IMARA BAR · IMC-RB
GFRP Rebar
High-strength reinforcement for durable concrete structures.
System definition
What is GFRP rebar and when is it used?
GFRP Rebar is a high-strength glass fibre reinforced polymer bar for reinforced-concrete structures where durability, corrosion resistance and lower operating costs are critical.
The material combines low weight, high tensile strength and complete resistance to moisture, salts and most aggressive chemical environments, helping structures perform without the risk of corrosion failure.
Technical content owner: IMARA Engineering Centre
- 01Product line
- IMARA BAR
- 02Family code
- IMC-RB
- 03Outside diameter
- 4-30 mm
- 04Surface
- Deformed profile · no sand coating
Technical data
Open the data required for assessment.
The first section is open for immediate reference. Expand further properties, dimensions, supply information and documentation as required.
01Product identity and article codingDeclared IMARA BAR properties, base articles and commercial SKU rules.+
| Parameter | Declared technical data |
|---|---|
| Commercial line | IMARA BAR |
| Family code | IMC-RB |
| Official product name | IMARA Composites GFRP Rebar Without Sand Coating |
| Material | Four-component epoxy-based compound with continuous glass roving |
| Surface | Deformed / periodic profile; no sand coating |
| Outer and core diameter tolerance | ±0.5 mm |
| Tensile strength, OD 4-13 mm | ≥1,000 MPa |
| Tensile strength, OD 14-30 mm | ≥800 MPa |
| Tensile modulus, OD 4-13 mm | ≥50,000 MPa |
| Tensile modulus, OD 14-30 mm | ≥45,000 MPa |
| Compressive strength | ≥300 MPa |
| Straight-bar length | Up to 12 linear metres |
| Coil option | 50 linear metres for selected diameters up to OD 12 mm |
| Engineering product reference | ASTM D7957/D7957M-22 |
| Structural design reference | ACI 440.11-22 |
| Outer diameter | Core diameter | Base article |
|---|---|---|
| 4.0 mm | 3.0 mm | IMC-RB-OD040-CD030 |
| 5.0 mm | 4.0 mm | IMC-RB-OD050-CD040 |
| 5.5 mm | 4.5 mm | IMC-RB-OD055-CD045 |
| 6.0 mm | 5.0 mm | IMC-RB-OD060-CD050 |
| 7.0 mm | 6.0 mm | IMC-RB-OD070-CD060 |
| 8.0 mm | 7.0 mm | IMC-RB-OD080-CD070 |
| 9.0 mm | 8.0 mm | IMC-RB-OD090-CD080 |
| 10.0 mm | 9.0 mm | IMC-RB-OD100-CD090 |
| 12.0 mm | 10.5 mm | IMC-RB-OD120-CD105 |
| 14.0 mm | 12.5 mm | IMC-RB-OD140-CD125 |
| 16.0 mm | 14.5 mm | IMC-RB-OD160-CD145 |
| 18.0 mm | 16.5 mm | IMC-RB-OD180-CD165 |
| 20.0 mm | 18.5 mm | IMC-RB-OD200-CD185 |
| 22.0 mm | 20.5 mm | IMC-RB-OD220-CD205 |
| 24.0 mm | 23.5 mm | IMC-RB-OD240-CD235 |
| 26.0 mm | 24.5 mm | IMC-RB-OD260-CD245 |
| 28.0 mm | 26.5 mm | IMC-RB-OD280-CD265 |
| 30.0 mm | 28.5 mm | IMC-RB-OD300-CD285 |
| Code | Meaning | Example |
|---|---|---|
| ST | Straight bar | IMC-RB-OD080-CD070-ST-L12000 |
| CL | Coil | IMC-RB-OD080-CD070-CL-L50000 |
| Lxxxxx | Supplied length in millimetres | L12000 = 12 m; L50000 = 50 m |
02Physical and mechanical performanceReference properties for early-stage material assessment.+
| Characteristic | Reference steel rebar | IMARA GFRP |
|---|---|---|
| Material | Steel | E-glass fibre with epoxy resin, hardener and accelerating agent |
| Declared tensile strength | 390 MPa | ≥1,000 MPa (OD 4-13 mm); ≥800 MPa (OD 14-30 mm) |
| Elongation | 1.4% | 2.3% |
| Thermal conductivity | 46 W/(m·°C) | 0.35 W/(m·°C) |
| Tensile modulus | 200,000 MPa | ≥50,000 MPa (OD 4-13 mm); ≥45,000 MPa (OD 14-30 mm) |
| Linear expansion coefficient | 13-15 ×10⁻⁶/°C | 9-12 ×10⁻⁶/°C |
| Density | 7.8 t/m³ | 1.9 t/m³ |
| Length | 6-12 m rods | To project specification |
| Design service life | According to building codes | At least 80 years |
| Operating temperature | -40 to +350°C | -50 to +60°C |
| Maximum compressive strength | 350 MPa | 300 MPa |
03Equivalent replacementReference steel-to-GFRP diameter and mass relationships.+
| Steel Ø | Steel kg/m | GFRP kg/m | GFRP Ø |
|---|---|---|---|
| 6 mm | 0.222 | 0.030 | 5 mm |
| 8 mm | 0.395 | 0.051 | 6 mm |
| 10 mm | 0.617 | 0.066 | 7 mm |
| 12 mm | 0.888 | 0.084 | 8 mm |
| 14 mm | 1.210 | 0.137 | 10 mm |
| 16 mm | 1.580 | 0.137 | 11 mm |
| 18 mm | 2.000 | 0.202 | 12 mm |
| 20 mm | 2.470 | 0.256 | 14 mm |
04Design behaviour and limitationsConditions that prevent direct one-to-one substitution for steel.+
- GFRP is an independent engineering material and is not selected by direct one-to-one substitution for steel.
- The material behaves linearly to rupture and has no steel-like yield plateau or plastic redistribution stage.
- Deflection, crack width, bar spacing and sustained stress can govern selection before tensile capacity.
- Flexure, shear, punching, anchorage and connections require separate project checks.
- The reduced strength of bent portions is considered wherever GFRP stirrups or bent elements are used.
- All bent reinforcement is factory-made; bending GFRP bars on site is not permitted.
- Fire, elevated temperature, seismic action, fatigue, freezing and impact require project-specific verification.
05Surface and bond profileThe declared IMARA BAR product has a deformed periodic profile without sand coating.+
- Declared surface
- Deformed / periodic profile without sand coating
- Bond verification
- Bond performance is verified for the supplied profile and selected diameter
- Tolerance
- Outer and core diameter tolerance ±0.5 mm
06Supply, handling and installationFormats and procedures that affect specification and site work.+
- Outer diameters 4-30 mm are available as straight bars up to 12 linear metres.
- Selected diameters up to OD 12 mm can be supplied in 50 m coils.
- Store horizontally and protect from long-term ultraviolet exposure.
- Cut with an angle grinder and join using tie wire or plastic fasteners.
- Large coils are unwound vertically by at least two people near the work area.
07Quality verification and selectionReference thresholds, batch documentation and project review sequence.+
- Quality-management certification for the supplying manufacturer must be current and verified for the project.
- The verification package should identify nominal and measured cross-sectional area, guaranteed tensile strength, modulus, strain, bond and transverse strength.
- Alkaline-resistance, moisture-absorption, cure, transition-temperature and fibre-content records are checked for the selected product.
- Every commercial batch requires an identifiable batch number, quality-control report and traceable supply documentation.
| Parameter | Technical reference value |
|---|---|
| Glass-fibre content by mass | Not less than 70% |
| Glass-transition temperature | Not less than 100°C |
| Degree of cure | Not less than 95% |
| Average tensile modulus | Not less than 44,800 MPa |
| Average ultimate strain | Not less than 1.1% |
| Moisture absorption to saturation | Not more than 1.0% |
| 24-hour moisture absorption | Not more than 0.25% |
| Strength retention after alkaline exposure | Not less than 80% |
| Strength of bent portion | Not less than 60% of straight-bar value |
| Transverse shear strength | Not less than 131 MPa |
| Bond strength | Not less than 7.6 MPa |
| Stage | Scope of verification |
|---|---|
| 01 · Service conditions | Exposure, moisture, chemicals, temperature, fire and seismic action |
| 02 · Structural function | Longitudinal, distribution, temperature-shrinkage or shear reinforcement |
| 03 · Material properties | Guaranteed strength, modulus, strain, area, bond and bent-element properties |
| 04 · Ultimate limit state | Flexure, tension, compression zone, shear, punching, anchorage and connections |
| 05 · Serviceability | Deflection, crack width, bar spacing and long-term deformation |
| 06 · Special effects | Temperature, fire, seismic action, fatigue, chemicals, freezing and impact |
| 07 · Design specification | Type, diameter, cover, anchorage, installation and batch control |
Reference values support early-stage selection. Final diameter replacement, detailing and compliance must be verified for the governing code, load case and project environment.
Project context
Applications and benefits are supporting information.
Use these references to identify a potential material system, then confirm suitability through engineering verification.
Open supporting informationApplications & engineering benefits+
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Engineering verification
Submit project parameters and drawings.
IMARA will review the structural function, environment, governing requirements, supply format and interfaces with adjacent systems.