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August 12, 2017 18:08

What is needed for concrete sand - a clear answer to this question

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What sand needed for concrete: quality standards

sand, which is used for the production of concrete, is a loose mixture of grains that were formed by gradual weathering of rocks.It consists mainly of less igneous and sedimentary rocks.If such natural sand absent, the mixture is extracted by crushing an artificial rocks.For the production of concrete sand must meet the standards established by GOST.According to him in the composition should be no more than ten percent of the grains which pass through a sieve of 0.14 mm, and clay, dust and silt impurities should be no more than three per cent of the total weight.

Note!The most harmful is the admixture of clay, as it coats the sand particles and thus reduces adhesion with other materials .Organic substances should be the minimum possible amount, because they do less strength and can even destroy the cement.The sand grains should not be larger than ten millimeters and 10.5 millimeters in size grains of no more than five percent.

begin to sift through the sand should be through a sieve with the biggest mesh.Remains after each screening serve as a basis for its distribution by size (there is a large, small, medium and very fine).To manufacture the concrete structure with large grains with a sufficient number of medium and small grains.Also plays an important role, its density.Thus, cement brand M200, the density of the sand should be about 1550 kilograms per cubic meter.

sand for the production of aerated concrete

A variation is aerated.For its production also needs sand.Cementing cement material for his acts Portland.There are various production technologies, but always used the sand.The greatest strength of the aerated concrete gets when it is prepared in the following ratio: 20 percent Portland cement, lime and 40 percent to 40 percent sand.As can be seen, the sand is almost the half of the composition, which makes the material durable.

Note!Standards optionally aerated sand for the same as for the plain concrete.

Sand for aerated concrete must be cleaned of all foreign objects, such as organic matter, stones, lumps of clay and lime.Winnowed it must be on the same system as the conventional concrete mixture.The main role in the quality of manufacturing will play a mixture of sand cleanliness, and thoroughness of its dry prosevki.

amount calculation

For quality material necessary to make the correct ratio of cement and sand.For example, the flow of sand onto a cube of concrete with cement brand M200 will be 667 kilograms.The calculation is as follows: one cubic meter of sand weighs 1,500 kilograms, macadam - 1700 kilograms and cement - 1400 kg.Ready concrete volume will be much more severe.This happens because all of the voids will be filled by mixing fine grains.Therefore, from a cubic meter of dry mix will just 0.65 m3 of ready mix.

Note!Concrete is mixed in a ratio of 1: 3: 5.That is, you need a bucket of cement three buckets of sand and five buckets of rubble.

Therefore, for the preparation of a cubic meter of concrete will have to use a lot more dry components.So, to prepare a mixture of 0.2 cubic meters of cement necessary to take 0.9 m3 of gravel, 185 liters of water and 0.4 m3 of sand.Thus, knowing the proportion of data, you can carry out your own calculations of the ratio of sand to cement.

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