During the construction of the Tunnel de Champel in Geneva, MasterEase from Master Builders Solutions proved to be a well suited superplasticizer for sprayed concrete. MasterEase reduces the viscosity of the concrete, making it less sticky and therefore easier to pump and apply. This is a significant advantage for sprayed concrete applications. MasterEase UG 3904 increases the workability time and, when applied, the concrete hardens more evenly on the tunnel wall.
Thanks to the use of MasterEase, the Swiss tunneling contractor Marti Tunnelbau AG was able to switch to a more economical cement for the construction of the railway tunnel”. Initially, the change in cement presented some challenges: “The combination of the new cement and the old superplasticizer created problems due to the reduced open time,” said Nicole Kölbener, construction manager at Marti Tunnelbau. “After only one hour, the flowability was no longer sufficient.” René Bolliger, Head of Underground Construction at BASF for Germany, Austria, and Switzerland, recommended to the tunneling specialist and the cement supplier Holcim that the MasterEase UG 3904 superplasticizer should be added.
Kölbener is pleased with the outcome – the product worked extremely well with the concrete used, she said. Therefore thetunnellers were enabled to change the cement source: “This increased our profitability by five percent.”
Fabien Cerf, Head of Sales Geneva at Holcim Switzerland, stressed an environmental benefit: The cement comes from a cement plant that is only a few kilometers away. This eliminates the need for the 350 km journey to the old cement plant. “By changing the cement, we have been able to reduce costs and achieve a six-percent saving in CO2,” says Cerf.
For Bolliger, the successful outcome of this project shows how important it is for all project partners to cooperate closely: “We provide our customers with on-site support and are always available. As a result, we are able to work together in challenging situations to find the best solution.”
The 1631 m long two-track Tunnel de Champel is part of the CEVA project. This rail route will connect the Cornavin station in Geneva with Eaux-Vives and Annemasse in France. The breakthrough of the tunnel took place on June 8, 2017 in Carouge near Geneva, The CEVA line is expected to commence operation in 2019.