GOST 21520-89 “Small cellular concrete wall blocks”

Construction technologies are improving day by day. This concerns, first of all, the materials used in the construction of buildings. for various purposes. Artificial composites are slowly relegating the familiar brick and reinforced concrete panels to the background. One of the leading positions in the list is occupied by blocks from cellular concrete. What is this material, the production of which is carried out in accordance with the requirements of the standard?

General concepts

Cellular concrete belongs to the group of lightweight concrete. Thanks to the large number of artificially created pores (approximately 85%), it has excellent thermal insulation and strength characteristics with a relatively small mass. One of the positive factors determining the priority position of cellular materials in the general list is the correct geometric shape. Dimensional deviations do not exceed 2 mm, which greatly facilitates the progress of construction activities. The walls are erected using a special glue that does not create so-called cold bridges.

Cellular concrete blocks are an excellent alternative to brickwork

The positive properties of cellular composites include:

• High strength characteristics allowing the use of blocks for construction load-bearing walls in buildings up to 15 meters high.
• Possibility of thermal insulation of equipment whose surface heats up to 700 ⁰C.
• No possibility of mold and rot formation, fungal growth.
• Frost resistance, allowing the material to be used in climatic zones with low temperatures.
• Moisture resistance, which is achieved due to the closed pore structure.
• Highly environmentally friendly, which eliminates questions about negative impact building materials per person.
• Durability, thanks to which you don’t have to worry about the reliability of the object being built.
• Fire safety, since the material is not subject to combustion.
• High flexibility, which makes it easy to process products and give them non-standard configurations.
• Reduction of forces on the foundation of the building due to the use of products with low mass, despite their significant dimensions.
• There is no need for special lifting equipment to lift the composite to the work site, which significantly reduces the time required for construction activities.
• Increased level of sound insulation associated with high sound absorption due to the cellular structure of the array.

Types of cellular concrete

To ensure all the positive properties, the production of blocks must be carried out in strict accordance with GOST number 21520, developed and published in 1989.

This material has a number of advantages, thanks to which it is widely used for the construction of residential buildings.

Three main types of cellular concrete blocks are used in construction:

• foam concrete, obtained by mixing specially prepared foam with cement mortar;
• aerated concrete, the formation of pores in which occurs as a result chemical reaction reagent with basic composition;
• gas silicate, the pores in which are obtained due to the reaction of lime, crushed sand, water with gas-forming components.

For these types of concrete it has been developed technical documentation, requiring compliance technological process in production. It regulates the permissible deviations of geometric parameters and the rules for installing finished products.

Scope of application

The wide range of applications of cellular composites is due to the high thermal insulation characteristics. This allows you to use them when performing tasks such as:

• Insulation of wall and ceiling reinforced concrete floors.
• Thermal insulation attic spaces, which is especially relevant during the construction of buildings with an attic, suggesting the possibility year-round residence in them.
• Creation of thermal pads in the construction of multilayer structures. IN in this case ensures comfortable temperature regime premises, without sudden fluctuations.
• Providing thermal insulation for equipment with elevated surface temperatures.
• Creation of a thermal barrier when laying pipelines.
• Construction of walls of private houses and small buildings.

In order to obtain cellular concrete mechanically, a cement-based solution is made to which sand and water are added

Let us consider in more detail what requirements for cellular concrete wall blocks are specified in the current regulatory documents.

Main controlled parameters

The current GOST for small wall composites stipulates the following points:

• scope of application;
• technical features;
• specifics of acceptance control;
• testing methodology;
• storage and transportation conditions.

Area of ​​use

Cellular concrete wall blocks are used in the construction external walls, and internal partitions. It is not recommended to construct objects in areas with high humidity exceeding 75%. The use of cellular materials at air humidity above 60% is possible, provided that they are inner surface will be covered with a vapor barrier layer.

It is very profitable and economically justifiable to construct private buildings from cellular materials: cottages, offices, garden houses, storage facilities, garages. When constructing load-bearing walls, use is allowed if the height of the building does not exceed 15 meters, with self-supporting walls– not exceeding 30 meters in height.

The use of wall blocks made of cellular concrete during construction ensures high fire safety, tightness of walls, floors, and partitions

Technical specifications

In requirements normative document dimensions and various features. The standard breaks down wall products made from cellular composites into ten types.

According to the types of composite, as well as the possibility of laying with mortar, their geometric dimensions vary as follows:

• The length of the composites is standardized and represents a standard range from 288 to 588 mm.
• The width is represented by a range of sizes in the range of 88-288 mm.
• Thickness is 200, 250, 300 mm.

The document provides for the possibility of fixing products made of cellular concrete using glue. In this case, the geometric dimensions for each type differ from those indicated above and are represented by the following standard size range:

• length is 298, 398, 598 mm;
• width varies as follows: 195, 245,295 mm;
• The height of the composites is 98, 198, 298 mm.

It is allowed, in accordance with consumer requests, to produce blocks of different sizes. For products of the same type, their thickness when fixed with adhesive is less than the permissible width when installed using mortar.

This standard applies to small wall blocks made of cellular concrete

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The mandatory annex to the standard specifies which grade of concrete can be used for the production of:

• Compositions marked D500, D600 and D700 are used for composites 1 to 10.
• The D800 mixture corresponds to 2, 3, and 5-10 types.
• Solution D900 is acceptable for types 3 and 5-10.
• Concrete with a density of D1000 can be used for 5-10 types of products.
• The composition of D1100 corresponds to 5.6, as well as 8-10 classes.
• Medium density concrete D1200 is suitable for types 5 and 10.

Using various brands concrete, it is not recommended to violate the ratios provided for in the regulatory document.

Marking features

When manufacturing a product, its order code must include the following information:

• product type marking;
• brand or classification concrete composition characterizing its strength;
• digital index indicating the specific gravity of the concrete mass;
• designation of the array's resistance to negative temperatures;
• category.

Materials and concrete for making blocks must meet the requirements

Let's look at the specific markings of block II-B7.5D800F35-3 and decipher its parameters:

• II – characterizes the standard size.
• B7.5 - deciphers the class of the product according to its strength and ability to withstand compressive loads.
• D800 – corresponds to the average density of the concrete composition.
• F35 – indicates the degree of frost resistance.
• 3 – index characterizing the designation of the category.

Any batch of goods that differs in the average density of the concrete composition and strength class must be marked with paint that cannot be washed off.

When placing products in a special container or package, marking must be done on two opposite sides of the package. For example, if the designation 8-7.5 is applied, then it means that the products in this batch are made from concrete with an average density of D800 and are characterized by a compressive strength class of B7.5.

The presence of this information allows customers to clearly determine the type of product being purchased, and the manufacturer to store and ship it in accordance with the standard size indicated on the packaging.

General characteristics

The strength characteristics of the concrete used should not be lower than B1.5, which corresponds to grade M25, as well as a composition whose specific gravity is designated D1200.

Cellular concrete blocks considered one of the best building materials, with their help you can build both residential and commercial premises

The document regulates the criteria for the resistance of blocks to the effects of negative temperatures, which corresponds to the following marking:

• F25, if the product is used for external walls of a building.
• F15 when using composites indoors.

Dependence of marking of concrete composition on average specific gravity and classification of solutions, according to their hardness, are given in the table of the regulatory document as follows:

• the following concrete classes B1.5-B3.5 correspond to the D500 value;
• D600 and D700 – B2-B5;
• D800 and D900 – B2.5-B7.5;
• D1000 – B5, B7.5;
• D1100 – B7.5, B10;
• D1200 – B10, B12.5.

Tolerance indicators

The quality of cellular composite blocks is associated with deviations of their geometric parameters. There are 3 various categories cellular blocks for which the document provides values maximum deviations sizes:

• The first category, intended for installation with glue, is characterized by a deviation in the length and thickness of the product of ±2 millimeters, as well as in height of ±1 millimeter. In this case, the tolerance for the difference in diagonal length, characterizing the compliance of the block with a rectangular configuration, is a maximum of 2 millimeters.

Aerated concrete blocks of grades D600 and D500 are successfully used as thermal insulation and structural material

• Products of the 2nd category are installed on the mortar and have an increased tolerance for length and thickness equal to ±4 millimeters, as well as height ±3 millimeters. The permissible difference in diagonals for them is 4 millimeters.
• Products of the 3rd group, intended for fixation using a solution, are characterized by the maximum tolerance value. They are ±5 millimeters for the height, and ±6 millimeters for the length and thickness of the block. The deviation from squareness has a maximum value of 6 millimeters.

Besides geometric dimensions products and deviations from the rectangular configuration, the regulatory document indicates the possible depth of damage to the ribs and corners of the block. It ranges from 5 to 15 mm depending on the product category.

Scheme for measuring the depth of damage to wall blocks

Products of the first category, which have minimal dimensional deviation, are characterized by the highest degree of accuracy.

Product acceptance and quality control

The standard obliges product manufacturers to accept products based on the results of acceptance inspection and periodic testing. During the acceptance control process, the following parameters are checked:

• dimensions;
• the ability of products to withstand compressive loads;
• specific gravity value;
• change in humidity.

The document regulates the sample size for monitoring if a defect is detected. The volume of the batch of controlled products is doubled during repeated testing. Any batch of goods is accompanied by a document confirming its quality, indicating in it information about the organization that manufactured the specified product.

Specifics of warehousing and delivery

The quality indicators and safety of products are associated not only with the features of the manufacturing process. The features of storage and transportation are also important. The document prescribes the delivery of products on special pallets or containers and ensure their immobility.

It is prohibited to ship in bulk or dump by tipping the body. Storage should be carried out by size and category.

Conclusion

These are the main provisions of the standard for small wall composites used for the manufacture of block structures during the construction of walls. Compliance with the requirements of the regulatory document guarantees the release of high-quality products that meet modern requirements.

On the site: Author and editor of articles on the website website
Education and work experience: Higher technical education. 12 years of experience in various industries and construction sites, 8 of which were abroad.
Other skills and abilities: Has the 4th group of electrical safety clearance. Perform calculations using large areas data.

1.2.1.1, 1.2.1.5, 3.4

5. REPUBLICATION. December 2003

This standard applies to small wall blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, interior walls and partitions of buildings with a relative indoor air humidity of no more than 75% and in a non-aggressive environment.

In rooms with air humidity of more than 60%, the inner surface of the external wall blocks must have a vapor barrier coating.

1. TECHNICAL REQUIREMENTS

1. TECHNICAL REQUIREMENTS

1.1. Main parameters and dimensions

1.1.1. Blocks should be manufactured in accordance with the requirements of this standard according to technological documentation approved in the prescribed manner.

1.1.2. The types and sizes of blocks must correspond to those indicated in Table 1.

Table 1

Block type	Block size, mm, for masonry
	on solution
Notes: 1. It is allowed to produce blocks of other sizes upon the customer’s order, agreed upon with the design organization. 2. The relationship between block types and average concrete density is given in the Appendix. 3. The thickness of the blocks for masonry with glue can, if necessary, be equal to the thickness of the blocks used for masonry with mortar.

1.1.3. The designation of blocks when ordering must consist of a designation of the type of block, class (grade) of concrete for compressive strength, grade for average density, grade for frost resistance and category.

Example symbol block type I, compressive strength class B2.5, medium density grade D500, frost resistance grade F35, category 2:

I-B2.5D500F35-2

The same, block type V, compressive strength class B5, medium density grade D900, frost resistance grade F75, category 1:

V-B5D900F75-1

1.2. Characteristics

1.2.1. Requirements for materials and concrete

1.2.1.1. Materials and concrete for making blocks must meet the requirements GOST 25485.

1.2.1.2. Classes (grades) of concrete in terms of compressive strength and grades of concrete in terms of average density must be no lower than class (grades) in terms of strength B1.5 (M25) and grades in terms of average density not higher than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required strength assigned by GOST 18105 depending on the standardized strength of concrete specified in the order, and on the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned according to GOST 27005 depending on the normalized average density specified in the order and on the actual uniformity of concrete density.

1.2.1.5. The values ​​of shrinkage during drying, as well as the thermal conductivity of concrete blocks, must not exceed the values ​​​​specified in GOST 25485.

1.2.1.6. The release moisture content of concrete blocks should not exceed, % by weight:

25 - sand-based;

35 - " " ash and other production waste.

1.2.1.7. Frost resistance grades of concrete should depend on their operating mode and design winter temperatures outdoor air in construction areas, not less than:

F25 - for external wall blocks;

F15 - "" internal "

1.2.1.8. The ratio of concrete grades by average density to concrete classes by compressive strength is given in Table 2.

table 2

Concrete class for compressive strength, not less

________________
* Class indicators for compressive strength refer only to blocks made of non-autoclaved concrete.

1.2.2. Deviation values ​​of geometric parameters and indicators appearance should not exceed the limits specified in Table 3.

Table 3

Name of deviation of geometric parameter	Maximum deviation of blocks, mm, for masonry category
	on glue	on solution
Deviations from linear dimensions
Deviations by:
Length, thickness
Deviation from rectangular shape (difference in lengths of diagonals)
Curvature of faces and edges
Damage to corners and ribs
Damage:
No more than two corners on one block of depth
Ribs on one block with a total length of no more than twice the length of the longitudinal rib and depth

Notes:

1. Damage to corners and ribs does not include defects that have a depth: for the 1st category - up to 3 mm, 2nd - up to 5 mm and 3rd - up to 10 mm.

2. Release of blocks of the 3rd category is allowed until 01/01/96

1.3. Marking

1.3.1. Batches of blocks that differ in concrete grades based on average density and strength classes should be marked with indelible paint.

1.3.2. Markings should be applied to at least two blocks on opposite sides of the container or package of numbers indicating the average concrete density of the blocks and their compressive strength class. For blocks with a concrete grade of average density from D500 to D900, one first digit of the number should be applied, from D1000 to D1200 - the first two digits of the number. For example, if the blocks in a batch have an average density concrete grade of D600 and a compressive strength class of B2.5, then numbers are applied to the blocks

6-2,5

For concrete grade of average density D1000 and compressive strength class B7.5, numbers are applied

1.3.3. Each packaged item must be marked with a "Keep away from moisture" sign. GOST 14192.

2. ACCEPTANCE

2.1. Acceptance of blocks - by GOST 13015.1 and this standard in batches.

2.2. The number of blocks with deviations from linear dimensions exceeding those indicated in Table 3 should not exceed a total of 5% of the batch.

2.3. The number of blocks with damage to corners and edges exceeding those indicated in Table 3 should not exceed a total of 5% of the batch.

2.4. The number of blocks with cracks crossing more than two faces, as well as blocks with cracks along four faces, should not total more than 5% of the lot.

2.5. Blocks are accepted according to acceptance and periodic inspection data.

Blocks are accepted based on the results of acceptance tests in terms of compressive strength, average density, release moisture content and geometric parameters.

Control of blocks in terms of frost resistance, thermal conductivity and drying shrinkage is carried out before the start of mass production, when technology or quality of materials changes, but not less often: once a year - in terms of thermal conductivity and drying shrinkage and once every 6 months - in terms of frost resistance .

2.6. The consumer has the right to carry out control check compliance of the units specified in the order with the requirements of this standard, using the control procedure specified in clauses 2.7 and 2.8.

2.7. To control check the blocks for compliance with the requirements of clause 1.2.2, at least 30 blocks are selected from the batch from the outer and inner rows of containers or stacks.

With a vertical cutting scheme, control check of the blocks is carried out:

In terms of average density, compressive strength and release moisture - for at least two blocks from different massifs;

In terms of frost resistance - no less than six blocks from the middle part of one massif;

At horizontal scheme cutting, control check of blocks is carried out:

In terms of average density, compressive strength and release moisture - at least two blocks from each layer of different massifs;

In terms of frost resistance - at least three blocks from the middle row, and in the case of two-row cutting - from the top row of one array;

According to shrinkage upon drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, double the number of samples of the controlled batch is re-checked for this indicator.

If the results of re-checking the geometric parameters are unsatisfactory, the blocks are accepted individually.

If lower results of re-testing in terms of strength and frost resistance are received, a batch of blocks is accepted according to the indicators obtained during control.

If values ​​for the average density of concrete are underestimated or overestimated by one grade, a batch of blocks is accepted according to the indicators obtained during control.

The possibility of using accepted blocks that do not meet the specified strength, average density, release humidity and frost resistance indicators is established by the design organization.

2.9. The blocks in the package must not be stuck together and can be easily disassembled by hand.

2.10. Concrete strength control is carried out according to GOST 18105, and average density - according to GOST 27005.

2.11. Each batch of blocks is accompanied by a quality document, which indicates:

Name and address of the manufacturer;

Symbol of blocks;

Designation of this standard;

Number and date of issue of the quality document;

Batch number, volume and/or number of units shipped.

3. CONTROL METHODS

3.1. Dimensions, difference in lengths of diagonals, curvature of edges and edges are checked by GOST 13015.0 And GOST 26433.0.

3.2. All measuring instruments used must be at least class 2 accuracy.

It is allowed to use special non-standardized measuring instruments that have passed metrological certification in accordance with the requirements GOST 8.326 *.
________________
* In the territory Russian Federation act PR 50.2.009-94 **.

** The document is not valid on the territory of the Russian Federation. Valid Regulations on the implementation of state metrological supervision(decree Government of the Russian Federation dated April 6, 2011 N 246). - Database manufacturer's note.

3.3. Control of the depth of damage to the ribs and corners is carried out by measuring the perpendicular lowered from the apex of the corner or from the edge to the conditional plane of the defect, in accordance with the scheme for measuring the depth of damage to the corners and ribs of the blocks using a depth gauge according to GOST 162.

3.4. Specifications blocks are controlled in accordance with the requirements of the following standards:

Compressive strength - according to GOST 10180 ;

- average density - according to GOST 12730.1 ;

Frost resistance - according to GOST 25485 ;

Drying shrinkage - according to GOST 25485 ;

Thermal conductivity of concrete blocks - according to GOST 25485 ;

Holiday humidity - according to GOST 12730.2 And GOST 21718

4. TRANSPORTATION AND STORAGE

4.1. Blocks are transported in containers by GOST 20259 or on pallets GOST 18343 with rigid fixation with shrink film or ligation with steel tape according to GOST 3560 or other fastening that ensures the immobility and safety of the blocks.

4.2. Transportation of blocks is carried out by any type of transport in accordance with the requirements GOST 9238 And "Technical conditions for loading and securing cargo".

4.4. Blocks must be stored sorted by type, category, strength class, grade by average density and stacked in stacks no more than 2.5 m high. Blocks must be protected from moisture.

Rice. Scheme for measuring the depth of damage to corners and edges of blocks

SCHEME FOR MEASURING THE DEPTH OF DAMAGE TO CORNERS AND RIBS OF BLOCKS

APP (recommended). RELATIONSHIP OF BLOCK TYPES WITH AVERAGE DENSITY OF CONCRETE

Block type	Concrete grade by average density
	D500, D600, D700

Note. The "-" sign means that concrete of this medium density is not recommended.

Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: IPK Standards Publishing House, 2004

Designation	GOST 21520-89
Title in Russian	Small cellular concrete wall blocks. Specifications
Title in English	Small-sized wall blocks of cellular concrete. Specifications
Effective date	01.01.1990
OKS	91.080.40
OKP code	583000
KGS code	Zh33
Index of the GRNTI rubricator	671131
Abstract (scope of application)	This standard applies to small wall blocks made of cellular concrete intended for laying external, internal walls and partitions of buildings with a relative indoor air humidity of no more than 75% and in a non-aggressive environment
Keywords	state building; masonry of external, internal walls and partitions of buildings;
Type of standard	Standards for products (services)
Designation of the replacement(s)	GOST 21520-76
Designation of the replacement part	GOST 31360-2007 regarding products made of autoclaved cellular concrete
Normative references to: GOST	GOST 8.326-78; GOST 162-80; GOST 3560-73; GOST 9238-83; GOST 10180-89; GOST 12730.1-78; GOST 12730.2-78; GOST 13015-75; GOST 13015.1-81; GOST 14192-77; GOST 18105-86; GOST 18343-80; GOST 20259-80; GOST 21718-84; GOST 25485-89; GOST 26433.0-85; GOST 27005-86
Document submitted by CIS organization	NIIZhB Gosstroy USSR
Rostekhregulirovaniya Department	50 - Ministry of Construction of the Russian Federation
MND developer	Russian Federation
Last edition date	01.12.2003
Change number(s)	reissue
Number of pages (original)	7
Organization - Developer	Research Institute for Reinforced Concrete Construction of the USSR State Construction Committee; TsNIISK them. V.A. Kucherenko of the USSR State Construction Committee; NIISF of the USSR State Construction Committee; State Construction Committee of the Estonian SSR
Status	Valid

GOST 21520-89

Group Zh33

STATE STANDARD OF THE USSR UNION

BLOCKS FROM CELLULAR CONCRETE

WALL SMALL

Specifications

Small-sized wall blocks of

cellular cancrete.

Date of introduction 1990-01-01

INFORMATION DATA

1. DEVELOPED by the Research, Design and Technological Institute of Concrete and Reinforced Concrete (NIIZhB) of the USSR State Construction Committee

Central Research and Design Experimental Institute complex problems building structures and structures named after V.A. Kucherenko (TsNIISK named after Kucherenko) of the USSR State Construction Committee

Research Institute of Building Physics (NIISF) of the USSR State Construction Committee

State Construction Committee of the ESSR

PERFORMERS

A.M. Krokhin, Candidate of Technical Sciences (topic leader); R.L. Serykh, Doctor of Technical Sciences; I.M.Drobyashchenko, Candidate of Technical Sciences; N.I.Levin, Ph.D. sciences; L.I.Ostrat, Candidate of Technical Sciences; V.G. Gagarin, Candidate of Technical Sciences; A.I.Ananyev, Candidate of Technical Sciences; T.A. Ukhova, Candidate of Technical Sciences; R.M.Koltovskaya; I.N.Nagornyak

2. INTRODUCED by the Research, Design and Technological Institute of Concrete and Reinforced Concrete (NIIZhB) of the USSR State Construction Committee

3. APPROVED AND ENTERED INTO EFFECT by Resolution of the State Construction Committee of the USSR dated March 30, 1989 N 58

4. INSTEAD GOST 21520-76

5. INSPECTION DATE 1996

6. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

Designation NTD, for which it is given	Item number, subparagraph	Designation NTD, for which it is given	Item number, subparagraph
GOST 8.326-78 GOST 3560-73 GOST 7076-87 GOST 9238-83 GOST 10180-89 GOST 12730.1-78 GOST 12730.2-78 GOST 13015-75		GOST 13015.1-81 GOST 14192-77 GOST 18105-86 GOST 18343-80 GOST 20259-80 GOST 21718-84 GOST 25485-89 GOST 26433.0-85 GOST 26433.1-89 GOST 27005-86	1.2.1.1;1.2.1.2;

This standard applies to small wall blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative indoor air humidity of no more than 75% and in a non-aggressive environment.

In rooms with air humidity of more than 60%, the inner surface of the external wall blocks must have a vapor barrier coating.

1. TECHNICAL REQUIREMENTS

1.1. Main parameters and dimensions

1.1.1. Blocks should be manufactured in accordance with the requirements of this standard according to technological documentation approved in the prescribed manner.

1.1.2. The types and sizes of blocks must correspond to those indicated in the table. 1.

Table 1

Mm

	Dimensions for masonry
	on solution
Notes: 1. It is allowed to produce blocks of other sizes upon the customer’s order, agreed upon with the design organization. 2. The relationship between block types and average concrete density is given in the Appendix. 3. The thickness of the blocks for masonry with glue can, if necessary, be equal to the thickness of the blocks used for masonry with mortar.

1.1.3. The designation of blocks when ordering must consist of a designation of the type of block, class (grade) of concrete for compressive strength, grade for average density, grade for frost resistance and category.

An example of a symbol for a block of type I, compressive strength class B2.5, medium density grade D500, frost resistance grade F35 and category 2:

The same, block type V, compressive strength class B5, medium density grade D900, frost resistance grade F75 and category 1:

1.2. Characteristics

1.2.1. Requirements for materials and concrete

1.2.1.1. Materials and concrete for the manufacture of blocks must comply with the requirements of GOST 25485.

1.2.1.2. Classes (grades) of concrete in terms of compressive strength and grades of concrete in terms of average density must be no lower than class (grades) in terms of strength B1.5 (M25) and grades in terms of average density not higher than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required strength, assigned according to GOST 18105, depending on the standardized strength of concrete specified in the order and on the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned according to GOST 27005, depending on the normalized average density specified in the order and on the actual uniformity of concrete density.

1.2.1.5. The values ​​of shrinkage during drying, as well as the thermal conductivity of concrete blocks, must not exceed the values ​​​​specified in GOST 25485.

1.2.1.6. The release moisture content of concrete blocks should not exceed (by weight) more than, %:

25 - sand-based;

35 - " " ash and other production waste.

1.2.1.7. The frost resistance grades of concrete should be, depending on their mode of operation and the estimated winter outside air temperatures in the construction areas, no less than:

F25 - for external wall blocks;

F15 - " " of internal walls.

1.2.1.8. The ratio of concrete grades by average density to concrete classes by compressive strength is given in Table. 2.

table 2

Concrete grade according to medium density
Concrete class according to compressive strength
no less

* Class indicators for compressive strength refer only to blocks made of non-autoclaved concrete.

1.2.2. The deviation values ​​of geometric parameters and appearance indicators should not exceed the limits specified in the table. 3.

Table 3

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INTERSTATE STANDARD

BLOCKS FROM CELLULAR CONCRETE
WALL SMALL

TECHNICAL CONDITIONS

IPC PUBLISHING HOUSE OF STANDARDS

Moscow

INTERSTATE STANDARD

Date of introduction 01/01/90

This standard applies to small wall blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative indoor air humidity of no more than 75% and in a non-aggressive environment.

In rooms with air humidity of more than 60%, the inner surface of the external wall blocks must have a vapor barrier coating.

1. TECHNICAL REQUIREMENTS

1.1. Main parameters and dimensions

1.1.1. Blocks should be manufactured in accordance with the requirements of this standard according to technological documentation approved in the prescribed manner.

1.1.2. The types and sizes of blocks must correspond to those indicated in the table. 1.

Table 1

	Dimensions for masonry
	on solution

Notes:

1. It is allowed to produce blocks of other sizes upon the customer’s order, agreed upon with the design organization.

2. The relationship between block types and average concrete density is given in the Appendix.

3. The thickness of the blocks for masonry with glue can, if necessary, be equal to the thickness of the blocks used for masonry with mortar.

1.1.3. The designation of blocks when ordering must consist of a designation of the type of block, class (grade) of concrete for compressive strength, grade for average density, grade for frost resistance and category.

An example of a symbol for a block of type I, compressive strength class B2.5, medium density grade D500, frost resistance grade F35 and category 2:

I-B2.5D500F35-2

The same type V, compressive strength class B5, medium density grade D900, frost resistance grade F75 and category 1.

V-B5D900F75-1

1.2. Characteristics

1.2.1. Requirements for materials and concrete

1.2.1.1. Materials and concrete for the manufacture of blocks must comply with the requirements of GOST 25485.

1.2.1.2. Classes (grades) of concrete in terms of compressive strength and grades of concrete in terms of average density must be no lower than class (grades) in terms of strength B1.5 (M25) and grades in terms of average density not higher than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required strength, assigned according to GOST 18105, depending on the standardized strength of concrete specified in the order and on the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned according to GOST 27005, depending on the normalized average density specified in the order and on the actual uniformity of concrete density.

1.2.1.5. The values ​​of drying shrinkage, as well as the thermal conductivity of concrete blocks, must not exceed the values ​​​​specified in GOST 25485.

1.2.1.6. The release moisture content of concrete blocks should not exceed (by weight) more than, %:

25 - sand-based;

35 - based on ash and other production waste.

1.2.1.7. The frost resistance grades of concrete should be, depending on their mode of operation and the estimated winter outside air temperatures in the construction areas, no less than:

F25 - for external wall blocks;

F15 - for internal wall blocks.

1.2.1.8. The ratio of concrete grades by average density to concrete classes by compressive strength is given in Table. 2.

table 2

Concrete grade by average density
Concrete class for compressive strength, not less

* Class indicators for compressive strength refer only to blocks made of non-autoclaved concrete.

1.2.2. The deviation values ​​of geometric parameters and appearance indicators should not exceed the limits specified in the table. 3.

Table 3

Name of deviation of geometric parameter	Prev. off
	Blocks for masonry with glue	Blocks for masonry on mortar
Deviations from linear dimensions
Deviations by:
Length, thickness
Deviation from rectangular shape (difference in lengths of diagonals)
Curvature of faces and edges
Damage to corners and ribs
Damage:
No more than two corners on one block of depth
Ribs on one block with a total length of no more than twice the length of the longitudinal rib and depth

Notes:

2. The release of blocks of the 3rd category is allowed until 01/01/96.

1.3. Marking

1.3.1. Batches of blocks differing in concrete grades for medium density and strength classes should be marked with indelible paint.

1.3.2. Marking should be applied to at least two blocks (on opposite sides of the container or package) with numbers indicating the average concrete density of the blocks and the compressive strength class. For blocks with a concrete grade of average density from D500 to D900, one first digit of the number should be applied, from D1000 to D1200 - the first two digits of the number, for example: if the blocks in a batch have a concrete grade of average density D600 and a compressive strength class of B2, 5, then numbers are applied to the blocks

For concrete grade of average density D1000 and compressive strength class B7.5, numbers are applied

1.3.3. Each packaged item must be marked with a “Keep away from moisture” sign in accordance with GOST 14192.

2. ACCEPTANCE

2.11. Each batch of blocks is accompanied by a quality document, which indicates:

Name and address of the manufacturer;

Symbol of blocks;

Designation of this standard;

Number and date of issue of the quality document;

Batch number, volume and/or number of units shipped;

3. CONTROL METHODS

3.1. Dimensions, difference in lengths of diagonals, curvature of edges and edges are checked using methods according to GOST 13015.0 and GOST 26433.0.

3.2. All measuring instruments used must be at least class 2 accuracy.

It is allowed to use special non-standardized measuring instruments that have passed metrological certification in accordance with the requirements of GOST 8.326 *.

* PR 50.2.009-94 applies on the territory of the Russian Federation.

3.3. Control of the depth of damage to the ribs and corners is carried out by measuring the perpendicular lowered from the apex of the corner or from the rib to the conditional plane of the defect, in accordance with the scheme for measuring the depth of damage to the corners and ribs of the blocks using a depth gauge according to GOST 162.

3.4. The technical characteristics of the blocks are controlled in accordance with the requirements of the following standards:

Thermal conductivity of concrete blocks - according to GOST 25485;

Scheme for measuring the depth of damage to corners and edges of blocks

4. TRANSPORTATION AND STORAGE

4.1. Blocks are transported in containers in accordance with GOST 20259 or on pallets in accordance with GOST 18343 with rigid fixation with shrink film or bandaging them with steel tape in accordance with GOST 3560 or other fastening that ensures the immobility and safety of the blocks.

4.2. Transportation of blocks is carried out by any type of transport in accordance with the requirements of GOST 9238 and “ Technical specifications loading and securing cargo."

4.4. Blocks must be stored sorted by type, category, strength class, grade by average density and stacked in stacks no more than 2.5 m high. Blocks must be protected from moisture.

State standard USSR GOST 21520-89

"SMALL WALL BLOCKS FROM CELLULAR CONCRETE. TECHNICAL CONDITIONS"

Small-sized wall blocks of cellular cancrete. Specifications

Instead of GOST 21520-76

This standard applies to small wall blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative indoor air humidity of no more than 75% and in a non-aggressive environment.

In rooms with air humidity of more than 60%, the inner surface of the external wall blocks must have a vapor barrier coating.

1. Technical requirements

1.1. Main parameters and dimensions

1.1.1. Blocks should be manufactured in accordance with the requirements of this standard according to technological documentation approved in the prescribed manner.

1.1.2. The types and sizes of blocks must correspond to those indicated in the table. 1.

Table 1

	Dimensions for masonry
	on solution

Notes:

1. It is allowed to produce blocks of other sizes upon the customer’s order, agreed upon with the design organization.

2. The relationship between block types and average concrete density is given in the Appendix.

3. The thickness of the blocks for masonry with glue can, if necessary, be equal to the thickness of the blocks used for masonry with mortar.

1.1.3. The designation of blocks when ordering must consist of a designation of the type of block, class (grade) of concrete for compressive strength, grade for average density, grade for frost resistance and category.

An example of a symbol for a block of type I, compressive strength class B2, 5, medium density grade D500, frost resistance grade F35 and category 2:

I - B2, 5D500F35-2

The same, block type V, compressive strength class B5, medium density grade D900, frost resistance grade F75 and category 1:

V - B5D900F75-1

1.2. Characteristics

1.2.1. Requirements for materials and concrete

1.2.1.1. Materials and concrete for the manufacture of blocks must comply with the requirements of GOST 25485.

1.2.1.2. Classes (grades) of concrete in terms of compressive strength and grades of concrete in terms of average density must be no lower than class (grades) in strength B1, 5 (M25) and grades in terms of average density no more than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required strength, assigned according to GOST 18105, depending on the standardized strength of concrete specified in the order and on the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned according to GOST 27005, depending on the normalized average density specified in the order and on the actual uniformity of concrete density.

1.2.1.5. The values ​​of shrinkage during drying, as well as the thermal conductivity of concrete blocks, must not exceed the values ​​​​specified in GOST 25485.

1.2.1.6. The release moisture content of concrete blocks should not exceed (by weight) more than, %:

1.2.1.7. The frost resistance grades of concrete should be, depending on their mode of operation and the estimated winter outside air temperatures in the construction areas, no less than:

1.2.1.8. The ratio of concrete grades by average density to concrete classes by compressive strength is given in Table. 2.

table 2

* Class indicators for compressive strength refer only to blocks made of non-autoclaved concrete.

1.2.2. The deviation values ​​of geometric parameters and appearance indicators should not exceed the limits specified in the table. 3.

Table 3

Notes:

1. Damage to corners and ribs does not include defects that have a depth: for category 1 - up to 3 mm, category 2 - up to 5 mm, category 3 - up to 10 mm.

2. The release of blocks of the 3rd category is allowed until 01/01/96.

1.3. Marking

1.3.1. Batches of blocks differing in concrete grades for medium density and strength classes should be marked with indelible paint.

1.3.2. Marking should be applied to at least two blocks (on opposite sides of the container or package) with numbers indicating the average concrete density of the blocks and the compressive strength class. For blocks with a concrete grade of average density from D500 to D900, one first digit of the number should be applied, from D1000 to D1200 - the first two digits of the number, for example: if the blocks in a batch have a concrete grade of average density D600 and a compressive strength class of B2, 5, then numbers are applied to the blocks

6 - 2, 5.

For concrete grade of average density D1000 and compressive strength class B7, 5, numbers are applied

10 - 7, 5.

1.3.3. Each packaged item must be marked with a sign “Afraid of moisture” in accordance with GOST 14192.

2. Acceptance

2.1. Acceptance of blocks - in accordance with GOST 13015.1 and this standard in batches.

2.2. The number of blocks with deviations from linear dimensions exceeding those indicated in the table. 3, must not exceed a total of 5% of the lot.

2.3. The number of blocks with damage to corners and edges exceeding those indicated in the table. 3, must not exceed a total of 5% of the lot.

2.4. The number of blocks with cracks crossing more than two faces, as well as blocks with cracks along four faces, should not total more than 5% of the lot.

2.5. Blocks are accepted according to acceptance and periodic inspection data.

Blocks are accepted based on the results of acceptance tests in terms of compressive strength, average density, release moisture content and geometric parameters.

Control of blocks for frost resistance, thermal conductivity and drying shrinkage is carried out before the start of mass production, when technology or quality of materials changes, but not less often: once a year - for thermal conductivity and drying shrinkage and once every 6 months. - in terms of frost resistance.

2.6. The consumer has the right to carry out a control check of the compliance of the units specified in the order with the requirements of this standard, using the procedure for monitoring products specified in paragraphs. 2.7 and 2.8.

2.7. To control check the blocks for compliance with the requirements of clause 1.2.2 of this standard, at least 30 blocks are selected from the outer and inner rows of containers or stacks from the batch.

With a vertical cutting scheme, control check of the blocks is carried out:

in terms of average density, compressive strength and release moisture - for at least two blocks from different massifs;

in terms of frost resistance - no less than six blocks from the middle part of one massif;

With a horizontal cutting scheme, the control check of the blocks is carried out:

in terms of average density, compressive strength and release moisture - at least two blocks from each layer from different massifs;

in terms of frost resistance - no less than three blocks from the middle row, and in the case of two-row cutting - the top row of one array;

according to shrinkage upon drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, double the number of samples of the controlled batch is re-checked for this indicator.

If the results of re-checking the geometric parameters are unsatisfactory, the blocks are accepted individually.

If lower results of re-testing in terms of strength and frost resistance are received, a batch of blocks is accepted based on the results obtained during control.

If the values ​​for the average density of concrete are underestimated or overestimated by one grade, a batch of blocks is accepted according to the indicators obtained during control.

The possibility of using accepted blocks that do not meet the specified strength, average density, release humidity and frost resistance indicators is established by the design organization.

2.9. The blocks in the package must not be stuck together and can be easily disassembled by hand.

2.10. Concrete strength is controlled according to GOST 18105, and average density is controlled according to GOST 27005.

2.11. Each batch of blocks is accompanied by a quality document, which indicates:

name and address of the manufacturer;

block designation;

designation of this standard;

number and date of issue of the quality document;

batch number, volume and/or number of units shipped;

price (for products supplied to retail).

3. Control methods

3.1. Dimensions, difference in lengths of diagonals, curvature of edges and edges are checked using methods according to GOST 13015, GOST 26433.0 and GOST 26433.1.

3.2. All measuring instruments used must be at least class 2 accuracy.

It is allowed to use special non-standardized measuring instruments that have passed metrological certification in accordance with the requirements of GOST 8.326.

3.3. Control of the depth of damage to the ribs and corners is carried out by measuring the perpendicular lowered from the apex of the corner or from the edge to the conditional plane of the defect, in accordance with the scheme for measuring the depth of damage to the corners and ribs of the blocks using a depth gauge according to GOST 162.

3.4. The technical characteristics of the blocks are controlled in accordance with the requirements of the following standards:

4. Transportation and storage

4.1. Blocks are transported in containers in accordance with GOST 20259 or on pallets in accordance with GOST 18343 with rigid fixation with shrink film or bandaging them with steel tape in accordance with GOST 3560 or other fastening that ensures the immobility and safety of the blocks.

4.2. Transportation of blocks is carried out by any type of transport in accordance with the requirements of GOST 9238 and Technical conditions for loading and securing cargo.

4.4. Blocks should be stored sorted by type, category, strength class, grade by average density and stacked in stacks no more than 2.5 m high. Blocks must be protected from moisture.

Scheme for measuring the depth of damage to corners and edges of blocks

The ratio of block types to average concrete density

	Concrete grade by average density

Note. The "-" sign means that use is not recommended.