About company Sand sale Mining Our address Development of flooded fields Development of sand and sand deposits Construction sand Our company LLC "Dorstroisintez" offers for delivery from a warehouse in Moscow non-metallic building materials, including such as construction sand (alluvial KF-3.5 and KF-2.0) What can be mysterious about the sand? Let's not rush to answer, but let's see how this natural material is given in textbooks and standards. It turns out that things are not so simple. The first indicator is the size of the sand grains. Different sources give different sizes. The Polytechnic Dictionary states that sand is fragments of rocks and minerals rounded to varying degrees, ranging in size from 0.1 to 1 mm, textbooks on soil science - from 2 to 0.05 mm, and encyclopedic dictionaries start counting from 1 mm or less. Construction sand standards limit sand grain sizes from 5 to 0.14 mm, but the raw material standards for gravel and sand give values of 5 to 0.05 mm. The second indicator of the quality of building sand (after its granulometry) is the content of undesirable impurities in it, for example, dust. This is especially important for concrete, where its amount should not exceed 3 percent on average. But what does GOST 10268-80 "Heavy concrete" mean by dust? This is the content (up to 15 percent) of particles passing through a sieve with openings of 0.14 mm. But here is also the most valuable fraction of sand (0.14-0.005 mm). It fills the voids in the cement-sandy mass of concrete, ensuring the density and strength of the concrete. You can, of course, make a table on three legs - it will be cheaper, but push it - it will fall. The table is stable on four legs. So it is with the introduction of a fine fraction. When sanding up, hydraulic operators remove not only dust, but also fine sand (less than 0.14 mm). Now, indeed, the child is being thrown out along with the water. In the same GOST there is one more wisdom: "harmful impurities". This is a list of 27 types of rocks and minerals, which include mica, gypsum, flint, etc. In the European part, the overwhelming mass of sands consists of grains of quartz, flint, fragments of sandstone and limestone with an insignificant admixture of other minerals and rocks. But they are not harmful impurities. In Siberia and the Far East, rivers, eroding volcanic and metamorphic rocks, somewhat change the composition of building sand. Fragments of schists, basalts, andesites, cherts with a negligible fraction (0.01-0.05 percent) of mica appear in it. And in the deserts of Central Asia and on the sea coasts, the sand contains gypsum and halite (table salt). However, since the GOST does not indicate the tolerance standards for these impurities, the list of harmful impurities psychologically adjusts laboratory workers to reject any sand, even if it contains, for example, ten grains of flint or gypsum or mica leaves. If you are interested, you can always contact us at the following address: Our coordinates: Our address: 125222, Moscow, per. Uvarovskiy, 3 Our phones: +7 (495) 754-72-73, 759-94-25 E-Mail: dss125222@mail.ru Contact person: Vladimir Vladimirovich Alloy building sand KF 3.5 KF 2.0 non-metallic building materials sale by Dorstroisintez LLC make a website in megagroup.ru