C14 vs C40

C40 is about twice as stiff as C14. It is 1.4 times as dense. Per unit mass C40 is 1.5 times as stiff. Strength: f_m,k = 14 MPa for C14, f_m,k = 40 MPa for C40.

C14 EN 338:2016 C40 EN 338:2016

Side by side

ratio = C40 / C14 · log scale

Property	C14	C40	Unit	Ratio
E₁ Modulus, direction 1	7	14	GPa	2×
E₂ Modulus, direction 2	0.23	0.47	GPa	2.04×
E₃ Modulus, direction 3	0.23	0.47	GPa	2.04×
G₁₂ Shear modulus 1-2	0.44	0.88	GPa	2×
G₁₃ Shear modulus 1-3	0.44	0.88	GPa	2×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	4.7	9.4	GPa	2×
ρ Density	350	480	kg/m³	1.37×
ρ_k Density, characteristic (5 % fractile)	290	400	kg/m³	1.38×
f_m,k Bending strength	14	40	MPa	2.86×
f_t,0,k Tension parallel to grain	7.2	26	MPa	3.61×
f_t,90,k Tension perpendicular to grain	0.4	0.4	MPa	1×
f_c,0,k Compression parallel to grain	16	27	MPa	1.69×
f_c,90,k Compression perpendicular to grain	2	2.8	MPa	1.4×
f_v,k Shear strength	3	4	MPa	1.33×
E/ρ Specific stiffness E/ρ · derived	20	29.17	MJ/kg	1.46×
c₀ Bar wave speed √(E/ρ) · derived	4472	5401	m/s	1.21×
f/ρ Specific strength f/ρ · derived	40	83.33	kJ/kg	2.08×

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.