Description
QD-Y Post-Tensioning Duct Grouting Material
The QD-Y from QianDao is a premium, factory-prepared grout specifically formulated for the demanding requirements of post-tensioned concrete structures. It is designed to provide a dense, durable, and corrosion-free environment for prestressing steel, ensuring structural integrity and longevity.
Key Features & Benefits
- Superior Fluidity: Designed for excellent pumpability and complete filling of complex ducts, with a controlled initial flow of 10-17 seconds to ensure easy application.
- Zero Bleeding: Guarantees no water separation (0% bleeding at 3 hours and 24 hours), preventing voids and ensuring homogeneous protection against corrosion.
- High & Durable Strength: Delivers outstanding compressive and flexural strength, exceeding 50 MPa and 10 MPa at 28 days respectively, ensuring full load transfer and long-term durability [citation:3].
- Controlled Expansion: Provides slight, controlled free expansion (0-3% at 24 hours) to compensate for shrinkage and ensure intimate contact with the duct wall and steel strands.
- Corrosion Inhibition: Offers proven non-corrosive action on reinforcing steel, protecting the tendons from environmental attack and extending service life.
- Optimized Setting Time: Features a well-balanced setting time, with an initial set of ≥5 hours and a final set of ≤24 hours, suitable for large-scale and complex grouting operations.
Technical Specifications
The QD-Y grout is formulated to meet and exceed the rigorous standards of modern construction, including compliance with JTG/T 3650-2020 [citation:2].
| Test Item | Technical Requirement |
|---|---|
| Water-Binder Ratio (%) | 0.26 – 0.28 |
| Setting Time (h) | Initial: ≥5 |
| Final: ≤24 | |
| Flowability (25°C, s) | Initial: 10 – 17 |
| After 30 min: 10 – 20 | |
| After 60 min: 10 – 25 | |
| Bleeding Rate (%) | 3h (Between Wires): 0 |
| 24h (Free): 0 | |
| Pressure Bleeding Rate (%) | 0.22 MPa: ≤2.0 |
| 0.36 MPa: – | |
| Free Expansion Rate (%) | 3h: 0 – 2 |
| 24h: 0 – 3 | |
| Flexural Strength (MPa) | 3d: ≥5 |
| 7d: ≥6 | |
| 28d: ≥10 | |
| Compressive Strength (MPa) | 3d: ≥20 |
| 7d: ≥40 | |
| 28d: ≥50 | |
| Corrosion Action on Steel | Non-corrosive |
| Filling Capacity | Qualified |
| Air Content (%) | 1 – 3 |
Applications
- Post-Tensioned Concrete: Grouting of prestressing ducts in bridges, viaducts, and box girders.
- Highway & Railway Infrastructure: Suitable for large-scale projects like highways, railways, and high-speed rail [citation:2].
- Special Structures: Nuclear power plants, wind turbine foundations, and other heavy-load or critical structures requiring high-performance grouting [citation:2].
Frequently Asked Questions (FAQs)
1. What standards does the QD-Y grout comply with?
The QD-Y is designed to comply with the JTG/T 3650-2020 ‘Technical Specifications for Construction of Highway Bridge and Culvert’ [citation:2].
2. How does QD-Y prevent corrosion of the steel strands?
By providing a dense, void-free, and stable environment with zero bleeding, QD-Y eliminates water accumulation points that are the primary cause of corrosion. It has also been tested to have a non-corrosive action on steel [citation:2][citation:4].
3. What is the recommended mixing procedure?
While the water-binder ratio is 0.26-0.28, it is crucial to follow a standardized mixing procedure. First, add water to the mixer, then add the QD-Y powder. Mix with a high-shear mixer, typically at a speed of no less than 1000 rpm, for 3-5 minutes until a homogenous paste is achieved [citation:3].
