Choosing and buying a particular type and grade (class) of concrete mix is determined by your project. If the project not, you can trust the recommendations of your builders. They may advise the concrete of a brand or class. If you have some doubts about the competence of your builders, you can try to understand yourself.

The figures mark the concrete (m-100 m-200, etc.) denote the (average) limit of compressive strength in kg / cm. Verification of conformity necessary parameters compress a special press cubes or cylinders, cast from the sample mixture, and aged for 28 days of normal hardening.

In modern concrete projects in the designated classes. In general, the class of concrete - a parameter akin to the brand, but with some nuances: in DM is the mean of strength in the classroom - with a guaranteed supply of strength with a coefficient of variation of 13%. However, for you it does not have any value. I do not want you fooling with coefficients of variation of strength, and other technical nuances. In the project documentation, if you are sure there must be given: a concrete class must be used. In accordance with the ST SEV 1406, all the modern design requirements for concrete are specified precisely in the classroom. I do not know - as far as observed, because 90% of construction companies for some reason bought the concrete in DM.

For you the main thing - that brought you the concrete correspond to the brand, you actually ordered. Check course you can, but not immediately. What should be done.

The unloading of concrete, sampling and cast two or three blocks in size 10h10h10 see or 15h15h15 see to do this is to put together a special form of plates desired size. Before you pour concrete into forms, it is desirable to humidify the drawers, so that dry wood not take a lot of moisture from the concrete, thereby adversely affecting the process of hydration of cement. Should be flooded with a mixture of proshtykovat piece valve or something similar: poked into the mixture as crushed potato puree to a stained sample were not formed blank space (shells), came out excess air, and the mixture was compacted. You can also compress a mixture of a hammer on the sides of boxes. Cast cubes stored at moderate temperatures (about 20 degrees) and high humidity (90%).

After 28 days you can in good conscience bring all this splendor to any independent laboratory. There you had suppressed all this and make a verdict - whether concrete claimed mark or does not match. However, do not have to wait 28 days for this purpose there are intermediate stages of hardening in the age of 3, 7, 14 days. During the first 7 days of concrete is gaining about 70% of the estimated strength (of course subject to the normal temperature) in the damp and cold season, setting deadlines and concrete during its hardening significantly increased.

Время на сервере: 04.09.2010 00:33:30

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