C20/25 vs C90/105

C90/105 is 1.5 times as stiff as C20/25. Their densities are about the same. Per unit mass C90/105 is 1.5 times as stiff. Strength: f_ck = 20 MPa for C20/25, f_ck = 90 MPa for C90/105.

C20/25 EN 1992-1-1 C90/105 EN 1992-1-1

Side by side

ratio = C90/105 / C20/25 · log scale

Property	C20/25	C90/105	Unit	Ratio
E Young's modulus	30	44	GPa	1.47×
G Shear modulus	12.5	18.33	GPa	1.47×
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	90	MPa	4.5×
f_ck,cube Characteristic cube strength	25	105	MPa	4.2×
f_cm Mean cylinder strength	28	98	MPa	3.5×
f_ctm Mean tensile strength	2.2	5	MPa	2.27×
f_ctk,0.05 Tensile strength, 5 % fractile	1.5	3.5	MPa	2.33×
f_ctk,0.95 Tensile strength, 95 % fractile	2.9	6.6	MPa	2.28×
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	2.6	‰	1.3×
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	2.3	‰	1.31×
ε_cu3 Ultimate strain, bilinear	3.5	2.6	‰	0.743×
E/ρ Specific stiffness E/ρ · derived	12.26	17.98	MJ/kg	1.47×
c₀ Bar wave speed √(E/ρ) · derived	3501	4240	m/s	1.21×
f/ρ Specific strength f/ρ · derived	8.172	36.78	kJ/kg	4.5×

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.