Bentonites
During excavation, use of a bentonite mud aids the underground excavation. The slurry is prepared with the aid of a bentonite mud which must meet certain specifications, according to the geology:
- Yield point
- mud viscosity
- Filtrate volume...
CONDAT is a representative for a range of bentonites selected for its very high quality and exceptional performance:
- high viscosities and yield point, even at low concentration
- very low filtrate
The bentonite is offered in 3 grades:
- Nanogelube for bentonite slurry used at the tunnel face
- Nanogel grout for mixtures with cement
- Nanogelgrout+ for bi-component grouting
Slurry mud additives
To reinforce the properties of the bentonite, CONDAT also offers additives with the CONDAT SLURRY IMPROVER CSI range
The CONDAT range of additives for slurry muds is designed to ensure several functions:
| Unclogging |
| Thickening |
| Filtrate reducing |
| Anti foam |
| Hyperbaric intervention additive |
Mud treatment
After excavation, the mud is conveyed or pumped back to a Separation Treatment Plant (STP); it must be recycled to optimise bentonite consumption and ensure the productivity of the tunnel boring machine.
For slurry tunnel boring machines, CONDAT offers different additives for treatment of bentonite muds according to the geology encountered and the required characteristics.
The separation treatment plant may need:
- unclogging polymers
- polymers for mud contaminated by cement or silicate
- polymers to reduce the use of lime in the press filter
- polymers to avoid the use of lime for the separation by a press filter
