C20/25 vs C80/95

C80/95 is 1.4 times as stiff as C20/25. Their densities are about the same. Per unit mass C80/95 is 1.4 times as stiff. Strength: f_ck = 20 MPa for C20/25, f_ck = 80 MPa for C80/95.

C20/25 EN 1992-1-1 C80/95 EN 1992-1-1

Side by side

ratio = C80/95 / C20/25 · log scale

Property	C20/25	C80/95	Unit	Ratio
E Young's modulus	30	42	GPa	1.4×
G Shear modulus	12.5	17.5	GPa	1.4×
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	20	80	MPa	4×
f_ck,cube Characteristic cube strength	25	95	MPa	3.8×
f_cm Mean cylinder strength	28	88	MPa	3.14×
f_ctm Mean tensile strength	2.2	4.8	MPa	2.18×
f_ctk,0.05 Tensile strength, 5 % fractile	1.5	3.4	MPa	2.27×
f_ctk,0.95 Tensile strength, 95 % fractile	2.9	6.3	MPa	2.17×
ε_c1 Strain at peak stress	2	2.8	‰	1.4×
ε_cu1 Ultimate strain	3.5	2.8	‰	0.8×
ε_c2 Strain at peak, parabola–rectangle	2	2.5	‰	1.25×
ε_cu2 Ultimate strain, parabola–rectangle	3.5	2.6	‰	0.743×
n Exponent, parabola–rectangle	2	1.4	–	0.7×
ε_c3 Strain at peak, bilinear	1.75	2.2	‰	1.26×
ε_cu3 Ultimate strain, bilinear	3.5	2.6	‰	0.743×
E/ρ Specific stiffness E/ρ · derived	12.26	17.16	MJ/kg	1.4×
c₀ Bar wave speed √(E/ρ) · derived	3501	4143	m/s	1.18×
f/ρ Specific strength f/ρ · derived	8.172	32.69	kJ/kg	4×

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.