Anti-Washout Admixture (Underwater Concrete)
Anti-Washout Admixture (AWA) is a viscosity-modifying admixture based on cellulose ether or polysaccharide polymer designed for underwater concrete and tremie placement without contact with air. It increases the plastic viscosity and cohesiveness of the fresh concrete mix, preventing cement and aggregate washout when the concrete flows through water, while still maintaining workability for self-compacting or pumped placement. Dosage is typically 0.3–0.8% by weight of cement.
Technical Specifications
| Appearance | White to off-white powder or viscous liquid |
| pH (1% solution) | 6.0–9.0 |
| Recommended Dosage | 0.3–0.8% bwc |
| Active Polymer Content | ≥88% (powder grade) |
| Washout Loss (JCI standard) | ≤1.5% at 0.5% dosage |
Applications
- Tremie concrete placement for bridge pier foundations
- Underwater concrete for marine structures and quay walls
- Bored pile and diaphragm wall concreting below groundwater
- Underwater concrete repair of dam and harbor structures
- Grouting operations in submerged or water-saturated conditions
Key Features
- Anti-Washout Admixture prevents cement washout during underwater free-fall and tremie placement
- Maintains concrete cohesion and self-compacting flow without segregation in water
- Compatible with PCE superplasticizers for low water-cement ratio underwater concrete
- Cellulose ether base meets environmental requirements for marine construction