Concrete Accelerator (Shotcrete Set Accelerator)
Set accelerator for shotcrete, available as alkali-free liquid and low-alkali powder. Short initial set, high early strength and low rebound.
Overview
Accelerators make shotcrete set within minutes of application, allowing greater single-pass thickness and sharply reducing rebound. The alkali-free liquid type has little effect on later strength and a better working environment, making it the mainstream choice for tunnel and mining support.
Key benefits
- Fast set enables thicker single-pass layers and fewer re-sprays
- Low rebound means less material wasted
- Alkali-free type does not corrode reinforcement and retains 28 d strength
- Less dust, better working conditions
Application notes
Added at the nozzle; dosage is set on site according to cement type, temperature and spraying process. Alkali-free liquids are more sensitive to cement type, so run a trial spray first. Store away from alkaline materials.
Typical uses
Tunnel primary support and final lining, mine roadway support, slope protection, underground works, emergency strengthening.
Technical specification
| Type | Alkali-free liquid / low-alkali powder |
| Initial set | ≤ 5 min |
| Final set | ≤ 12 min |
| 1 d compressive strength ratio | ≥ 130% |
| 28 d strength retention | ≥ 90% (alkali-free) |
| Rebound reduction | 30% – 50% |
| Alkali content (Na₂O eq.) | ≤ 1.0% (alkali-free) |
| pH (alkali-free liquid) | 2.0 – 4.0 |
Standards
Applications
- Shotcrete
- Tunnel support
- Mining roadways
- Slope protection
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