfaces

Fields of application

• Removal of grout
• Removal of coatings
• Removal of plaster
• Opening of cracks
• Creation of adequate roughening

References

130,000 m² surface preparation of A6 TO-SV motorway tunnels
35,000 m² surface preparation of A1 Genoa motorway tunnels
185,000 m² surface preparation of tunnels A15 – La Spezia