Compare / C55/67 vs C70/85
C55/67 vs C70/85
EN 1992-1-1:2004 · Concrete
55 MPa cylinder, 67 MPa cube characteristic strength at 28 days; Ecm 38 GPa.
EN 1992-1-1:2004 · Concrete
70 MPa cylinder, 85 MPa cube characteristic strength at 28 days; Ecm 41 GPa.
Mechanical
| Property | Condition | C55/67 | C70/85 | Difference |
|---|---|---|---|---|
| Secant modulus of elasticity Ecm | 28 days | 38 000MPa2 | 41 000MPa2 | +7.9 % |
| Poisson's ratio ν | uncracked | 0.21 | 0.21 | same |
| Characteristic cylinder strength fck | 28 days | 55MPa3 | 70MPa3 | +27 % |
| Characteristic cube strength fck,cube | 28 days | 67MPa3 | 85MPa3 | +27 % |
| Mean compressive strength fcm | 28 days | 63MPa3 | 78MPa3 | +24 % |
| Mean axial tensile strength fctm | 28 days | 4.2MPa2 | 4.6MPa2 | +9.5 % |
| Characteristic tensile strength (5 % fractile) fctk,0.05 | 28 days | 3MPa2 | 3.2MPa2 | +6.7 % |
| Characteristic tensile strength (95 % fractile) fctk,0.95 | 28 days | 5.5MPa2 | 6MPa2 | +9.1 % |
| Strain at peak stress εc1 | — | 2.5‰2 | 2.7‰2 | +8.0 % |
| Ultimate strain (analysis curve) εcu1 | — | 3.2‰2 | 2.8‰2 | −13 % |
| Strain at maximum stress (parabola-rectangle) εc2 | — | 2.2‰2 | 2.4‰2 | +9.1 % |
| Ultimate strain (parabola-rectangle) εcu2 | — | 3.1‰2 | 2.7‰2 | −13 % |
| Exponent of the parabola n | — | 1.752 | 1.452 | −17 % |
| Strain at maximum stress (bilinear) εc3 | — | 1.8‰2 | 2‰2 | +11 % |
| Ultimate strain (bilinear) εcu3 | — | 3.1‰2 | 2.7‰2 | −13 % |
Design values
| Property | Condition | C55/67 | C70/85 | Difference |
|---|---|---|---|---|
| Long-term coefficient on compressive strength αcc | — | 11 | 11 | same |
| Partial factor for the material γc | persistent and transient design situations | 1.51 | 1.51 | same |
Physical
| Property | Condition | C55/67 | C70/85 | Difference |
|---|---|---|---|---|
| Unit weight γ | reinforced, normal percentage of reinforcement | 25kN/m³1 | 25kN/m³1 | same |
Thermal
| Property | Condition | C55/67 | C70/85 | Difference |
|---|---|---|---|---|
| Coefficient of thermal expansion α | — | 10×10⁻⁶ /K1 | 10×10⁻⁶ /K1 | same |
Rows are matched by condition (thickness band, temperature, product form). A dash means the grade has no sourced value for that condition. Differences are C70/85 relative to C55/67; for ranges the lower bound is compared.