Concrete Shrinkage-Reducing Admixture (SRA)
Lowers the surface tension of the pore solution to reduce capillary shrinkage stress, significantly cutting drying and autogenous shrinkage, plastic cracking and later-age cracking.
Overview
Shrinkage cracking is one of the main threats to durability. An SRA reduces the surface tension of the capillary pore solution, lowering the shrinkage stress generated as water is lost — it suppresses the mechanism rather than simply compensating for it.
Key benefits
- Over 30% reduction in 28 d drying shrinkage, markedly fewer shrinkage cracks
- Clear suppression of autogenous shrinkage in low w/b high-strength concrete
- Good compatibility with PCE superplasticizers and air entrainers
- No effect on setting time; strength impact is controlled
Application notes
Add together with the superplasticizer; dosage varies with binder content and strength class. An SRA does not replace curing — maintain proper moist curing. Verify compatibility when combining with expansive agents.
Typical uses
Bridge deck overlays, industrial floors, basement walls, tanks and tunnel linings, high-strength structures.
Technical specification
| Appearance | Colourless to pale yellow liquid |
| Solid content | ≥ 40% |
| 28 d drying shrinkage reduction | ≥ 30% |
| Autogenous shrinkage reduction | ≥ 25% |
| pH value | 7.0 – 9.0 |
| Chloride content | ≤ 0.01% |
| 28 d compressive strength ratio | ≥ 95% |
| Compatibility with superplasticizers | Good |
Standards
Applications
- Bridge deck overlays
- Industrial floors
- Underground structures
- Tank structures
Related products
Concrete Accelerator (Shotcrete Set Accelerator)
Initial set < 5 min · Low rebound · Alkali-free option
Concrete Air-Entraining Admixture
Stable micro-air system · Freeze-thaw resistance