Brands and types of building sand, their features. Building sand is the most important component of various mortars and concretes Marking of building sand

What are the types of building sand?

crushed sand- sand obtained by crushing gravel rocks. The grain size of crushed sand should not exceed 5 mm;

Fractionated sand- sand, divided into several fractions using special equipment;

Sand from crushing screenings- sand obtained from screenings of crushing rocks and industrial waste. The grain size of crushed sand should not exceed 5 mm.

How is building sand graded?

Answer: According to GOST 8736-93, depending on the grain composition, building sand is divided into two main groups by size:
Class I - very coarse sand, coarse sand, coarse sand, medium and fine sand;
Class II - very coarse sand, coarse sand, coarse sand, medium sand, fine sand, very fine sand, fine and very fine sand.
Each group of sand is characterized by a particle size modulus.

Tab. Sand groups by size

Answer: The strength grade of sand from screenings of crushing rocks is characterized by indicators of tensile strength, established by laboratory

Tab.

What is a radiological and hygienic assessment of construction sand?

Answer: In accordance with GOST 8736-93, building sand must be given a radiation-hygienic assessment, the results of which determine the scope of its application. Sand depending on the values ​​of specific effective activity natural radionuclides BUT eff apply:

At BUT eff up to 370 Bq/kg - in newly constructed residential and public buildings;

At BUT eff st. 370 to 740 Bq/kg - for road construction within the territory settlements and zones of promising development, as well as during the construction industrial buildings and structures;

At BUT eff st. 740 to 1500 Bq/kg - in road construction stumps of settlements.

What characteristics of building sand must the manufacturer report to the consumer?

Answer: In accordance with GOST 8736-93, the manufacturer must inform the consumer of the following characteristics established by geological exploration:

Mineralogical and petrographic composition, indicating rocks and minerals classified as harmful components and impurities;

Void;

True density of sand grains.

What are the standards for the permissible content of harmful rocks, minerals and impurities in building sand used as aggregates for mortars and concretes?

Answer: In accordance with GOST 8736-93, these indicators should not exceed the following values:
- amorphous varieties of silicon dioxide, soluble in alkalis (chalcedony, opal, flint, etc.) - no more than 50 mmol / l;
- sulfur, sulfides, except for pyrite (marcasite, pyrrhotite, etc.) and sulfates (gypsum, anhydrite, etc.) in terms of SO 3 - no more than 1.0%, pyrite in terms of SO 3 - no more than 4% by mass;
- mica - no more than 2% by weight:
- halide compounds (halite, sylvin, etc.), including water-soluble chlorides, in terms of chloride ion - no more than 0.15% by weight;
- coal - no more than 1% by weight;
- organic impurities (humic acids) - less than the amount that gives the sodium hydroxide solution a color corresponding to the color of the standard or darker than this color. The use of sand that does not meet this requirement is allowed only after receipt positive results tests of sand in concrete or mortar for durability characteristics.

How is the amount of sand supplied to the consumer determined?

Answer: In accordance with GOST 8736-93, the amount of building sand is determined by weight or by volume. Sand supplied by road and rail cars is weighed. The mass of sand carried water transport, determined by the draft of the bottom. The amount of sand from units of mass to units of volume is recalculated according to the values ​​of the bulk density of sand, determined at its moisture content during shipment. The supply contract indicates the calculated sand moisture content adopted by agreement of the parties.

What documents should be accompanied by a batch of supplied sand?

Answer: In accordance with GOST 8736-93, the manufacturer is obliged to accompany each batch of supplied construction sand with a document on its quality in the established form, which must indicate:

Manufacturer's name and address

Number and date of issue of the document;

Batch number and amount of sand;

Class, particle size module, total residue on sieve No. 063;

Specific effective activity of natural radionuclides in sand;

Wagon numbers and vessel number, invoice numbers;

Designation of this standard.

How to transport and store building sand?

Answer:construction sand allowed to be transported in open railway wagons, ships and cars in accordance with the rules for the transportation of bulk cargo.

During shipment and storage, it is necessary to ensure conditions that prevent clogging, freezing and erosion of sand.

Contains grains different size- from 0.16 mm in diameter to 5.0 mm. All particles larger than 5 mm and smaller than 0.16 mm are not considered sand, although they may be in it.

Why determine the size of grains of sand?

The analysis of sand by grain size is essential in construction business, because its characteristics allow you to establish the brand of material and suitability for use in mortar or layer.

When examining the grain composition of sand by sieving on several sieves, the amount of sand with a particle size of 2.5-5.0 mm, 1.25-2.5 mm, 0.63-1.25 mm, 0.315-0 is determined as a percentage of the total mass. 64 mm, 0.16-0.315 mm.

The data of the obtained measurements allow us to construct a screening curve that characterizes its granulometric composition and gives an understanding of in what concrete mixtures material can be used. An integrated display of the characteristics of the grain composition is the fineness modulus.

What is the size modulus (M k)?

The modulus of sand size is a conditional dimensionless value that makes it possible to estimate the prevailing size of its grains. Here is how the material is used in practice depending on the value of M k:

• for the most quality concrete grades B25 and above use sand with M to at least 2.5 (large grains);
• in mixtures B15, sand with Mk = 2-2.5 (medium size) is used;
• in the preparation of mixtures for underwater concrete, molding stone and mortars - sand with Mk equal to 1.5-2.0 (fine grains);
• for the production of fine construction compounds use sand of a very fine fraction with M k \u003d 1.0-1.5.

Determination of the modulus of sand size

In accordance with GOST 8736-2014, the sand fineness module is measured in this way:

1. From a 2-kg sample, particles larger than 5 mm are first separated using sieves;
2. One kg is taken from the remaining mass and sieved sequentially through sieve cells ranging in size from 2.5 mm to 0.16 mm (5 sieves in total). The amount of sand, as a percentage of 1000 g, not sieved through each sieve, is recorded on paper. Screening during operations is stopped when the sand stops passing through the cells.
3. The sand size modulus is calculated by the formula:
   M k \u003d (A2.5 + A1.25 + A0.63 + A0.315 + A0.16) / 100,
   where A ... - total residues on five sieves as a percentage of the total mass.

From a physical point of view, this formula reflects the weighted average number of grains of sand of greater or lesser size per unit mass of the product. The more large grains in the sand sample under study, the higher Mc is.

However, this rule does not always apply. Experts have noticed that two batches of fine sand with grains of different sizes can have equal Mk values. Therefore, for a complete qualitative characteristics sand, in addition to M k, other indicators are also used, namely:

• grain size distribution;
• the amount of dust particles;
• the content of lumps of clay;
• the content of weed impurities;
• bulk density;
• the presence of organic impurities;
• grain density;
• the content of harmful components;
• activity of radionuclides and others.

The quality of sand and the priorities of use are most often assessed by specialists by the totality of all available characteristics, and not only by the fineness modulus.

Classification of sand by size modulus

The value of M to divides the sand into groups:

• very thin (size modulus up to 0.7);
• thin (from 0.7 to 1.0);
• small (from 1.0 to 1.5);
• very small (from 1 to 1.5);
• small (1.5-2.0);
• medium (2.0-2.5);
• large (2.5-3.0);
• increased size (3.0-3.5).

Determination of the sand size modulus in accordance with GOST is a standard analytical operation and is performed in the laboratories of all companies involved in the trade of this product.

In our assortment you can always purchase, and many other types of high-quality sand.

INTERSTATE STANDARD

SAND FOR CONSTRUCTION WORKS

TECHNICAL CONDITIONS

INTERSTATE SCIENTIFIC AND TECHNICAL COMMISSION
FOR STANDARDIZATION AND TECHNICAL REGULATION
IN CONSTRUCTION (MNTKS)

Foreword

1 DEVELOPED by the institute VNIPIIstromsyre with the participation of SoyuzDorNII, NIIZhB, TsNIIOMTP Russian Federation

INTRODUCED by the Ministry of Construction of Russia

2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (MNTKS) on November 10, 1993

3 ENTERED INTO FORCE July 1, 1995 as state standard of the Russian Federation by the Decree of the Ministry of Construction of Russia dated November 28, 1994 No. 18-29

4 INSTEAD OF GOST 8736-85, GOST 26193-84

INTERSTATE STANDARD

SAND FOR CONSTRUCTION WORKS

Technicalconditions

Sand for construction works.
Specifications

Introduction date 1995-07-01

1 AREA OF USE

This standard applies to natural sand and sand from rock crushing screenings with a true grain density of 2.0 to 2.8 g / cm 3, intended for use as an aggregate for heavy, light, fine-grained, cellular and silicate concretes, mortars, preparation of dry mixes, for the device of the bases and coverings highways and airfields.

The requirements of this standard do not apply to graded and crushed sands.

The requirements of this standard, set out in clauses 4.4.1, 4.4.3, 4.4.7, 4.4.8, sections 5 and 6, are mandatory.

2 DEFINITIONS

The following terms are used in this standard.

natural sand- inorganic bulk material with a grain size of up to 5 mm, formed as a result of the natural destruction of rocky rocks and obtained during the development of sand and sand-gravel deposits without the use or with the use of special processing equipment.

(Changed edition. Rev. No. 1).

crushed sand- sand with a grain size of up to 5 mm, made from rocks and gravel using special crushing and grinding equipment.

Graded sand- sand divided into two or more fractions using special equipment.

Sand from crushing screenings- inorganic bulk material with a grain size of up to 5 mm, obtained from rock crushing screenings in the production of crushed stone and from waste from the enrichment of ores of ferrous and non-ferrous metals and non-metallic minerals and other industries.

3 TECHNICAL REQUIREMENTS

3.1 Sand must be manufactured in accordance with the requirements of this standard according to the technological documentation approved by the manufacturer.

3.2 Sand, depending on the values ​​of standardized quality indicators (grain composition, content of dust and clay particles), is divided into two classes.

3.3 Main parameters and dimensions

3.3.1 Depending on the grain composition, sand is divided into groups according to size:

I class - very coarse (sand from crushing screenings), increased fineness, coarse, medium and fine;

II class - very coarse (sand from screenings of crushing), increased size, coarse, medium, fine, very fine, fine and very fine.

3.3.2 Each group of sand is characterized by the value of the fineness modulus indicated in table 1.

Table 1

3.3.3 The total balance of sand on a sieve with mesh No. 063 must correspond to the values ​​\u200b\u200bspecified in table 2.

table 2

Percent by weight

Table 3

3.4Characteristics

Table 4

As a percentage by weight, no more

3.4.2 Sands from screenings of crushing, depending on the strength of the rock and gravel, are divided into grades. Igneous and metamorphic rocks must have a compressive strength of at least 60 MPa, sedimentary rocks - at least 40 MPa.

The grade of sand from crushing screenings in terms of strength must correspond to that indicated in table 5.

Table 5

3.4.3 Sand intended for use as aggregate for concrete should be resistant to the chemical attack of cement alkalis.

The resistance of sand is determined by the mineralogical and petrographic composition and the content of harmful components and impurities. The list of rocks and minerals classified as harmful components and impurities, and their maximum allowable content are given in Appendix A.

3.4.4 Sand from screenings of rock crushing, having a true grain density of more than 2.8 g / cm 3 or containing grains of rocks and minerals classified as harmful components in an amount exceeding their permissible content, or containing several different harmful components, is released for specific types construction works on technical documents developed in accordance with the established procedure and coordinated with laboratories specialized in the field of corrosion.

3.4.5 It is allowed to supply a mixture of natural sand and sand from crushing screenings with the latter content of at least 20% by weight, while the amount of the mixture must meet the requirements of this standard for the quality of sands from crushing screenings.

3.4.6 The manufacturer must inform the consumer of the following characteristics established by geological exploration:

Mineralogical and petrographic composition indicating rocks and minerals classified as harmful components and impurities;

Void;

True density of sand grains.

3.4.7 Natural sand, when treated with a sodium hydroxide solution (colorimetric test for organic impurities according to GOST 8735), should not give the solution a color that matches or is darker than the color of the standard.

3.4.8 Sand must be given a radiation-hygienic assessment, the results of which determine the scope of its application. Sand depending on the values ​​of the specific effective activity of natural radionuclides BUT eff apply:

At BUT eff up to 370 Bq/kg - in newly built residential and public buildings;

At BUT eff st. 370 to 740 Bq / kg - for road construction within the territory of settlements and zones of promising development, as well as during the construction of industrial buildings and structures;

At BUT eff st. 740 to 1500 Bq/kg - in road construction of the stump of settlements.

If necessary, in the national norms in force on the territory of the state, the value of the specific effective activity of natural radionuclides can be changed within the limits indicated above.

(Changed edition. Rev. No. 1, 2).

3.4.9 Sand must be free of foreign contaminants.

4 ACCEPTANCE RULES

4.1 Sand must be accepted by the service technical control manufacturer.

4.2 To check the compliance of the sand quality with the requirements of this standard, acceptance and periodic tests are carried out.

4.3 Acceptance tests at the manufacturer are carried out daily by testing one replacement sample taken in accordance with GOST 8735 from each production line.

At acceptance control determine:

Grain composition;

4.4 When periodically testing sand, determine:

Once a quarter - bulk density (bulk density at moisture during shipment is determined as necessary), as well as the presence of organic impurities (humic substances) in natural sand;

Once a year and in each case, changes in the properties of the developed rock - the true density of grains, the content of rocks and minerals classified as harmful components and impurities, the strength grade of sand from crushing screenings, specific effective activity natural radionuclides.

Periodic monitoring of the indicator of specific effective activity of natural radionuclides is carried out in specialized laboratories accredited in accordance with the established procedure for the right to conduct gamma spectrometric tests or in radiation metric laboratories of supervisory authorities.

In the absence of geological exploration data on the radiation-hygienic assessment of the deposit and the conclusion on the class of sand, the manufacturer conducts a radiation-hygienic assessment of the developed rock sections using the express method directly in the face or in warehouses finished products(alluvium map) in accordance with the requirements of GOST 30108.

4.5 Sampling and preparation of sand samples for quality control at the manufacturer is carried out in accordance with the requirements of GOST 8735.

4.6 Delivery and acceptance of sand is carried out in batches. A batch is considered to be the amount of material that is simultaneously supplied to one consumer in one train or in one vessel. On shipment by car the batch is the amount of sand shipped to one consumer during the day.

5.7 When controlling the quality of sand, the consumer must apply the sampling procedure given in 5.8-5.11. With unsatisfactory results control check on grain composition and the content of dust and clay particles, a batch of sand is not accepted.

4.8 The number of incremental samples taken for the control check of the quality of sand in each batch, depending on the volume of the batch, must be at least:

Lot size Number of increments

Up to 350 m ............................................... ................................... ten

St. 350 to 700 m .............................................. .......................... fifteen

St. 700 m ............................................... .................................... ten

From incremental samples, a combined sample is formed, which characterizes the controlled lot. Averaging, reduction and sample preparation are carried out according to GOST 8735.

4.9 For a control check of the quality of sand shipped by rail, point samples are taken when unloading wagons from the sand stream on belt conveyors used to transport it to the consumer's warehouse. When unloading the wagon, five point samples are taken at regular intervals. The number of wagons is determined taking into account obtaining the required number of incremental samples in accordance with 5.8.

Cars are selected at the direction of the consumer. If the batch consists of one wagon, five point samples are taken during its unloading, from which a combined sample is obtained.

If continuous transport is not used during unloading, point samples are taken directly from the wagons. To do this, the sand surface in the car is leveled and holes 0.2-0.4 m deep are dug at the sampling points. The sampling points should be located in the center and at the four corners of the car, while the distance from the sides of the car to the sampling points should not less than 0.5 m. Samples from the holes are taken with a scoop, moving it from bottom to top along the walls of the hole.

4.10 For a control check of the quality of sand supplied by water transport, point samples are taken during unloading of ships. In the case of using belt conveyors for unloading, incremental samples are taken at regular intervals from the sand flow on the conveyors. When unloading the ship with clamshell cranes, spot samples are taken with a scoop at regular intervals as they are unloaded directly from the newly formed sand surface in the ship, and not from the holes.

For a control check of sand unloaded from ships and laid on alluvium maps by hydromechanization, point samples are taken in accordance with 2.9 GOST 8735.

4.11 For a control check of the quality of sand shipped by road, point samples are taken when unloading cars.

In the case of using belt conveyors for sand unloading, point samples are taken from the sand flow on conveyors. When unloading each car, one point sample is taken. The number of cars is determined taking into account obtaining the required number of incremental samples according to 5.8. Cars are chosen at the direction of the consumer.

If the lot consists of less than ten cars, sand samples are taken from each car.

If conveyor transport is not used when unloading cars, point samples are taken directly from cars. To do this, the surface of the sand in the car is leveled, a hole is dug in the center of the body with a depth of 0.2-0.4 m. Sand samples are taken from the hole with a scoop, moving it from bottom to top along the wall of the hole.

4.12 The amount of sand supplied is determined by volume or mass. Sand measurement is carried out in wagons, ships or cars.

Sand shipped in wagons or cars is weighed on truck scales. The mass of sand shipped in ships is determined by the ship's draft.

The amount of sand from units of mass to units of volume is recalculated according to the values ​​of the bulk density of sand, determined at its moisture content during shipment. The supply contract indicates the calculated sand moisture content adopted by agreement of the parties.

4.13 The manufacturer is obliged to accompany each batch of supplied sand with a document on its quality in the established form, which must indicate:

Name of the manufacturer and its address;

Number and date of issue of the document;

Batch number and amount of sand;

Wagon numbers and vessel number, invoice numbers;

Class, particle size module, total residue on sieve No. 063;

Specific effective activity of natural radionuclides in sand in accordance with 5.4;

Designation of this standard.

5 CONTROL METHODS

5.1 Sand tests are carried out in accordance with GOST 8735.

5.2 Specific effective activity of natural radionuclides in sand is determined according to GOST 30108.

6 TRANSPORT AND STORAGE

6.1 Sand is transported in open railway wagons and ships, as well as cars in accordance with the rules approved in the established manner for the carriage of goods by the appropriate mode of transport and stored in the warehouse of the manufacturer and consumer in conditions that protect the sand from contamination.

When transporting sand by rail, the following requirements must also be met. Specifications loading and fastening of cargoes approved by the Ministry of Railways.

6.2 When shipping and storing sand in winter time the manufacturer must take measures to prevent freezing (shoveling, processing special solutions etc.).

APPENDIX A

(mandatory)

The permissible content of rocks and minerals classified as harmful components and impurities in sand used as aggregate for concrete and mortar should not exceed the following values:

Amorphous varieties of silicon dioxide, soluble in alkalis (chalcedony, opal, flint, etc.) - no more than 50 mmol / l;

Sulfur, sulfides, except for pyrite (marcasite, pyrrhotite, etc.) and sulfates (gypsum, anhydrite, etc.) in terms of SO 3 - no more than 1.0%, pyrite in terms of SO 3 - no more than 4% by weight ;

Mica - no more than 2% by weight:

Haloid compounds (halite, sylvin, etc.), including water-soluble chlorides, in terms of chlorine ion - no more than 0.15% by weight;

Coal - no more than 1% by weight;

Organic impurities (humic acids) - less than the amount that gives the sodium hydroxide solution (colorimetric sample according to GOST 8267) a color corresponding to the color of the standard or darker than this color. The use of sand that does not meet this requirement is allowed only after receiving positive results of tests of sand in concrete or mortar for durability characteristics.

The permissible content of zeolite, graphite, oil shale is established on the basis of studies of the effect of sand on the durability of concrete or mortar.

Grain composition– content by weight of groups of grains (fractions) loose and crushed mineral minerals different fineness in relation to the mass of the studied material sample.

The sandy material contains in its composition gravel particles larger than 5 mm, dust and clay fractions smaller than 0.05 mm.

Necessary equipment : laboratory scales; set of sieves with round holes diameter 10; 5 and 2.5 mm and grids No. 1.25; 0.63; 0.315; 0.14; drying cabinet.

Conducting a test. The prepared analytical sand sample of at least 2000 g is dried to constant weight and sieved through sieves with round holes with diameters of 10 and 5 mm.

The residues on the sieves are weighed and the content of gravel fractions in the sand with a grain size of 5 to 10 mm () and more than 10 mm () is calculated as a percentage by weight according to the formulas:

; (1)

; (2)

where is the residue on a sieve with round holes with a diameter of 10 mm, g; - residue on a sieve with round holes with a diameter of 5 mm, g; - weight of the sample, g.

From a part of the sand sample that has passed through a sieve with holes with a diameter of 5 mm, a sample weighing at least 1000 g is taken to determine the grain composition of the sand.

The prepared sample of sand is poured into a column of sieves with round holes of 2.5 mm and with grids No. 1.25; 0.63; 0.315; 0.16 mm, cover with a lid and sieve by hand or mechanically by horizontal shaking. The duration of sieving should be such that during the control intensive manual shaking of each sieve for 1 min, no more than 0.1% of the total mass of the sieved sample passes through it. During mechanical sieving, its duration for the device used is determined empirically.

The completeness of the sifting of sand fractions is checked by shaking each sieve over a sheet of paper until the particles stop falling through the sieve. Then the particles that have fallen onto the paper are poured onto the next sieve with smaller holes. This is how sand is sieved, moving from fraction to fraction, until it is completely sieved. Screening is considered complete if there is practically no fall of sand grains.

The fractions remaining after sieving on each sieve and passing into the tray are poured into prepared vessels and weighed with an accuracy of 0.01 g.

The masses of all fractions are summed up and the resulting amount is compared with the mass of sand taken for the experiment. The discrepancy between them is allowed no more than 1%. The loss of sand during sifting is divided into fractions in proportion to their mass. In the case when the deviation of the sum of mass fractions from the sample taken is more than 1%, then the experiment is recommended to be repeated with a new sample.

private remains on each sieve (%) is determined with an accuracy of 0.1% by the formula

where is the mass of the corresponding fraction on a given sieve, g; - mass of dry sand sample, g.

The results of the sieve analysis of sand should be given in table. one.

Table 1

Screening results of an average laboratory sand sample(example)

Note. The mass of the average laboratory sample is 500 g.

Based on the results of the experiment, a sand sifting curve is built (Fig. 2).

It is allowed to disperse the sample during geological exploration after preliminary washing with the determination of the content of dust and clay particles. The content of dust-like and clay particles is included in the calculation of the results of sieving in the mass of particles passing through a sieve with mesh No. 016, and in the total mass of the sample. During mass tests, it is allowed after washing with the determination of the content of dust-like and clay particles and drying the sample to a constant weight, sift a sample of sand (without gravel fraction) weighing 500 g.

GOST 8736-2014

Group G17

INTERSTATE STANDARD

SAND FOR CONSTRUCTION WORKS

Specifications

Sand for construction works. Specifications

ISS 91.100.15

Introduction date 2015-04-01

Foreword

Objectives, basic principles and basic procedure for work on interstate standardization are established by the "Interstate standardization system. Basic provisions" and "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for the development, adoption, application, updating and cancellation"

About the standard

1 DEVELOPED by the Federal State unitary enterprise"Scientific Research and Design and Survey Institute for the Problems of Extraction, Transport and Processing of Mineral Raw Materials in Industry building materials"(FGUP "VNIPIIstromsyre")

2 INTRODUCED technical committee according to standardization TC 465 "Construction"

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes of September 30, 2014 N 70-P)

4 Order federal agency on technical regulation and metrology of November 18, 2014 N 1641-st interstate standard GOST 8736-2014 was put into effect as a national standard of the Russian Federation on April 1, 2015.

5 INSTEAD OF GOST 8736-93

Information about changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notification and texts are also placed in information system common use- on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

1 area of ​​use

This standard applies to natural sands with a true grain density of 2.0 to 2.8 g / cm 3 and mixtures of natural sands and sands from crushing screenings intended for use as aggregates for heavy, light, fine-grained, cellular and silicate concretes, building solutions, dry building mixtures, for the construction of foundations and coatings for highways and the foundations of runways and aprons of airfields, roadsides, the production of roofing and ceramic materials, reclamation, landscaping and planning of territories and other types of construction work. This standard does not apply to sands from crushing screenings of dense rocks.

2 Normative references

This standard uses Normative references to the following interstate standards:

4.2.18 Sands should not contain foreign contaminants.

4.2.19 It is allowed to supply mixtures of natural sand and sand from crushing screenings in accordance with GOST 31424-2010 with the content of the latter not more than 20% by weight, while the mixtures must comply with the requirements of this standard.

(Amendment. IUS N 10-2015).

It is allowed to supply mixtures of natural sand and sand from crushing screenings in accordance with GOST 31424-2010 with a content of the latter of more than 20% by weight, while the mixtures must comply with the requirements of GOST 31424-2010. Sand from crushing screenings as part of mixtures, having a true grain density of more than 2.8 g / cm 3 or containing grains of rocks and minerals classified as harmful components in an amount exceeding their permissible content, or containing several different harmful components, is produced for specific types of construction works according to normative and technical documents developed in accordance with the established procedure and coordinated with laboratories specialized in the field of corrosion.

4.2.20 At the request of the consumer, the manufacturer must indicate the following sand characteristics established by geological exploration: - mineralogical and petrographic composition, indicating rocks and minerals classified as harmful components and impurities; - content of organic impurities; - true density of sand grains.

4.3 Radiation hygiene assessment Sands should be given a radiation-hygienic assessment, the results of which determine the scope of its application. Sand depending on the values ​​of the specific effective activity of natural radionuclides A eff apply:

A eff up to 370 Bq/kg - in newly constructed residential and public buildings;

A eff St. 370 to 740 Bq / kg - for road construction within the territory of settlements and zones of promising development, as well as during the construction of industrial buildings and structures;

A eff St. 740 to 1500 Bq/kg - in road construction outside populated areas. If necessary, in the national standards in force on the territory of the state, the value of the specific effective activity of natural radionuclides can be changed within the limits indicated above.

5 Acceptance rules

5.1 Sand, enriched sand and graded sand must be accepted by the manufacturer's technical control service.

5.2 To check the compliance of the quality of sand, enriched and graded sands with the requirements of this standard, acceptance control and periodic tests are carried out.

5.3 Acceptance control at the manufacturer is carried out daily by testing a combined replacement sand sample taken in accordance with. During acceptance control, determine:

• grain composition;
• the content of dust and clay particles;
• clay content in lumps;
• the presence of contaminants.

5.4 During periodic testing of sands, the following is determined:

once a quarter bulk density (bulk density at moisture during shipment is determined if necessary) and the presence of organic impurities (humic substances);

once a year and with each change in the properties of the mined rock, the true grain density, the content of rocks and minerals classified as harmful components and impurities, the specific effective activity of natural radionuclides.

Periodic monitoring of the specific effective activity of natural radionuclides is carried out in specialized laboratories duly accredited for the right to conduct gamma-spectrometric tests or in radiation-metric laboratories of supervisory authorities. In the absence of geological exploration data on the radiation-hygienic assessment of the deposit and a conclusion on the class of sands, the manufacturer conducts a radiation-hygienic assessment of the developed rock sections using the express method directly in the face or in the warehouses of finished products (according to the alluvium map) in accordance with the requirements.

5.5 Acceptance and delivery of sand, enriched sand and graded sand is carried out in batches. A batch is the amount of sand specified in the supply contract and simultaneously shipped to one consumer in one train or in one vessel. When shipped by road, a batch is the amount of sand shipped to one consumer during the day.

(Amendment. IUS N 10-2015).

5.6 Sampling and preparation of sand samples for quality control at the manufacturer is carried out in accordance with the requirements.

5.7 When controlling the quality of sands, the consumer must apply the sampling procedure given in 5.8-5.11. If the results of the control check on the grain composition, the content of dust and clay particles and clay in lumps are unsatisfactory, the batch of sand is not accepted.

5.8 The number of incremental samples taken for the control check of the quality of sands in each inspected lot, depending on the size of the lot, must be at least:

From incremental samples, a pooled sample is obtained that characterizes the controlled lot. Averaging, reduction and preparation of the sample is carried out according to .

5.9 For a control check of the quality of sands shipped by rail, point samples are taken when unloading wagons from the sand stream on belt conveyors used to transport it to the consumer's warehouse. When unloading the wagon, five point samples are taken at regular intervals. The number of wagons is determined taking into account obtaining the required number of incremental samples in accordance with 5.8. Cars are selected at the direction of the consumer. If the batch consists of one wagon, five point samples are taken during its unloading, from which a combined sample is obtained.

If conveyor transport is not used during unloading, point samples are taken directly from the wagons. To do this, the sand surface in the car is leveled and holes 0.2-0.4 m deep are dug at the sampling points. The sampling points should be located in the center and at the four corners of the car, while the distance from the sides of the car to the sampling points should not less than 0.5 m. Samples from the holes are taken with a scoop, moving it from bottom to top along the walls of the hole.

5.10 For a control check of the quality of sand supplied by water transport, point samples are taken during unloading of ships. In the case of using belt conveyors for unloading, point samples are taken at regular intervals from the sand flow on the conveyors. When unloading the ship with clamshell cranes, spot samples are taken with a scoop at regular intervals as they are unloaded directly from the newly formed sand surface in the ship, and not from the holes.

For a control check of sand unloaded from ships and laid on alluvium maps by hydromechanization, point samples are taken in accordance with, paragraph 2.9.

5.11 For a control check of the quality of sand shipped by road, point samples are taken when unloading cars.

In the case of using belt conveyors for sand unloading, point samples are taken from the sand flow on the conveyor. When unloading each car, one point sample is taken. The number of cars is determined taking into account obtaining the required number of incremental samples according to 5.8. Cars are selected at the direction of the consumer. If the lot consists of less than ten cars, sand samples are taken from each car.

If conveyor transport is not used when unloading cars, point samples are taken directly from cars. The surface of the sand in the car is leveled, a hole is dug in the center of the body with a depth of 0.2-0.4 m. Sand samples are taken from the hole with a scoop, moving it from bottom to top along the wall of the hole.

5.12 The amount of sand supplied is determined by volume or mass. Sand measurement is carried out in wagons, ships or cars.

Sand shipped in wagons or cars is weighed on truck scales. The mass of sand shipped in ships is determined by the ship's draft.

The amount of sand from units of mass to units of volume is recalculated according to the values ​​of the bulk density of sand, determined at its moisture content during shipment. The supply contract indicates the calculated sand moisture content adopted by agreement of the parties.

5.13 The manufacturer must accompany each batch of supplied sands with a quality document indicating:

• name of the manufacturer and his address;
• number and date of issue of the document;
• name and address of the consumer;
• lot number, name and quantity of material;
• invoice and vehicle numbers;
• grain composition of sand, enriched sand;
• grain composition of the mixture of fractions or the size of narrow fractions (for graded sand);
• the content of dust and clay particles, clay in lumps;
• the content of harmful components and impurities;
• the presence of contaminants;
• bulk density and filtration coefficient (at the request of the consumer) in sand and enriched sand;
• specific effective activity of natural radionuclides;
• designation of this standard.

6 Test methods

6.1 Sand tests are carried out according to.

6.2 The filtration coefficient of sand and enriched sand used in road construction is determined by.

6.4 The specific effective activity of natural radionuclides is determined by .

6.5 The resistance of sands to the effects of harmful components and impurities is determined by the mineralogical and petrographic composition and the content of harmful components and impurities.

7 Transport and storage

7.1 Transport

7.1.1 Sand, enriched sand and graded sand are transported by rail, water and road in accordance with the rules for the carriage of goods in force for a particular type of transport.

7.1.2 Dry graded sand is transported in the form of individual fractions or their mixtures by specialized vehicles (cement trucks, capsules and other means of transportation that provide protection from moisture and contaminants). from 0.1% to 0.5% by weight, unless otherwise specified in other regulatory documents.

7.2 Storage

7.2.1 Sand and enriched sand are stored in the warehouse of the manufacturer and the consumer under conditions that protect them from contamination.

7.2.2 Dry graded sand should be stored in dry closed rooms or closed bunkers (silos) that exclude moisture and contaminants.

7.2.3 When shipping and storing sand and enriched sand in winter, the manufacturer should take measures to prevent freezing (shoveling, treatment with special solutions, etc.).

Annex A (mandatory). Permissible content of harmful components and impurities

The permissible content of rocks and minerals classified as harmful components and impurities in sand used as aggregate for concrete and mortar should not exceed the following values:

• amorphous varieties of silicon dioxide soluble in alkalis (chalcedony, opal, flint, etc.) - no more than 50 mmol / l;
• sulfur, sulfides, except for pyrite (marcasite, pyrrhotite, etc.), and sulfates (gypsum, anhydrite, etc.) in terms of SO 3- no more than 1.0%; pyrite in terms of SO 3- no more than 4% by weight;
• mica - no more than 2% by weight;
• halogen compounds (halite, sylvin, etc.), including water-soluble chlorides, in terms of chlorine ion - not more than 0.15% by weight;
• coal - no more than 1% by weight;
• organic impurities (humic acids) - less than the amount that gives the sodium hydroxide solution (colorimetric test according to) a color corresponding to the color of the standard or darker than this color. The use of sand that does not meet this requirement is allowed only after receiving positive results of tests of sand in concrete or mortar for durability characteristics.

The permissible content of zeolite, graphite, oil shale is established on the basis of studies of the effect of sand on the durability of concrete or mortar.

End of document