C20 vs C30

C30 is 1.3 times as stiff as C20. It is 1.1 times as dense. Per unit mass C30 is 1.1 times as stiff. Strength: f_m,k = 20 MPa for C20, f_m,k = 30 MPa for C30.

C20 EN 338:2016 C30 EN 338:2016

Side by side

ratio = C30 / C20 · log scale

Property	C20	C30	Unit	Ratio
E₁ Modulus, direction 1	9.5	12	GPa	1.26×
E₂ Modulus, direction 2	0.32	0.4	GPa	1.25×
E₃ Modulus, direction 3	0.32	0.4	GPa	1.25×
G₁₂ Shear modulus 1-2	0.59	0.75	GPa	1.27×
G₁₃ Shear modulus 1-3	0.59	0.75	GPa	1.27×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	6.4	8	GPa	1.25×
ρ Density	400	460	kg/m³	1.15×
ρ_k Density, characteristic (5 % fractile)	330	380	kg/m³	1.15×
f_m,k Bending strength	20	30	MPa	1.5×
f_t,0,k Tension parallel to grain	11.5	19	MPa	1.65×
f_t,90,k Tension perpendicular to grain	0.4	0.4	MPa	1×
f_c,0,k Compression parallel to grain	19	24	MPa	1.26×
f_c,90,k Compression perpendicular to grain	2.3	2.7	MPa	1.17×
f_v,k Shear strength	3.6	4	MPa	1.11×
E/ρ Specific stiffness E/ρ · derived	23.75	26.09	MJ/kg	1.1×
c₀ Bar wave speed √(E/ρ) · derived	4873	5108	m/s	1.05×
f/ρ Specific strength f/ρ · derived	50	65.22	kJ/kg	1.3×

Values at the first thickness band or product form of each material (EN 338:2016; EN 338:2016). A minimum and a characteristic value are not the same kind of number — read the ratio as a guide. Each material's page lists every band and every source.