8–12µm/m·Ksourcetypical range for portland cement concrete (aggregate dependent)
12µm/m·Ksourcenominal (constructional data, no temperature range stated)
100 mm part over a 50 °C swing
50µm growth20% less
60µm growth
Specific heat
900J/kg·Ksourcetypical (NIST guidance for thermal analysis)
460–480J/kg·Ksourcebase material: EN S275JR unalloyed structural steel (the EN counterpart of A36), typical, 50/100 °C
Heats up and cools (diffusivity)
0.431mm²/s
13mm²/s30.2x faster
Thermal shock resistance
not sourced
5,390W/m
Max service temperature
65°Csourcecode long-term temperature limit (ASME Code, concrete containments)
not sourced
Values for
Normal-weight portland cement concrete, strength class f'c = 4000 psi (28 MPa) per NRMCA CIP 35; density NRMCA CIP 36; thermal conductivity USDA FPL Wood Handbook; service temperature ORNL/NRC review
Generic structural steel, cited as ASTM A992 (the current US structural grade): ASTM A992 W-shapes; Fy/Fu specified minimums from AISC publications (AISC 360-16 Commentary; Modern Steel Construction); elastic constants AISC 360; physical constants from the bauforumstahl structural-steel EPD, which names A992 among covered product standards.
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Which is lighter, Concrete or Steel?
Concrete is lighter: 2,320 kg/m³ against 7,850 kg/m³ for Steel.
Which conducts heat better, Concrete or Steel?
Steel conducts heat better: 48 W/m·K against 0.9 W/m·K for Concrete.
Which expands less with temperature?
Concrete expands less: 10 µm/m·K against 12 µm/m·K for Steel.