You will need
  • - architectural project with the calculations of the strength class.
Strength of concrete is a variable parameter, it can be established only after completion of the hardening process, and this process lasts exactly 28 days. Only after this period it is possible to define a design or design strength.
Main range is used in construction, calculated from the brands 100, 200, 300, 400, 500. Class strength depends on the proportions of cement made of a mixture. The main range varies from 7.5 to 40; full – from 3.5 to 80.
In your project documentation prepared by the professional architect to obtain a building permit, must indicate the class of concreterequired for the Foundation and masonry work. On the basis of these parameters order the concrete mix.
To check whether the concrete complies with the declared class, make small boxes the size of 15х15х15. Moisten the forms, pour the concrete mixture, prostitute it with a piece of rebar. Form put in a room with a temperature of 20 degrees and 90% humidity. After 28 days, please contact an independent construction laboratory. Trial concrete cubes will be checked by sclerometer by impulse, ultrasonic and destructive method.
If you buy the concrete without inspection, then remember that reputable company will always produce the compound according to specs. The most durable brand is made of Portland cement 800 that corresponds to the class of 60, the average strength of such concrete is equal to 786 kg/cm2. This type of concrete is used for multi-storey buildings. Low strength in the concrete is Portland cement grade M50 with a 3.5 and a strength of 46 kgf/cm2.
For the construction of one-storey houses, it is sufficient to use a brand of Portland cement M400, class B30 with the strength of 393 kgf/cm2.