Additives for Backfill
Additives produced by Maplad are designed to fill the annular gap between the soil and the tunnel lining to allow the TBM to advance. Their use makes it possible to prolong the hydration process by delaying initial and final setting times and improve strength by dispersing cement particles.
TBM SYSTEMTwo-component additive for backfill
Two-component cement grout injection system specifically formulated for consolidation of the back segment cast with TBM. The system consists of two components that are added to a normal cement mixture of water and cement: RETARD 72 Retardant and fluidizing additive based on high molecular weight polymers designed to increase the workability of cementitious mortars or grouts for injection , up to 72 hours after preparation. Silicasil TS/AC 32 A sodium silicate-based setting accelerating admixture specially formulated to accelerate the setting time of grout, used in TBM excavation, for backfill.
ADVANTAGES Retard 72
• Maintenance of workability in mortars for up to 72 hours • Absence of segregation during storage
ADVANTAGES Silicasil TS/AC 32
• Reduces the setting time of the grout after injection • Low viscosity to decrease reaction time • Unchanged effectiveness even in the presence of free water in the soil