7.1. Material characteristics

This paragraph contains tables containing the different material properties of the defined concrete introduction strength classes 1.

Strenght and stiffness

Table 7.1 Properties of concrete classes.

Material Property	C12/15	C20/25	C30/37	C35/45	C45/55	C50/60
Density \(ρ_{rep}\) (kg/m³)	2500	2500	2500	2500	2500	2500
Modulus of Elasticity (uncracked) \(E_{cm}\) (N/mm²)	27000	30000	33000	34000	36000	37000
Mean Compressive Strength \(f_{cm}\) (N/mm²)	20	28	38	43	53	58
Characteristic Cylinder Strength \(f_{ck}\) (N/mm²)	12	20	30	35	45	50
Characteristic Cube Strength \(f_{ck;cube}\) (N/mm²)	15	25	37	45	55	60
Mean Value Tensile Strength \(f_{ctm}\) (N/mm²)	1.6	2.2	2.9	3.2	3.8	4.1
Characteristic Tensile Strength \(f_{ctk;0,05}\) (N/mm²)	1.1	1.5	2.0	2.2	2.7	2.9

Strength

Design compressive strength: \( \frac{f_{ck}}{\gamma} = \frac{f_{ck}}{1.5} \)

Design shear strength: \( b \cdot d \cdot 0.035 \cdot k^{\frac{3}{2}} \cdot \sqrt{f_{ck}} \) (lower bound, for exact value, see EC2). Shear resistance can be increased using shear reinforcement.

\( k = 1 + \sqrt{\frac{200}{d}} \leq 2 \); d in mm

Stress-strain diagram

• \(σ_{c}\) : concrete compressive stress

• \(ε_c\) : concrete compressive strain

• \(f_{cd}\) : design compressive strength

• \(ε_{c3}\) : strain at the start of plastic deformation

• \(ε’_{bu}\) : limit strain

• \(ε_{c3}\) : 1,75 ‰

• \(ε_{cu3}\) : 3,50 ‰

Note

This diagram changes when higher strength classes are chosen. For the strength classes shown in the table in this paragraph these values are valid.

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