Product Facts
- Product Name
- Conbextra CB-C - High Flow Dual Shrinkage Compensated Cable Bolting Grout
- Price
- Available
- Availability
- In Stock
- Condition
- New
- Category
- Construction Materials > Grouting & Bonding Products
- Seller
- Fosroc Workspace
- MPN
- FC501088-20KG
Conbextra CB-C - High Flow Dual Shrinkage Compensated Cable Bolting Grout
Conbextra CB-C is a Class A / Class C, dual shrinkage compensated, highly flowable and high strength grout. It can be used for various void fill applications including backfilling behind concrete tunnel segments, bottom up cable bolt grouting applications and general civil applications. Features high strength development allowing early tensioning of cables, dual expansion system compensating for shrinkage in both plastic and hardened states, hydrogen free gaseous expansion, and excellent pumpability over both flowable and thixotropic consistencies.
Conbextra CB-C is a Class A / Class C, dual shrinkage compensated, highly flowable and high strength grout. It can be used for various void fill applications including backfilling behind concrete tunnel segments, bottom up cable bolt grouting applications and general civil applications. Features high strength development allowing early tensioning of cables, dual expansion system compensating for shrinkage in both plastic and hardened states, hydrogen free gaseous expansion, and excellent pumpability over both flowable and thixotropic consistencies.
Price: Available
Brand: Fosroc
Product Data (OpenAI Spec)
View Full JSON Spec ↗Specifications
| Condition | new |
|---|---|
| Category | Construction Materials > Grouting & Bonding Products |
Product Intelligence
Conbextra CB-C: Technical Specifications and Features
Product Description
Conbextra CB-C is a highly flowable, high-strength, dual shrinkage compensated cable bolting grout supplied as a ready-to-use dry powder. The product is manufactured and supplied by Fosroc and is specifically engineered for void fill applications, with primary uses in cable bolt grouting and concrete tunnel segment backfilling.
The grout is classified as both Class A and Class C, featuring dual expansion characteristics that compensate for shrinkage in both the plastic and hardened states. This formulation requires the addition of controlled amounts of clean water and mechanical mixing in a high-shear mixer to achieve the desired consistency.
Key Advantages
Conbextra CB-C offers several significant benefits for specialized grouting applications:
- High Strength Development: Enables early tensioning of cables without relying on harmful chlorides
- Dual Shrinkage Compensation: Dual expansion system (Class A/C) compensates for shrinkage in both plastic and hardened states, conforming to ASTM C1107:2020 non-shrink standards
- Hydrogen-Free Expansion: Uses a gaseous expansion system free from hydrogen
- Excellent Pumpability: Maintains superior flow characteristics across both flowable and thixotropic consistencies
- RCS Hazard Free: Contains less than 0.1% respirable crystalline silica, classified as hazardous-free
- Chloride-Free Formula: Develops early high strength without the use of chlorides
Supply and Packaging
Conbextra CB-C is supplied in 20kg moisture-resistant plastic bags designed to protect the product during storage and transportation. The product code for the 20kg bags is FC501088-20KG.
The product has a shelf life of 36 months from the date of manufacture when stored in original, unopened bags under appropriate conditions, ensuring extended usability for construction and engineering projects.
Technical Properties
Compressive Strength
Laboratory testing conducted at 23°C demonstrates the following compressive strength development:
| Water Addition | 1 Day (MPa) | 7 Days (MPa) | 28 Days (MPa) |
|---|---|---|---|
| 5.1L per 20kg bag | 50 | 75 | 100 |
| 5.8L per 20kg bag | 30 | 65 | 85 |
| 6.3L per 20kg bag | 25 | 55 | 75 |
Additional Properties
- Fresh Wet Density: 2020 kg/m³
- Setting Time: Initial 3 hours; Final 5 hours
- Pumping Life: 120 minutes
- Flow Characteristics: 550mm (Flow Trough); Flowable consistency
- Expansion Characteristics: Up to 2% expansion overcomes plastic settlement; conforms to expansion in hardened state for drying shrinkage
- Cement Type: GP Cement (no aggregates) per AS3972
Mixing Requirements
A forced-action mixer is essential for proper preparation. The recommended mixing procedure includes:
- Mixing Duration: 3 to 5 minutes at slow speed (400-500 rpm)
- Equipment: Suitable mixer with 120/140mm helical mixing paddle fitted to heavy-duty 1600W mixer
- Large Quantities: Require a high shear vane mixer
- Mixing Method: Fill mixer with required water, start mixer, then slowly add powder continuously for 3-5 minutes until lump-free
Water Requirements
| Consistency Type | Water Addition (litres/20kg bag) |
|---|---|
| Thixotropic | 5.1 - 5.8 |
| Flowable | 5.8 - 6.3 |
Application Instructions
Preparation Phase
- Ensure voids are clean and free from debris
- Install cable with care to prevent kinking the breather tube
- Position and secure the grout tube at the bottom of the void
- Flush water through grouting lines and up the void to provide lubrication and prevent water absorption into strata
Placing Process
Continuous grout flow is essential during placement to ensure complete filling. The application process includes:
- Maintain continuous grout flow throughout placement
- Ensure sufficient grout is available to completely fill the void
- Stop pumping when air ceases to bubble out of the breather tube
- Fold and tie off the grout tube after placing to prevent seepage
Cable Installation Considerations
- The breather tube must not be kinked during installation
- Cables are tensioned after grouting to achieve structural bonding
- The product's early high strength development enables rapid cable tensioning
Standards Compliance
Conbextra CB-C conforms to multiple international standards:
- ASTM C1107:2020: Non-shrink grout specification
- AS 1478.2:2005: Australian standard for compressive strength testing at 23°C
Yield Calculation
At the recommended consistency, each 20kg bag yields approximately 12 to 13 litres of mixed material, facilitating efficient project planning and material estimation.
References
- [1] Fosroc_Conbextra_CB-C_TDS.pdf
- [2] Fosroc_Conbextra_CB_TDS.pdf
- [3] Fosroc_Conbextra_HF_TDS.pdf
- [4] Fosroc_Conbextra_HS_TDS.pdf
- [5] Fosroc_Conbextra_C_TDS.pdf