Buenos Aires, Argentina
- Considering the huge importance of the soil conditioning during TBM excavation, especially with this specific type of TBM (EPB), and the big influence of the foaming agents that may be injected to the excavation chamber during excavation, the site management decided to carry out different products from different suppliers in the area, before choosing the most appropriate.
- The owner of the project had specific requirements considering the quality of the final concrete segments in this jobsite. During fabrication of the over 30.000 single segments (each with around 1 m³ of concrete), high early strengths were expected to reduce the curing time, allowing fast demolding. Additionally high requirements considering the performance and durability of each concrete segment were required too.
Our Sika’s local team and the Sika TBM Corporate experts recommended and tested together with the TBM team our basic foaming agent Sika® Foam TBM 101 FB-A, which is a high efficiency foaming agent for ground with high to low permeability and polymer modified. The dosage of the foaming agent was optimized as much as possible, always trying to keep the average advance speed of the TBM and most important, keeping the torque of the cutting wheel as low as possible. During tests, it was proved that the quality of the foam was very strong and fulfilled the expectation of the TBM drivers.
A leader German supplier of TBMs has provided an Earth Pressure TBM (known for its EPB technology) of around 6.0 m of diameter and almost 70 m long TBM to excavate the 5.9 km of the tunnel below the city of Buenos Aires. Excavation started inside an impressive 30 m depth shaft where the machine had to start excavation facing up to 3 bar water pressure in the mixing chamber. During full excavation, the machine can reach 20 – 25 m of tunnel per day.
Admixtures for concrete segments
Sika® ViscoCrete® WR-2000 and 2700 were used in the production of high-performance concrete, especially in concrete factories where the concrete are characterized by their low ratio water/cement, high cohesion and easy compaction. Additionally and only in special cases where the surface finishing of a few segments had to be improved, the Sika MonoTop®-620 was used with success.
Sika® Foam TBM 101 FB-A
Sika® ViscoCrete® WR-2000
Sika® ViscoCrete® WR-2700
City of Buenos Aires, Argentina
Jose Cartellone Construcciones Civiles S.A.
Benito Roggioe Hijos S.A.