The class, or brand of concrete, is the most important and important indicator of the quality of the mixture, which you need to pay close attention to when buying. Indicators of mobility, frost resistance and water resistance are always relegated to the background.
Necessary
an architectural project with strength class calculations
Instructions
Step 1
The strength of concrete is a variable parameter, it can be calculated finally only after the completion of the hardening process, and this process lasts exactly 28 days. Only after this interval can the design or calculated strength be determined.
Step 2
The main range used in construction is calculated from grades 100, 200, 300, 400, 500. The strength class directly depends on the proportions of cement in the prepared mixture. The main range ranges from 7, 5 to 40; full - from B 3, 5 to B 80.
Step 3
Your design documentation, drawn up by a professional architect to obtain a building permit, must specify the concrete grade required for foundation and masonry work. Order concrete mix based on these parameters.
Step 4
To check if the concrete really meets the declared class, make small boxes measuring 15x15x15. Moisten the molds, pour the concrete mixture, pierce it with a piece of reinforcement. Place the molds in a room with a temperature of 20 degrees and a humidity of 90%. Contact an independent building laboratory after 28 days. Test concrete cubes will be checked with a sclerometer using a shock pulse, ultrasonic and destructive methods.
Step 5
If you buy concrete without checking, then remember that a self-respecting company will always produce a mixture according to the declared characteristics. The strongest grade will be made of 800 Portland cement, which corresponds to class B 60, the average strength of such concrete is 786 kgf / cm2. This type of concrete is used for multi-storey buildings. The lowest strength of concrete of the Portland cement brand M50 with class B 3, 5 and strength 46 kgf / cm2.
Step 6
For the construction of a one-story house, it is enough to use the brand of Portland cement M400, class B30 with a strength of 393 kgf / cm2.
