**Basic properties**

The following Table gives the compressive strengths (based on cylinders and cubes), modulus of elasticity and tensile strength for various strength classes of normal weight concrete. They are taken from Table 3.1 of the Eurocode 2, which gives additional properties as well as values for other strength classes. It should be notes that these are characteristic values and should be modified as appropriate for design purposes.

**Strength class** |
**20/25** |
**25/30** |
**30/37** |
**35/45** |
**40/50** |
**45/55** |
**50/60** |

Cylinder strength (MPa) |
20 |
25 |
30 |
35 |
40 |
45 |
50 |

Cube strength (MPa) |
25 |
30 |
37 |
45 |
50 |
55 |
60 |

Modulus of elasticity (GPa) |
30 |
31 |
32 |
34 |
35 |
36 |
37 |

Tensile strength (MPa) |
2.2 |
2.6 |
2.9 |
3.2 |
3.5 |
3.8 |
4.1 |

For lightweight aggregate concrete, the values for modulus of elasticity and tensile strength given in the Table should be multiplied by a factor equal to [oven dried density/2200]

^{2}. For example, the modulus of elasticity of a lightweight aggregate concrete of strength class 25/30 and oven dry density 1850 kg/m

^{3} should be taken as 31 x [1850/2200]

^{2} = 21.9 GPa.