Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
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Sources8 documents: Isola, National Ready Mixed Concrete Association, Federal Highway Administration, Oak Ridge National Laboratory, USDA Forest Products Laboratory, National Institute of Standards and Technology
Concrete
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
PCB Board FR-4, 2 copper planes
A whole circuit board read as one orthotropic plate: the JEDEC high-K thermal test board (JESD51-7, "2s2p"), 0.062 in (1.575 mm) thick with two internal solid copper planes 0.0014 in (1 oz) thick, as Texas Instruments SZZA017A Table 1 gives it. Copper C110 and the Isola 370HR laminate from this library; the layers conduct in parallel along the board and in series through it (boardStackup.ts). Its two 0.0028 in trace layers cover little of the board and are left out; vias are ignored. Mechanical values are the bare laminate's.
1
370HR Laminate and Prepreg Data SheetIsolaarchived copyPCB Board FR-4, 2 copper planes · Ultimate tensile strength: the bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D3039)PCB Board FR-4, 2 copper planes · Young's modulus (stiffness): the bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D790-15e2); the copper planes are left outPCB Board FR-4, 2 copper planes · Poisson's ratio: the bare laminate's (fr4-370hr), in-plane: cross direction .. length directionPCB Board FR-4, 2 copper planes · Thermal expansion: the bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)
2
CIP 35: Testing Compressive Strength of ConcreteNational Ready Mixed Concrete Associationarchived copyConcrete · Compressive strength: specified compressive strength class (f'c), not a measured typical
CIP 36: Structural Lightweight ConcreteNational Ready Mixed Concrete Associationarchived copyConcrete · Density: range for normalweight concrete
5
The Effect of Elevated Temperature on Concrete Materials and Structures: A Literature Review (ORNL/TM-2005/553)Oak Ridge National Laboratoryarchived copyConcrete · Poisson's ratio: general range at normal ambient conditions (overall 0.11-0.32)Concrete · Max service temperature: code long-term temperature limit (ASME Code, concrete containments)
Thermal Coefficient of Portland Cement ConcreteFederal Highway AdministrationConcrete · Thermal expansion: typical range for portland cement concrete (aggregate dependent)
8
Best Practice Guidelines for Structural Fire Resistance Design of Concrete and Steel Buildings (TN 1681)National Institute of Standards and Technologyarchived copyConcrete · Specific heat: typical (NIST guidance for thermal analysis)
Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Mechanical
Which is stiffer, Concrete or PCB Board FR-4, 2 copper planes?
Concrete is stiffer: Young's modulus 25.1 GPa against 23.9 GPa for PCB Board FR-4, 2 copper planes, so the same part in Concrete deflects less under the same load.
Thermal
Which expands less with temperature?
Concrete expands less: 10 µm/m·K against 13.5 µm/m·K for PCB Board FR-4, 2 copper planes.