C20 vs C35

C35 is 1.4 times as stiff as C20. It is 1.2 times as dense. Per unit mass C35 is 1.2 times as stiff. Strength: f_m,k = 20 MPa for C20, f_m,k = 35 MPa for C35.

C20 EN 338:2016 C35 EN 338:2016

Side by side

ratio = C35 / C20 · log scale

Property	C20	C35	Unit	Ratio
E₁ Modulus, direction 1	9.5	13	GPa	1.37×
E₂ Modulus, direction 2	0.32	0.43	GPa	1.34×
E₃ Modulus, direction 3	0.32	0.43	GPa	1.34×
G₁₂ Shear modulus 1-2	0.59	0.81	GPa	1.37×
G₁₃ Shear modulus 1-3	0.59	0.81	GPa	1.37×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	6.4	8.7	GPa	1.36×
ρ Density	400	470	kg/m³	1.18×
ρ_k Density, characteristic (5 % fractile)	330	390	kg/m³	1.18×
f_m,k Bending strength	20	35	MPa	1.75×
f_t,0,k Tension parallel to grain	11.5	22.5	MPa	1.96×
f_t,90,k Tension perpendicular to grain	0.4	0.4	MPa	1×
f_c,0,k Compression parallel to grain	19	25	MPa	1.32×
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	27.66	MJ/kg	1.16×
c₀ Bar wave speed √(E/ρ) · derived	4873	5259	m/s	1.08×
f/ρ Specific strength f/ρ · derived	50	74.47	kJ/kg	1.49×

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.