Tunnel injection of polyurethane foam resins in Spain

Polyurethane foam resins are designed to react with water and produce flexible or inflexible grouts suitable for sealing cracks and joints of concrete surfaces and for effectively stopping water leaks. These polyurethane foaming resins can be re-injected with polyurethane resins later for permanent waterproofing.

Project Requirements

In these particular tunnels in Spain the concrete structures needed immediate repairs due to leakage problems through voids and cracks in the concrete structure.

The influx of water was such that the best solution was to apply a tough expanding foam with low viscosity while it would be flexible enough for the permanent sealing of the leaks.


ALCHIMICA’s experts were able to provide the best technical advice and support recommending the optimal injection solution for this project. The range of injection hydrophobic polyurethane foaming resins, WATERFOAM was the best solution as it stops water effectively and seals cracks and joints of below-grade structures. The solution was able to form a new permanent watertight, seal and prevent future structural repair costs.

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ALCHIMICA’s below ground waterproofing solutions. Cut and cover tunnels application of the fast train line Paris-Barcelona.


One of the greatest projects in the railway industry which connects two beautiful and historic cities, Barcelona and Paris, is the high-speed train that was launched in 2013. The project was a joint venture between France’s state rail operator SNCF and its Spanish state rail operator Renfe. Since then, the TGV which is one of the highest speed trains in the world, along with the Spanish ones run between the French capital and the Catalan city each day.

Project Requirements

The fast train line Paris-Barcelona project included several cut and cover tunnels in domestic areas. In that type of application, external below ground waterproofing is paramount for the long-term stability of the concrete structures

Considering structural waterproofing and especially tunnel  applications, the waterproofing systems must be sustainable and deal with severe strict requirements for both the internal and external surface environments. The long – term durability of the structures is directly related with a water tightness plan to prevent water ingress and the deterioration of concrete.

External waterproofing systems must seal and secure the concrete and ensure the stability and longevity of the construction by minimizing future maintenance expenses. In tunnels the correct application of a waterproofing system is imperative, since performing repairs comes with a very high cost and effort. Without waterproofing, water penetration can cause structure destruction and concrete corrosion which means future intervention, increasing the maintenance costs. Thus, the long-term durability of the tunnel structure is related to a water-tightness plan that considers high quality waterproofing products.


ALCHIMICA’s external below ground waterproofing and protection system based on HYPERDESMO®-PB-2K meets all the necessary requirements of engineers and architects for waterproofing specific demanding areas. Our complete range of products includes highly flexible bituminous liquid membranes which are designed and fully tested for structural waterproofing applications.

Taking into consideration the critical point to deal with threats as unequal static forces, water ingress, aggressive chemicals, gas penetration, external mechanical pressures, and temperature variations we used MICROSEALER-50 as a primer, HYPERDESMO®-PB-1K to treat and seal the concrete dilatation joints and then followed the application of HYPERDESMO®-PB-2K applied in a single coat at the total required thickness.

Find more information about ALCHIMICA’s below ground waterproofing solutions. Contact us.

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