C40/50 vs C50/60

C50/60 and C40/50 are about equally stiff. Their densities are about the same. Per unit mass they are about equally stiff (14.3 and 15.12 MJ/kg). Strength: f_ck = 40 MPa for C40/50, f_ck = 50 MPa for C50/60.

C40/50 EN 1992-1-1 C50/60 EN 1992-1-1

Side by side

ratio = C50/60 / C40/50 · log scale

Property	C40/50	C50/60	Unit	Ratio
E Young's modulus	35	37	GPa	1.06×
G Shear modulus	14.58	15.42	GPa	1.06×
ν Poisson's ratio	0.2	0.2	–	1×
ρ Density	2447	2447	kg/m³	1×
γ Weight density	24	24	kN/m³	1×
α Coefficient of thermal expansion	10	10	10⁻⁶/K	1×
f_ck Characteristic cylinder strength	40	50	MPa	1.25×
f_ck,cube Characteristic cube strength	50	60	MPa	1.2×
f_cm Mean cylinder strength	48	58	MPa	1.21×
f_ctm Mean tensile strength	3.5	4.1	MPa	1.17×
f_ctk,0.05 Tensile strength, 5 % fractile	2.5	2.9	MPa	1.16×
f_ctk,0.95 Tensile strength, 95 % fractile	4.6	5.3	MPa	1.15×
ε_c1 Strain at peak stress	2.3	2.45	‰	1.07×
ε_cu1 Ultimate strain	3.5	3.5	‰	1×
ε_c2 Strain at peak, parabola–rectangle	2	2	‰	1×
ε_cu2 Ultimate strain, parabola–rectangle	3.5	3.5	‰	1×
n Exponent, parabola–rectangle	2	2	–	1×
ε_c3 Strain at peak, bilinear	1.75	1.75	‰	1×
ε_cu3 Ultimate strain, bilinear	3.5	3.5	‰	1×
E/ρ Specific stiffness E/ρ · derived	14.3	15.12	MJ/kg	1.06×
c₀ Bar wave speed √(E/ρ) · derived	3782	3888	m/s	1.03×
f/ρ Specific strength f/ρ · derived	16.34	20.43	kJ/kg	1.25×

Values at the first thickness band or product form of each material (EN 1992-1-1; EN 1992-1-1). 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.