# Properties of normal strength Portland cement concrete

Articles > Properties of normal strength Portland cement concrete

Typical properties of normal strength Portland cement concrete:

• Density : 2240 - 2400 kg/m3 (140 - 150 lb/ft3
• Compressive strength : 20 - 40 MPa (3000 - 6000 psi = 432 - 864 ksf)

Compressive strength of concrete (% of 28-day strength) vs age (days)

• Flexural strength : 3 - 5 MPa (400 - 700 psi = 57.6 - 100.8 ksf)
• Tensile strength : 2 - 5 MPa (300 - 700 psi = 43.2 - 100.8 ksf)
• Modulus of elasticity : 14000 - 41000 MPa (2 x 106 - 6 x 106 psi = 288000 - 864000 ksf)

The American Concrete Institute (ACI) suggests the following equation for the modulus of elasticity:

$E_{c} = 33\omega _{c}^{1.5}\sqrt{f'_{c}}\; (psi)$

where​

wc = weight of concrete (pounds per cubic foot)

f'c = compressive strength of concrete at 28 days (psi)

AASHTO Load and Resistance Factor Design Manual, or "LRFD"  suggests the following equation:

$E_{c} = 33000K_{1}\omega _{c}^{1.5}\sqrt{f'_{c}}\; (ksi)$

where​

K1 = correction factor for aggregate source (taken as 1.0 unless determined otherwise)

wc = weight of concrete (pounds per cubic foot (pcf))

f'c = compressive strength of concrete at 28 days (psi)

A handy approximate equation:

$E_{c} = 1820\sqrt{f'_{c}}\; (ksi)$

• Permeability : 1 x 10-10 cm/sec (2.8346 x 10-7 ft/day)
• Coefficient of thermal expansion : 10-5 oC-1 (5.5 x 10-6 oF-1)
• Drying shrinkage : 4 - 8 x 10-4
• Drying shrinkage of reinforced concrete : 2 - 3 x 10-4
• Poisson's ratio : 0.20 - 0.21
• Shear strength : 6 - 17 MPa (870 - 2465 psi)
• Specific heat :  0.75 kJ/kg K (0.18 Btu/lboF (kcal/kg oC))