Procedure for the manufacture of concrete - cement proportions of sand and gravel

reasons, which may require a separate manufacture of concrete, not too little, for example, the distance from the construction of roads and settlements, a small amount of material required, which does not agree to bring suppliers.In any case, knowing the correct proportions of materials and mixing technique, the concrete can be prepared by hand.

Materials

As with any building material for the preparation of high-quality concrete is important to "correct" the raw material.Only four basic components: cement, sand, filler and water.General requirements - ingredients must be clean and free of impurities, and the first three - and even dry.

Cement - the basis of high-quality concrete, it must be fresh, as the storage of its properties deteriorate.Most recipes are designed for the use of the most common brand of cement M500.If the presence of only the M300 or M400, for the conversion of their number must use the correction factors.It is true such a rule: to get the concrete of a certain brand, you need to use cement to 2 times greater brand.Measure out the cement is particularly convenient, as it is sold in bags, often for 50 kg.

for concrete production required a river or building sand , definitely not pure clay, which leads to cracking of concrete at temperature drops.
filler can be gravel or crushed stone fraction 10-20 mm.They should be uniform, without impurities and debris granite chips.For the preparation of concrete with his hands it is more convenient to use a filler with a fine fractions, as though it is heavier, but it is more convenient solution was mixed with a spade.

Water suitable tap, river or lake may include organic matter, leading to a deterioration of the quality of concrete.

proportions

Measure out the components must be strictly in accordance with the recommended proportions, as their violation leads to concrete defects.For example, if you use more than stated in the proportion of cement, the concrete will turn brittle.The most common systems for residential buildings next to the concrete formulation ratios cement: sand: gravel

proportions in the recipe are listed by weight, so that the required balances may be Canter 20-30 kg.For example, for the preparation of common concrete grade M300 need to take 10 kg of cement, 24 kg and 43 kg of sand gravel.

Water is added at the rate of 30-50% by weight of cement.For a more dense concrete minimal amount of water used for more plastic and fluid (as by pouring the foundation) - greater.However, an excessive amount of water is detrimental to the strength of the concrete as both after evaporation material in the cavity remain.

process of preparing concrete

If you have to mix concrete by hand, it is best to use a large, but not a deep metal container, in extreme cases, clean concreted area.The container poured a measured amount of sand and cement and mixed thoroughly with a shovel until smooth.Adding gravel, and the mixture is stirred again.Then, carefully, so as not sprayed, poured into water, and concrete is kneaded until completely smooth.Ready concrete should be used for an hour.

concrete preparation manually is very time-consuming activity, so it is best to use a compact concrete mixer.The operating unit is filled approximately one-third of the prepared water is poured cement, and kneaded until smooth.Then, in small batches added sand.Once all three components mix well, lay gravel and topped up with the remaining water.If the solution is not used all at once, the mixer should be left switched on.

Produce concrete alone, even without knowing the proportions, is not easy.It is necessary to select and accurately measure the ingredients, mix them thoroughly, the only way to achieve quality, approximate to industrial.