Advice 1: How to determine the brand of cement

As a rule, the brand of cement is determined by a special notation on the package. However, in some cases, for example when the packing is gone or corrupted, you can determine the brand of cement experimentally.
How to determine the brand of cement
You will need
  • - cement;
  • - sand;
  • water;
  • - special forms for cement;
  • - a cap;
  • - steaming chamber;
  • - weights with the designation of mass.
Mix mortar of cement, using standard sand. The ratio of cement and sand shall be 1:3. The ratio of water-cement ratio should be not less than 0.4 (for example, 1 kg of cement have 400 g of water).
From the obtained cement mould special shaped bars, size 4х4х16 see
Place the sample in a special chamber or cover them with a cap. It is obligatory to ensure sufficient humidity. For this purpose put near a forms a container of water. Leave to Mature samples under the hood for a day.
Remove the cubes from formwork-forms and place them in the steaming chamber. After an intense steaming, check the strength of the test samples of cement on a bend. To do this, set a cement block on two pillars. The center of the block must remain free. In the end, the entire structure should resemble an impromptu bridge. In the middle of the block put one weight. Weight at which to break the bar should be remembered. Using this figure, as well as special formulas and ratios, determine the load in compression and brand of cement. For each brand has its own formula.
Letter standing after the cement is the intensity strength. Please note that under normal intensity, this letter is not indicated. And if the P still stands, so the cement has high early strength.
Useful advice
In order to learn how to determine the grade and composition of cement, consider this example: HRC II/B-W-400 P.

In this case, PTS is the Portland cement. The Roman numeral is the type of cement. Type I - the content of mineral additives less than 5%; cement type II contains from 6% to 35% of mineral admixtures; and type III – means the content of additives in the form of slag from 35% to 80%. The following letter is an additional indicator to the indicated type. If the letter A, then the content of additives varies from 6% to 20%; – additives from 21% to 35%. Then, specify what type of mineral supplements is present in the cement: the letter s – slag; Z - fly ash; P – pozzolan. Next, the grade of cement.

Advice 2: How to determine the class of concrete

Classor grade of concrete is the main and important indicator of the quality of the mixture that you need to pay close attention when buying. Indicators of mobility, frost resistance and impermeability are always sidelined.
How to determine the class of concrete
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.

Advice 3: How to calculate the amount of cement

To buy exactly as much as required – nothing more and nothing less is the exercise of reasonable efficiency. Especially when it comes to such material as cement, which is contraindicated for long storage because of its hygroscopicity. It may be that opening over time the bag, you instead of soft fine fraction will find solid rock. How to calculate the exact amount of cement that may be required forthe laying of the screed, the pouring of the Foundation or plaster walls?
How to calculate the amount of cement
You will need
  • calculator;
  • - ruler or tape measure.
Choose the brand of solution which is suitable for the type of work you intend to perform. Depending on the nature of the work may require mortar (sand-cement, concrete, spaciality, etc.) of different strength (of the brand). In particular:

for floor screed apply a mortar brands M200 – M300;
- for masonry walls of brick or blocks – M50 – M100;
- for the manufacture of cinder blocks – M35 – M50;
- for the manufacture of clay blocks – the M50 – M100;
- for plastering the walls of the house – the M50 – M100;
- for foundations – concrete solution M 200 – M 300.
Determine the brand of cement that will be required to provide the desired brand of solution. For sand-cement-grade of cement should be approximately two to three times to surpass the brand design solution. If you need a brand solution M200, you should purchase cement M400 or M500. For casting cellular concrete blocks (cinder block, concrete, etc.) the grade of cement should exceed the brand of solution 6-8 times. So for the production of cellular concrete grade M50 you will need a cement M300 or M400.
Calculate the required volume of the solution. For floor screed, wall plaster, basement and other similar monolithic structures made of concrete required volume is calculated by multiplying the appropriate parameters (thickness, length, width) to each other. The required amount of mortar for masonry shall be taken equal to 0,2 – 0,25 m3 per 1 m3 of masonry, to the erection of walls from blocks of standard size - 0,05 m3 solution per 1 m3 of masonry.
Find in the Internet the recipe to prepare the solution you need brand, using a certain brand of cement(step 2). The most widely used is the cement M400. With its use it is possible to prepare solutions of very wide application. In particular, for the preparation of 1 m3:

- claydite-concrete M75 will need 250 kg of cement M400;
- cinder M50 – 200 kg;
concrete for the Foundation M300 – 380 kg;
- sand-cement plaster or masonry mortar M100 – 340 kg.
On the basis of the required volume of solution (step 3) and the amount of cement required to make 1 m3 of the solution (step 4), calculate the amount of cement that would be needed. For example, if you add a garage made of bricks, the volume of which is 10 m3, the required amount of cement is calculated as follows:

10*0,25*340=850 kg

- 10 – the volume of brickwork in m3;
- 0.25 – flow rate of the solution per 1 m3 of masonry in m3;
- 340 – the amount of cement required for preparing the 1 m3 of solution kg.
Useful advice
Buying cement, you need to keep in mind that the strength of the mortar made from it is reduced in proportion to storage time of the binder. If you are using stale cement, the amount in solution should be increased compared to recommended.

The strength of the solution affects the quality of the sand. Cited all sources data on cement consumption suggest the use of middle-sized sand. If you use fine-grained sand fraction, the consumption of cement should be increased.
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