Properties

One scheme for every kind of matter, from steel to water, argon or asphalt. Each material shows only the categories it has values for, but the place of every property is fixed before the first value arrives.

Category	Steel	Timber	Concrete	Aluminium
Identity and composition	12	·	·	11
Physical	1	39	gap	2
Mechanical	51	39	1	21
Thermal	1	13	gap	gap
Moisture and transport	·	13	gap	·
Fire	gap	39	gap	gap
Electrical and magnetic	·	·	·	·
Optical	·	·	·	·
Chemical and durability	gap	gap	gap	gap
Design values	9	39	·	18

Number of grades with sourced values in the category. “gap”: the category matters for the material but nothing is sourced yet.

What kind of number

Guaranteed ≥ 355 MPa
A minimum, maximum or range the product standard guarantees (S355).
Characteristic 30 MPa
The 5th percentile a strength class is defined by (C30/37, GL24h).
Nominal 210 000 MPa
A value a design code tells you to use (E, fo, fu,haz).
Reference 998.2 kg/m³
A measured property of a defined substance at a stated state (water at 20 °C, 101.325 kPa).
Typical ≈ 330 MPa
What a producer usually gets. Shown, never used as a design basis.

The state a value holds in

Thickness
Steel and aluminium strength falls with thickness
Temperature
Charpy test temperature; any property of water or argon
Pressure
Gases and fluids: density of argon at 101.325 kPa
Moisture content
Timber at 12 %; concrete wet or dry
Age
Concrete strength at 28 days
Load duration
Timber and plastics: strength and creep depend on how long a load acts
Phase
Solid, liquid or gas: water, ice and steam are one substance

Identity and composition

What the material is: chemical composition, formula, phase at room temperature. Composition limits are shown on the grade page and on the periodic table.

Composition limits for 23 grades, also shown on the periodic table.

Planned Formula and CAS number · Molar mass · Phase at 20 °C and 101.325 kPa

Physical

Mass and volume: density, unit weight, porosity, viscosity of fluids.

Property	Symbol	Unit	Grades with values
Density Mass per unit volume.	ρ	kg/m³	Steel 1Aluminium 2
Unit weight Weight per unit volume, for self-weight loads.	γ	kN/m³	Steel 1
Characteristic density 5th-percentile density.	ρk	kg/m³	Timber 39
Mean density Mean density.	ρmean	kg/m³	Timber 39

Planned Porosity · Dynamic viscosity (water, bitumen) · Bulk density of granular materials

Mechanical

Response to load: stiffness, strength, ductility, toughness and behaviour over time.

Property	Symbol	Unit	Grades with values
Yield strengthStrength Upper yield strength guaranteed by the product standard (minimum).	ReH	MPa	Steel 51Aluminium 21
Tensile strengthStrength Ultimate tensile strength. Product standards give a range or a minimum.	Rm	MPa	Steel 48Aluminium 21
Elongation after fractureDuctility Minimum elongation; depends on gauge length and test direction.	A	%	Steel 39Aluminium 19
Elongation at maximum forceDuctility Total elongation at maximum force (εuk in Eurocode 2): the ductility measure for reinforcement.	Agt	%	Steel 3
Tensile-to-yield ratioDuctility k = (ft/fy)k in Eurocode 2. Higher means more strain hardening after yield.	Rm/Re	—	Steel 4
Yield-to-tensile ratioDuctility Capped in seismic grades (A992: 0.85) so members can yield before they break.	Fy/Fu	—	Steel 1
Impact energy (Charpy V)Toughness Minimum absorbed energy at the stated test temperature.	KV	J	Steel 6
Modulus of elasticityElastic Young's modulus for design.	E	MPa	Steel 1Concrete 1Timber 39Aluminium 2
Shear modulusElastic G = E / 2(1 + ν).	G	MPa	Steel 1Timber 39
Poisson's ratioElastic In the elastic range.	ν	—	Steel 1
Characteristic cylinder strengthStrength 28-day characteristic compressive strength, 150×300 mm cylinder.	fck	MPa	Concrete 1
Characteristic cube strengthStrength 28-day characteristic compressive strength, 150 mm cube.	fck,cube	MPa	Concrete 1
Mean compressive strengthStrength fcm = fck + 8 MPa.	fcm	MPa	Concrete 1
Mean axial tensile strengthStrength fctm = 0.30·fck^(2/3) up to C50/60.	fctm	MPa	Concrete 1
Bending strengthStrength Characteristic bending strength.	fm,k	MPa	Timber 39
Tension parallel to grainStrength Characteristic tensile strength along the grain.	ft,0,k	MPa	Timber 39
Compression parallel to grainStrength Characteristic compressive strength along the grain.	fc,0,k	MPa	Timber 39
Shear strengthStrength Characteristic shear strength.	fv,k	MPa	Timber 39
Tension perpendicular to grainStrength Characteristic tensile strength across the grain; small, so details avoid it.	ft,90,k	MPa	Timber 39
Compression perpendicular to grainStrength Characteristic compressive strength across the grain: governs bearing at supports.	fc,90,k	MPa	Timber 39
Rolling shear strengthStrength Shear in the plane across the grain (fibres rolling over each other).	fr,k	MPa	Timber 13
Modulus of elasticity, 5th percentileElastic Parallel to grain. Used for stability (buckling, lateral torsional buckling).	E0,05	MPa	Timber 39
Modulus of elasticity perpendicular to grainElastic Mean value, for deformations across the grain.	E90,mean	MPa	Timber 39
Modulus perpendicular to grain, 5th percentileElastic Characteristic value across the grain.	E90,05	MPa	Timber 13
Shear modulus, 5th percentileElastic Characteristic shear modulus, for stability checks.	G05	MPa	Timber 13

Planned Bulk modulus K (fluids and solids) · Hardness (HB, HV) · Fracture toughness KIC · Fatigue strength · Creep coefficient (concrete), kdef (timber) · Stiffness modulus of asphalt (EN 12697-26)

Thermal

Heat: expansion, conductivity, heat capacity and the temperatures where the material changes state.

Property	Symbol	Unit	Grades with values
Coefficient of thermal expansion Linear, near room temperature.	α	×10⁻⁶ /K	Steel 1
Thermal conductivity Heat flow through 1 m of material per kelvin of temperature difference.	λ	W/(m·K)	Timber 13

Planned Thermal conductivity λ · Specific heat capacity cp · Melting, boiling and glass transition temperatures · Softening point (bitumen)

Moisture and transport

Water and vapour: what moves through the material and how its properties change with moisture.

Property	Symbol	Unit	Grades with values
Swelling and shrinkage across the grain Change in cross-section dimension per 1 % change in moisture content.	αu,90	% per % moisture	Timber 13

Planned Water vapour resistance factor μ · Water absorption · Permeability

Fire

Reaction to fire, charring and loss of strength at high temperature.

Property	Symbol	Unit	Grades with values
One-dimensional charring rate Charring depth per minute of standard fire exposure on one face.	β0	mm/min	Timber 39
Notional charring rate Includes the effect of corner rounding and fissures; used with the reduced cross-section method.	βn	mm/min	Timber 39

Planned Euroclass (EN 13501-1) · Charring rate β0 (timber) · Reduction factors ky,θ (steel, aluminium) · Flammability limits (gases)

Electrical and magnetic

Conductivity, permittivity, magnetic behaviour.

Planned Electrical resistivity · Relative permittivity · Magnetic permeability

Optical

Light: refraction, transmission, reflection.

Planned Refractive index · Light transmittance · Solar factor g (glass)

Chemical and durability

Corrosion, reactivity and resistance to the environment the material lives in.

Planned Corrosion rate by atmospheric category (ISO 9223) · Exposure classes XC/XD/XS (concrete) · Use class and natural durability (timber)

Design values

Not properties of the material but rules of a design code (Eurocode, AISC, ACI): the strength a code lets you design with, reduced zones next to welds, partial factors. Kept apart so a code's rule is never mistaken for a test result.

Property	Symbol	Unit	Grades with values
Design yield strength Nominal value used in design calculations (before partial factors).	fy	MPa	Steel 9Aluminium 18
Design ultimate strength Nominal ultimate strength used in design calculations.	fu	MPa	Steel 9Aluminium 18
HAZ proof strength 0.2 % proof strength in the heat-affected zone of a weld (Eurocode 9).	fo,haz	MPa	Aluminium 18
HAZ ultimate strength Ultimate strength in the heat-affected zone of a weld (Eurocode 9).	fu,haz	MPa	Aluminium 18
Modification factor for load duration and moisture Multiplies characteristic strength: fd = kmod · fk / γM. Wood is weaker under long-lasting loads and when wet.	kmod	—	Timber 39
Deformation factor (creep) Final deformation = instantaneous × (1 + ψ2 · kdef) for quasi-permanent loads.	kdef	—	Timber 39
Partial factor for the material Recommended value; each country may set its own in the National Annex (a Nationally Determined Parameter).	γM	—	Timber 39

Planned Partial factors γM · Values per National Annex