C45/55 vs C55/67

C55/67 and C45/55 are about equally stiff. Their densities are about the same. Per unit mass they are about equally stiff (14.71 and 15.53 MJ/kg). Strength: f_ck = 45 MPa for C45/55, f_ck = 55 MPa for C55/67.

C45/55 EN 1992-1-1 C55/67 EN 1992-1-1

Side by side

ratio = C55/67 / C45/55 · log scale

Property	C45/55	C55/67	Unit	Ratio
E Young's modulus	36	38	GPa	1.06×
G Shear modulus	15	15.83	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	45	55	MPa	1.22×
f_ck,cube Characteristic cube strength	55	67	MPa	1.22×
f_cm Mean cylinder strength	53	63	MPa	1.19×
f_ctm Mean tensile strength	3.8	4.2	MPa	1.11×
f_ctk,0.05 Tensile strength, 5 % fractile	2.7	3	MPa	1.11×
f_ctk,0.95 Tensile strength, 95 % fractile	4.9	5.5	MPa	1.12×
ε_c1 Strain at peak stress	2.4	2.5	‰	1.04×
ε_cu1 Ultimate strain	3.5	3.2	‰	0.914×
ε_c2 Strain at peak, parabola–rectangle	2	2.2	‰	1.1×
ε_cu2 Ultimate strain, parabola–rectangle	3.5	3.1	‰	0.886×
n Exponent, parabola–rectangle	2	1.75	–	0.875×
ε_c3 Strain at peak, bilinear	1.75	1.8	‰	1.03×
ε_cu3 Ultimate strain, bilinear	3.5	3.1	‰	0.886×
E/ρ Specific stiffness E/ρ · derived	14.71	15.53	MJ/kg	1.06×
c₀ Bar wave speed √(E/ρ) · derived	3835	3940	m/s	1.03×
f/ρ Specific strength f/ρ · derived	18.39	22.47	kJ/kg	1.22×

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.