C12/15
12 MPa cylinder, 15 MPa cube characteristic strength at 28 days; Ecm 27 GPa.
- Characteristic cylinder strength fck
- 12 MPa3characteristic · 28 days
- Characteristic cube strength fck,cube
- 15 MPa3characteristic · 28 days
- Mean axial tensile strength fctm
- 1.6 MPa2nominal · 28 days
- Secant modulus of elasticity Ecm
- 27 000 MPa2nominal · 28 days
- Unit weight γ
- 25 kN/m³1nominal · reinforced, normal percentage of reinforcement
How we know these values · 45 values from 4 sources
- From the standard
- 26
- Confirmed
- 3
- Corroborated
- 11
- Single source
- 5
- Click any value under “All values” to see the sources that state it, with dates.
- How we rate evidence
All values
- Mechanical 15
- Design values 2
- Physical 1
- Thermal 1
- Moisture and transport not yet
- Fire 26
- Chemical and durability not yet
Mechanical
Elastic
Secant modulus of elasticity Ecm
Mean value at 28 days, quartzite aggregates.
| Condition | Value | Evidence |
|---|---|---|
| 27 000MPa | Corroborated |
Poisson's ratio ν
In the elastic range.
| Condition | Value | Evidence |
|---|---|---|
| 0.2 | Single source |
Strength
Characteristic cylinder strength fck
28-day characteristic compressive strength, 150×300 mm cylinder.
| Condition | Value | Evidence |
|---|---|---|
| 12MPacharacteristic | Confirmed |
Characteristic cube strength fck,cube
28-day characteristic compressive strength, 150 mm cube.
| Condition | Value | Evidence |
|---|---|---|
| 15MPacharacteristic | Confirmed |
Mean compressive strength fcm
fcm = fck + 8 MPa.
| Condition | Value | Evidence |
|---|---|---|
| 20MPa | Confirmed |
Mean axial tensile strength fctm
fctm = 0.30·fck^(2/3) up to C50/60.
| Condition | Value | Evidence |
|---|---|---|
| 1.6MPa | Corroborated |
Characteristic tensile strength (5 % fractile) fctk,0.05
Lower characteristic axial tensile strength: for anchorage, shear and design tensile strength.
| Condition | Value | Evidence |
|---|---|---|
| 1.1MPacharacteristic | Corroborated |
Characteristic tensile strength (95 % fractile) fctk,0.95
Upper characteristic tensile strength: where high tensile strength is unfavourable (minimum reinforcement, cracking).
| Condition | Value | Evidence |
|---|---|---|
| 2MPacharacteristic | Corroborated |
Ductility
Strain at peak stress εc1
Nonlinear stress–strain curve for structural analysis (Fig. 3.2).
| Condition | Value | Evidence |
|---|---|---|
| 1.8‰ | Corroborated |
Ultimate strain (analysis curve) εcu1
End of the nonlinear analysis curve.
| Condition | Value | Evidence |
|---|---|---|
| 3.5‰ | Corroborated |
Strain at maximum stress (parabola-rectangle) εc2
Section design, Fig. 3.3.
| Condition | Value | Evidence |
|---|---|---|
| 2‰ | Corroborated |
Ultimate strain (parabola-rectangle) εcu2
Crushing strain used in section design.
| Condition | Value | Evidence |
|---|---|---|
| 3.5‰ | Corroborated |
Exponent of the parabola n
Shape of the parabola-rectangle diagram (Expression 3.17).
| Condition | Value | Evidence |
|---|---|---|
| 2 | Corroborated |
Strain at maximum stress (bilinear) εc3
Bilinear stress–strain relation, Fig. 3.4.
| Condition | Value | Evidence |
|---|---|---|
| 1.75‰ | Corroborated |
Ultimate strain (bilinear) εcu3
Crushing strain of the bilinear relation.
| Condition | Value | Evidence |
|---|---|---|
| 3.5‰ | Corroborated |
Design values
Long-term coefficient on compressive strength αcc
Accounts for long-term effects and the way load is applied: fcd = αcc·fck/γc.
| Condition | Value | Evidence |
|---|---|---|
| 1 | Single source |
Partial factor for the material γc
Recommended value; each country may set its own in the National Annex (a Nationally Determined Parameter).
| Condition | Value | Evidence |
|---|---|---|
| 1.5 | Single source |
Physical
Unit weight γ
Weight per unit volume, for self-weight loads.
| Condition | Value | Evidence |
|---|---|---|
| 25kN/m³ | Single source |
Thermal
Coefficient of thermal expansion α
Linear, near room temperature.
| Condition | Value | Evidence |
|---|---|---|
| 10×10⁻⁶ /K | Single source |
Fire
Compressive strength reduction in fire kc(θ)
fc,θ / fck for normal weight concrete; depends on the aggregate.
| Condition | Value | Evidence |
|---|---|---|
| 1 | From the standard | |
| 1 | From the standard | |
| 0.95 | From the standard | |
| 0.85 | From the standard | |
| 0.75 | From the standard | |
| 0.6 | From the standard | |
| 0.45 | From the standard | |
| 0.3 | From the standard | |
| 0.15 | From the standard | |
| 0.08 | From the standard | |
| 0.04 | From the standard | |
| 0.01 | From the standard | |
| 0 | From the standard | |
| 1 | From the standard | |
| 1 | From the standard | |
| 0.97 | From the standard | |
| 0.91 | From the standard | |
| 0.85 | From the standard | |
| 0.74 | From the standard | |
| 0.6 | From the standard | |
| 0.43 | From the standard | |
| 0.27 | From the standard | |
| 0.15 | From the standard | |
| 0.06 | From the standard | |
| 0.02 | From the standard | |
| 0 | From the standard |
Compare side by side
With any other gradeSources here are public pages that reproduce EN 1992-1-1:2004. For design and acceptance, the standard edition named in your specification and the conformity evaluation of the delivered concrete (EN 206) take precedence. Design factors are recommended values; your National Annex may set others.