Blocks made of cellular concrete GOST 21520 89. The ratio of types of blocks with an average density of concrete

1.2.1.1, 1.2.1.5, 3.4

5. REPUBLICATION. December 2003

This standard applies to wall small blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative humidity of indoor air of not more than 75% and in a non-aggressive environment.

In rooms with an air humidity of more than 60%, the inner surface of the outer 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 for 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 manufacture blocks of other sizes at the request of the consumer, agreed with the design organization. 2. The ratio of types of blocks with an average density of concrete is given in the appendix. 3. The thickness of the blocks for masonry with glue can be, if necessary, equal to the thickness of the blocks used for masonry with mortar.

1.1.3. When ordering, the symbolic designation of blocks should consist of the designation of the type of block, class (grade) of concrete in terms of compressive strength, grade in average density, grade in frost resistance and category.

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

I-B2,5D500F35-2

The same, type V block, compressive strength class B5, average 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 the manufacture of blocks must comply with the requirements GOST 25485.

1.2.1.2. Classes (grades) of concrete in terms of compressive strength and grades of concrete in average density should not be lower than class (grade) in strength B1.5 (M25) and grades in average density not higher than D1200.

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

1.2.1.5. The values ​​of shrinkage during drying, as well as the thermal conductivity of concrete blocks, should not exceed the values ​​\u200b\u200bspecified in GOST 25485.

1.2.1.6. Release humidity of concrete blocks should not exceed, % by weight:

25 - based on sand;

35 - "" ash and other production waste.

1.2.1.7. Concrete grades for frost resistance should be, depending on the mode of their operation and the estimated winter temperatures of the outdoor air in the construction areas, not less than:

F25 - for blocks of external walls;

F15 - "" internal "

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

table 2

Compressive strength class of concrete, not less than

________________
* The compressive strength ratings refer to non-autoclaved concrete blocks only.

1.2.2. The values ​​of deviations of geometric parameters and appearance indicators should not exceed the limit values ​​indicated in Table 3.

Table 3

The name of the deviation of the geometric parameter	Maximum deviation of blocks, mm, for masonry category
	on glue	on solution
Deviations from linear dimensions
Deviations for:
Length, thickness
Deviation from a rectangular shape (diagonal length difference)
Curvature of faces and edges
Damage to corners and ribs
Damage:
No more than two corners per block depth
Ribs on one block with a total length of not more than twice the length of the longitudinal rib and depth

Notes:

1. Damage to corners and ribs is not considered to be defects having a depth: for the 1st category - up to 3 mm, the 2nd - up to 5 mm and the 3rd - 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 that differ in grades of concrete in terms of average 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 a package of numbers indicating the average density of concrete blocks and their compressive strength class. For blocks with a concrete grade in 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 the batch have a concrete grade of average density D600 and a compressive strength class of B2.5, then the numbers are applied to the blocks

6-2,5

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

1.3.3. Each package must be marked "Keep away from moisture" on 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 5% of the lot in total.

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

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

2.5. Blocks are accepted according to the data of acceptance and periodic control.

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

Control of blocks in terms of frost resistance, thermal conductivity and shrinkage during drying is carried out before the start of mass production, when the technology or quality of materials changes, but at least once a year - in terms of thermal conductivity and shrinkage during drying and once every 6 months - in terms of frost resistance .

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

2.7. For the control check of 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, the control check of the blocks is carried out:

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

In terms of frost resistance - at least six blocks from the middle part of one array;

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 of different arrays;

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

By shrinkage during drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, a second check is carried out for this indicator of the double number of samples of the controlled lot.

In case of unsatisfactory results of the re-check in terms of geometric parameters, the acceptance of blocks is carried out individually.

Upon receipt of reduced results of a re-test in terms of strength and frost resistance, a batch of blocks is accepted according to the obtained indicators during control.

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

The possibility of using accepted blocks that do not correspond to those specified in terms of strength, average density, release moisture and frost resistance is established by the design organization.

2.9. Blocks in the package must be non-sticky and freely disassembled by hand.

2.10. Concrete strength control is carried out according to GOST 18105, and the 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;

Conditional designation of blocks;

The designation of this standard;

Number and date of issue of the quality document;

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

3. CONTROL METHODS

3.1. The dimensions, the difference in the lengths of the diagonals, the curvature of the faces and edges are checked according to GOST 13015.0 and GOST 26433.0.

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

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

** The document is not valid on the territory of the Russian Federation. Active 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. The control of the damage depth of the ribs and corners is carried out by measuring the perpendicular lowered from the top 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 edges of the blocks with 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:

Compressive strength - according to GOST 10180 ;

- average density - according to GOST 12730.1 ;

Frost resistance - according to GOST 25485 ;

Dry shrinkage - according to GOST 25485 ;

Thermal conductivity of concrete blocks - according to GOST 25485 ;

Release humidity - according to GOST 12730.2 and GOST 21718

4. TRANSPORT AND STORAGE

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

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

4.4. Blocks should be stored sorted by types, categories, strength classes, grades by average density and stacked in stacks no more than 2.5 m high. Blocks should be protected from moisture.

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

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

APP (recommended). RATIO OF TYPES OF BLOCKS 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 text of the document
prepared by Kodeks JSC and verified against:
official publication
Moscow: IPK Standards Publishing House, 2004

GOST 21520-89

Group G33

INTERSTATE STANDARD

BLOCKS FROM CELLULAR CONCRETE WALL SMALL

Specifications

Small-sized wall blocks of cellular concrete. Specifications

MKS 91.080.40
OKP 58 3000

Introduction date 1990-01-01

INFORMATION DATA

1. DEVELOPED by the Research, Design and Technological Institute of Concrete and Reinforced Concrete (NIIZhB) of the State Construction Committee of the USSR, the Central Research and Design and Experimental Institute of Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after V.A. .Kucherenko) Gosstroy of the USSR, Research Institute of Building Physics (NIISF) Gosstroy of the USSR

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

2. APPROVED AND INTRODUCED BY Decree of the State Construction Committee of the USSR of 30.03.89 N 58

3. REPLACE GOST 21520-76

4. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

	Item number
	1.2.1.3, 2.10
	1.2.1.1, 1.2.1.5, 3.4

5. REPUBLICATION. December 2003

This standard applies to wall small blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative humidity of indoor air of not more than 75% and in a non-aggressive environment.

In rooms with an air humidity of more than 60%, the inner surface of the outer 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 for 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 manufacture blocks of other sizes at the request of the consumer, agreed with the design organization. 2. The ratio of types of blocks with an average density of concrete is given in the appendix. 3. The thickness of the blocks for masonry with glue can be, if necessary, equal to the thickness of the blocks used for masonry with mortar.

1.1.3. When ordering, the symbolic designation of blocks should consist of the designation of the type of block, class (grade) of concrete in terms of compressive strength, grade in average density, grade in frost resistance and category.

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

I-B2,5D500F35-2

The same, type V block, compressive strength class B5, average 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 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 average density should not be lower than class (grade) in strength B1.5 (M25) and grades in average density not higher than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required one, assigned in accordance with GOST 18105, depending on the normalized strength of concrete specified in the order, and on the indicators of the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned in accordance with GOST 27005, depending on the normalized average density specified in the order, and on the indicators of 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, should not exceed the values ​​\u200b\u200bspecified in GOST 25485.

1.2.1.6. Release humidity of concrete blocks should not exceed, % by weight:

25 - based on sand;

35 - "" ash and other production waste.

1.2.1.7. Concrete grades for frost resistance should be, depending on the mode of their operation and the estimated winter temperatures of the outdoor air in the construction areas, not less than:

F25 - for blocks of external walls;

F15 - "" internal "

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

table 2

Concrete grade by average density
Compressive strength class of concrete, not less than

________________
* The compressive strength ratings refer to non-autoclaved concrete blocks only.

1.2.2. The values ​​of deviations of geometric parameters and appearance indicators should not exceed the limit values ​​indicated in Table 3.

Table 3

The name of the deviation of the geometric parameter	Maximum deviation of blocks, mm, for masonry category
	on glue	on solution
Deviations from linear dimensions
Deviations for:
Length, thickness
Deviation from a rectangular shape (diagonal length difference)
Curvature of faces and edges
Damage to corners and ribs
Damage:
No more than two corners per block depth
Ribs on one block with a total length of not more than twice the length of the longitudinal rib and depth

Notes:

1. Damage to corners and ribs is not considered to be defects having a depth: for the 1st category - up to 3 mm, the 2nd - up to 5 mm and the 3rd - 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 that differ in grades of concrete in terms of average 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 a package of numbers indicating the average density of concrete blocks and their compressive strength class. For blocks with a concrete grade in 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 the batch have a concrete grade of average density D600 and a compressive strength class of B2.5, then the numbers are applied to the blocks

6-2,5

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

1.3.3. Each packed place must be marked with the sign "Keep away from 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 Table 3 should not exceed 5% of the lot in total.

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

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

2.5. Blocks are accepted according to the data of acceptance and periodic control.

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

Control of blocks in terms of frost resistance, thermal conductivity and shrinkage during drying is carried out before the start of mass production, when the technology or quality of materials changes, but at least once a year - in terms of thermal conductivity and shrinkage during drying and once every 6 months - in terms of frost resistance .

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

2.7. For the control check of 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, the control check of the blocks is carried out:

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

In terms of frost resistance - at least six blocks from the middle part of one array;

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 of different arrays;

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

By shrinkage during drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, a second check is carried out for this indicator of the double number of samples of the controlled lot.

In case of unsatisfactory results of the re-check in terms of geometric parameters, the acceptance of blocks is carried out individually.

Upon receipt of reduced results of a re-test in terms of strength and frost resistance, a batch of blocks is accepted according to the obtained indicators during control.

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

The possibility of using accepted blocks that do not correspond to those specified in terms of strength, average density, release moisture and frost resistance is established by the design organization.

2.9. Blocks in the package must be non-sticky and freely disassembled by hand.

2.10. Concrete strength control is carried out according to GOST 18105, and medium 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;

Conditional designation of blocks;

The designation of this standard;

Number and date of issue of the quality document;

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

3. CONTROL METHODS

3.1. The dimensions, the difference in the lengths of the diagonals, the curvature of the faces and edges are checked in accordance with GOST 13015.0 and GOST 26433.0.

3.2. All measuring instruments used must be at least 2nd class of 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 is in force on the territory of the Russian Federation **.

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

3.3. The control of the damage depth of the ribs and corners is carried out by measuring the perpendicular lowered from the top 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 edges of the blocks with a depth gauge according to

GOST 21520– 89

INTERSTATE STANDARD

BLOCKS FROM CELLULAR CONCRETE WALL SMALL

Specifications

GOST 21520– 89

Small-sized wall blocks of cellular cancrete. Specifications

Date of introduction: 01.01.1990

This standard applies to wall small blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative humidity of indoor air of not more than 75% and in a non-aggressive environment.

In rooms with an air humidity of more than 60%, the inner surface of the outer 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 for technological documentation approved in the prescribed manner.

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

Table 1

Types	Masonry dimensions, mm
	on solution			on glue
	height	thickness	length	height	thickness	length
Notes: 1. It is allowed to manufacture blocks of other sizes at the request of the consumer, agreed with the design organization. 2. The ratio of types of blocks with an average density of concrete is given in the appendix. 3. The thickness of the blocks for masonry with glue can be, if necessary, equal to the thickness of the blocks used for masonry with mortar.

1.1.3. When ordering, the symbolic designation of blocks should consist of the designation of the type of block, class (grade) of concrete in terms of compressive strength, grade in average density, grade in frost resistance and category.

Symbol example type I block, compressive strength class B2.5, average density grade D500, frost resistance grade F35 and category 2:

I-B2,5D500F35-2

The same, block type V, compressive strength class B5, average 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 average density should not be lower than class (grade) in strength B1.5 (M25) and grades in average density not more than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required one, assigned in accordance with GOST 18105, depending on the normalized strength of concrete specified in the order, and on the indicators of the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned in accordance with GOST 27005, depending on the normalized average density specified in the order, and on the indicators of 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, should not exceed the values ​​\u200b\u200bspecified in GOST 25485.

1.2.1.6. Release humidity of concrete blocks should not exceed (by weight) more than,%:

25 - based on sand;

35 - based on ash and other production waste.

1.2.1.7. Concrete grades for frost resistance should be, depending on the mode of their operation and the estimated winter temperatures of the outdoor air in the construction areas, not less than:

F25 - for blocks of external walls;

F15 - for blocks of internal walls.

1.2.1.8. The ratio of concrete grades for average density with concrete classes for compressive strength is given in table. 2.

Table 2

Concrete class according to strength on compression, not less

––––––––––

* The compressive strength ratings refer to non-autoclaved concrete blocks only.

1.2.2 . The values ​​of deviations of geometric parameters and indicators of appearance should not exceed the limit values ​​indicated in Table. 3.

Table 3

The name of the deviation of the geometric parameter	Limit deviations, mm blocks for masonry category
	category 1	category 2	category 3
	on glue	on solution
Deviations from linear dimensions
Deviations for: length, thickness
Deviation from a rectangular shape (diagonal length difference)	2	4	6
Curvature of faces and edges	1	3	5
Damage to corners and ribs
corners (no more than two) on one block with a depth	5	10	15
ribs on one block with a total length of not more than twice the length of the longitudinal rib and a depth	5	10	15
Notes: 1. Damage to corners and ribs is not considered to be defects having a depth: for the 1st category - up to 3 mm, the 2nd - up to 5 mm and the 3rd - 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 that differ in grades of concrete in terms of average 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 their compressive strength class. For blocks with a concrete grade in 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 the batch have a concrete grade for average density D600 and a compressive strength class of B2.5, then numbers are applied to the blocks

6 – 2,5

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

10 –7,5

1.3.3. Each packed place must be marked with the 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 Table. 3 shall not exceed 5% of the lot in total.

2.3. The number of blocks with damage to the corners and ribs exceeding those indicated in Table. 3 shall not exceed 5% of the lot in total.

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

2.5. Blocks are accepted according to the data of acceptance and periodic control.

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

Control of blocks for frost resistance, thermal conductivity and shrinkage during drying is carried out before the start of mass production, when the technology or quality of materials changes, but at least once a year - in terms of thermal conductivity and shrinkage during drying and once every 6 months - in terms of frost resistance.

2.6. The consumer has the right to conduct a control check of the compliance of the blocks specified in the order with the requirements of this standard, using the product control procedure specified in paragraphs. 2.7 and 2.8.

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

With a vertical 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 different arrays;

In terms of frost resistance - at least six blocks from the middle part of one array;

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 arrays;

In terms of frost resistance - at least three blocks from the middle row, and with a two-row cutting of the upper row of one array;

By shrinkage during drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, a second check is carried out for this indicator of the double number of samples of the controlled lot.

In case of unsatisfactory results of the re-check in terms of geometric parameters, the acceptance of blocks is carried out individually.

Upon receipt of reduced results of a re-test in terms of strength and frost resistance, a batch of blocks is accepted according to the results obtained during control.

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

The possibility of using accepted blocks that do not correspond to those specified in terms of strength, average density, release moisture and frost resistance is established by the design organization.

2.9. Blocks in the package must be non-sticky and freely disassembled by hand.

2.10. Concrete strength control is carried out according to GOST 18105, and medium 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;

Conditional designation of blocks;

The designation of this standard;

Number and date of issue of the quality document;

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

Price (for retail products).

3. CONTROL METHODS

3.1. The dimensions, the difference in the lengths of the diagonals, the curvature of the faces and edges are checked by methods in accordance with GOST 13015, GOST 26433.0 and GOST 26433.1.

3.2. All measuring instruments used must be at least 2nd class of 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. The control of the damage depth of the ribs and corners is carried out by measuring the perpendicular, lowered from the top 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 edges of the blocks with 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:

Compressive strength - according to GOST 10180;

Average density - according to GOST 12730.1;

Frost resistance - according to GOST 25485;

Shrinkage during drying - according to GOST 25485;

Thermal conductivity of concrete blocks - according to GOST 7076;

Release humidity - according to GOST 12730.2, GOST 21718.

Scheme for measuring the depth of damagecorners and edges of blocks

4. TRANSPORT 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 a 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 transport of any kind in accordance with the requirements of GOST 9238 and the Specifications for loading and securing cargo.

4.3. It is forbidden to load blocks in bulk and unload them by dropping them.

4.4. Blocks should be stored sorted by types, categories, strength classes, grades by average density and stacked in stacks no more than 2.5 m high. Blocks should be protected from moisture.

RATIO OF TYPES OF BLOCKS WITH AVERAGE DENSITY OF CONCRETE

block type	Concrete grade by average density
	D500 D600 D700	D800	D900	D1000	D1100	D1200
I	x	-	-	-	-	-
II		x
III			x
IV		-	-
V		x	x	x	x	x
VI						-
VII					-
VIII					x
IX
X						x
Note. The "-" sign means that it is not recommended to use.

INFORMATION DATA

1. DEVELOPED by the Research, Design and Technological Institute of Concrete and Reinforced Concrete (NIIZhB) of the State Construction Committee of the USSR, the Central Research and Design and Experimental Institute of Complex Problems of Building Structures and Structures named after V. A. Kucherenko (TsNIISK named after Kucherenko) of the State Construction Committee USSR, Research Institute of Building Physics (NIISF) Gosstroy of the USSR

State Construction Committee of the Estonian SSR

PERFORMERS A. M. Krokhin, Ph.D. tech. sciences (topic leader); R. L. Serykh, Dr. Tech. sciences; I. M. Drobyashchenko, Ph.D. tech. sciences; N. I. Levin, Ph.D. tech. sciences; L. I. Ostrat, Ph.D. tech. sciences; V. G. Gagarin, Ph.D. tech. sciences; A. I. Ananiev, Ph.D. tech. sciences; T. A. Ukhova, Ph.D. tech. sciences; R. M. Koltovskaya; I. N. Nagornyak

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

2. APPROVED AND INTRODUCED BY Decree of the State Construction Committee of the USSR dated March 30, 1989 No. 58

3. REPLACE GOST 21520-76

4. DATE OF VERIFICATION 1996

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

	Number of paragraph, subparagraph		Number of paragraph, subparagraph
GOST 8.326-89		GOST 14192-96
		GOST 18105-86
GOST 3560-73		GOST 18343-80
GOST 9238-83		GOST 20259-80
GOST 10180-90		GOST 21718-84
GOST 12730.1-78		GOST 25485-89	1.2.1.1; 1.2.1.2; 1.2.1.5; 3.4
GOST 12730.2-83		GOST 26433.0-85
GOST 13015.0-83		GOST 27005-86
GOST 13015.1-81

Failure to comply with the standard is punishable by law!

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 relegated to the background, familiar to everyone, brick and reinforced concrete panels. One of the leading positions in the list is occupied by blocks of 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 concretes. Due to the large number of artificially created pores (about 85%), it has excellent thermal insulation and strength characteristics with a relatively small mass. One of the positive factors that determine 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 course of construction activities. The erection of walls is carried out with the help of a special glue that does not create the so-called cold bridges.

Aerated concrete blocks are a great alternative to brickwork

The positive properties of cellular composites include:

• High strength characteristics, allowing the use of blocks for the construction of load-bearing walls in buildings up to 15 meters high.
• The possibility of performing thermal insulation of equipment, the surface of which is heated up to 700 ⁰С.
• The absence of the possibility of mold and rot, reproduction of fungi.
• Frost resistance, allowing the use of the material in climatic zones with low temperatures.
• Moisture resistance, which is achieved due to the closed pore structure.
• High environmental friendliness, which removes questions about the negative impact of building materials on humans.
• Durability, thanks to which you can not worry about the reliability of the object being built.
• Fire safety, as the material is not subject to combustion.
• High flexibility, which makes it easy to process products and give them a non-standard configuration.
• Reducing the effort on the foundation of the building due to the use of products that have a small mass, despite the significant dimensions.
• No need for special lifting equipment to lift the composite to the work site, which significantly reduces the construction time.
• Increased level of sound insulation associated with high sound absorption due to the cellular structure of the array.

Varieties of cellular concrete

To ensure all the positive properties, the production of blocks must be carried out in strict accordance with GOST under the number 21520, developed and published in the 89th year.

This material has a number of advantages, due 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 of the chemical reaction of the reagent with the main 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, technical documentation has been developed that requires compliance with the technological process during production. It regulates the permissible deviations of geometric parameters, the rules for the installation of finished products.

Scope of application

The wide scope of application of cellular composites is due to high thermal insulation characteristics. This allows them to be used for tasks such as:

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

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

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

Main controlled parameters

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

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

Scope of use

Blocks of cellular concrete wall are used in the construction of external walls, as well as internal partitions. The construction of objects in places with high humidity exceeding 75% is not recommended. The use of cellular materials with air humidity above 60% is possible, provided that their inner surface is covered with a vapor barrier layer.

It is very profitable and economically justified to build private-type buildings from cellular materials: cottages, offices, garden houses, warehouses, garages. When erecting load-bearing walls, it is allowed to use if the height of the building does not exceed 15 meters, with self-supporting walls - not exceeding 30 meters in height.

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

Technical specifications

The requirements of the regulatory document clearly stipulate the dimensions and various features. The standard breaks down wall products made of cellular composites into ten types.

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

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

The document provides for the possibility of fixing products made of cellular concrete with glue. At the same time, the geometric dimensions for each type differ from those indicated above and are represented by the following size range:

• length is 298, 398, 598 mm;
• width changes as follows: 195, 245.295 mm;
• the height of the composites is 98, 198, 298 mm.

It is allowed, in accordance with the applications of consumers, to produce blocks that differ in size. For products of the same type, its thickness when fixed with adhesive is less than the width allowed for installation with mortar.

This standard applies to wall small blocks made of cellular concrete.

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

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

When using different grades of concrete, it is not recommended to violate the ratios provided for by the regulatory document.

Marking features

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

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

Materials and concrete for the manufacture of blocks must comply with the requirements

Consider the specific marking of the block II-B7.5D800F35-3 and decipher its parameters:

• II - characterizes the standard size.
• B7.5 - deciphers the product class by its strength and ability to perceive compressive loads.
• D800 - corresponds to the value of 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 has a difference in the average density of the concrete composition and strength class must be marked with a paint that cannot be washed off without fail.

When products are placed in a special container or package, marking should be carried out 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 having an average density of D800, characterized by a compressive strength class of B7.5.

The presence of this information allows customers to clearly determine the type of purchased products, and the manufacturer to store and ship them in accordance with the standard size indicated on the package.

General characteristics

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

Cellular concrete blocks are considered one of the best building materials; they can be used to build both residential and utility rooms.

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

• F25 if the product is applied to the outer walls of the building.
• F15 when using composites indoors.

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

• the value of D500 corresponds to the following classes of concrete B1.5-B3.5;
• 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 blocks made of cellular composite is associated with deviations in their geometric parameters. There are 3 different categories of cellular blocks for which the document provides dimensional tolerance values:

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

Aerated concrete blocks of the D600 and D500 grades are successfully used as a heat-insulating and structural material

• Products of the 2nd category are installed on the mortar and are distinguished by an increased tolerance in length and thickness equal to ±4 mm, as well as a height of ±3 mm. The allowable diagonal difference for them is 4 millimeters.
• The product of the 3rd group, intended for fixation with a solution, is 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 squareness deviation has a maximum value of 6 millimeters.

In addition to the geometric dimensions of the product and the deviation from the rectangular configuration, the normative document indicates the possible depth of damage to the edges 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

The highest degree of accuracy is characterized by products of the first category, which have a minimum dimensional deviation.

Product acceptance and quality control

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

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

The document regulates the sample size for control, upon detection of defects. The volume of a batch of controlled products during repeated tests is doubled. Any batch of goods is accompanied by a document confirming its quality, indicating in it data about the organization that manufactured the specified products.

Warehousing and delivery specifics

Quality indicators and safety of products are associated not only with the features of the manufacturing process. Important features of storage and transportation. The document prescribes the delivery of products on special pallets or containers, to ensure its immobility.

It is forbidden to ship in bulk and dump by overturning the body. Storage should be carried out with a breakdown by standard sizes and categories.

Conclusion

These are the main provisions of the standard for wall small composites used for the manufacture of block structures in 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 site site
Education and work experience: Higher technical education. Experience in various industries and construction sites - 12 years, of which 8 years - abroad.
Other skills and abilities: Has the 4th group of the admission on electrical safety. Performing calculations using large data arrays.

GOST 21520-89

UDC 691.327 - 412:006.354

Group G33

INTERSTATE STANDARD

BLOCKS FROM CELLULAR CONCRETE WALL SMALL

Technicalterms

Small-sized wall blocks of cellular concrete.

Specifications

MKS 91.080.40

Date of introduction 01.01.90

INFORMATION DATA

1. DEVELOPED by the Research, Design and Technological Institute of Concrete and Reinforced Concrete (NIIZhB) of the State Construction Committee of the USSR, the Central Research and Design and Experimental Institute of Complex Problems of Building Structures and Structures named after V. A. Kucherenko (TsNIISK named after Kucherenko) of the State Construction Committee USSR, Research Institute of Building Physics (NIISF) Gosstroy of the USSR

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

2. APPROVED AND INTRODUCED BY Decree of the State Construction Committee of the USSR dated March 30, 1989 No. 58

3. REPLACE GOST 21520-76

4. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

	Item number		Item number
GOST 8.326-89
		GOST 18105-86
GOST 9238-83		GOST 18343-80			GOST 20259-80
GOST 12730.1-78
GOST 12730.2-78		GOST 25485-89	1.2.1.1; 1.2.1.5; 3.4
GOST 13015-83		GOST 26433.0-85
GOST 13015.1-81		GOST 27005-86

5. reissue. December 2003

This standard applies to wall small blocks made of cellular concrete (hereinafter referred to as blocks) intended for laying external, internal walls and partitions of buildings with a relative humidity of indoor air of not more than 75% and in a non-aggressive environment.

In rooms with an air humidity of more than 60%, the inner surface of the outer 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 for technological documentation approved in the prescribed manner.

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

Table 1

block type	Block size, mm, for masonry
	on solution

Notes:

1. It is allowed to manufacture blocks of other sizes at the request of the consumer, agreed with the design organization.

2. The ratio of types of blocks with an average density of concrete is given in the appendix.

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

1.1.3. When ordering, the symbolic designation of blocks should consist of the designation of the type of block, class (grade) of concrete in terms of compressive strength, grade in average density, grade in frost resistance and category.

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

I-AT2.5D500F35-2

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

V- B5 D900 F75-1

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 average density should not be lower than class (grade) in strength B1.5 (M25) and grades in average density not more than D1200.

1.2.1.3. The actual strength of concrete must correspond to the required one, assigned in accordance with GOST 18105, depending on the normalized strength of concrete specified in the order, and on the indicators of the actual uniformity of concrete strength.

1.2.1.4. The actual average density of concrete must correspond to the required one, assigned in accordance with GOST 27005, depending on the normalized average density specified in the order, and on the indicators of 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, should not exceed the values ​​\u200b\u200bspecified in GOST 25485.

1.2.1.6. Release humidity of concrete blocks should not exceed, % by weight:

25 - based on sand;

35 - based on ash and other production waste.

1.2.1.7. Concrete grades for frost resistance should be, depending on the mode of their operation and the estimated winter temperatures of the outdoor air in the construction areas, not less than:

F25 - for blocks of external walls;

F15 - for blocks of internal walls.

1.2.1.8. The ratio of concrete grades for average density with concrete classes for compressive strength is given in table. 2.

table 2

________________

* The compressive strength ratings refer to non-autoclaved concrete blocks only.

1.2.2. The values ​​of deviations of geometric parameters and indicators of appearance should not exceed the limit values ​​indicated in Table. 3.

Table 3

The name of the deviation of the geometric parameter	Maximum deviation, mm, masonry blocks category
		on solution
Deviations from linear dimensions
Deviations for:
Length, thickness
Deviation from a rectangular shape (diagonal length difference)
Curvature of faces and edges
Damage to corners and ribs
Damage:
Corners (no more than two) on one block deep
Ribs on one block with a total length of not more than twice the length of the longitudinal rib and depth

Notes:

1. Damage to corners and ribs is not considered to be defects having a depth: for the 1st category - up to 3 mm, the 2nd - up to 5 mm and the 3rd - 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 that differ in grades of concrete in terms of average density and strength classes should be marked with indelible paint.

1.3.2. The 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 their compressive strength class. For blocks with a concrete grade in 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 the batch have a concrete grade of average density D600 and a compressive strength class of B2.5, then the numbers are applied to the blocks

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

1.3.3. Each packed place must be marked with the sign "Keep away from 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 Table. 3 shall not exceed 5% of the lot in total.

2.3. The number of blocks with damage to the corners and ribs exceeding those indicated in Table. 3 shall not exceed 5% of the lot in total.

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

2.5. Blocks are accepted according to the data of acceptance and periodic control.

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

Control of blocks in terms of frost resistance, thermal conductivity and shrinkage during drying is carried out before the start of mass production, when the technology or quality of materials changes, but at least once a year - in terms of thermal conductivity and shrinkage during drying and once every 6 months - in terms of frost resistance .

2.6. The consumer has the right to conduct a control check of the compliance of the blocks specified in the order with the requirements of this standard, using the product control procedure specified in paragraphs. 2.7 and 2.8.

2.7. For the control check of 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, the control check of the blocks is carried out:

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

In terms of frost resistance - at least six blocks from the middle part of one array;

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 arrays;

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

By shrinkage during drying - one block at a time.

2.8. If the control results are unsatisfactory for at least one of the indicators, a second check is carried out for this indicator of the double number of samples of the controlled lot.

In case of unsatisfactory results of the re-check in terms of geometric parameters, the acceptance of blocks is carried out individually.

Upon receipt of reduced results of re-testing in terms of strength and frost resistance, a batch of blocks is accepted according to the obtained indicators during control.

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

The possibility of using accepted blocks that do not correspond to those specified in terms of strength, average density, release moisture and frost resistance is established by the design organization.

2.9. Blocks in the package must be non-sticky and freely disassembled by hand.

2.10. Concrete strength control is carried out according to GOST 18105, and medium 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;

Conditional designation of blocks;

The designation of this standard;

Number and date of issue of the quality document;

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

price (for products supplied to retailers).

3. CONTROL METHODS

3.1. The dimensions, the difference in the lengths of the diagonals, the curvature of the faces and edges are checked by methods in accordance with GOST 13015.0 and GOST 26433.0.

3.2. All measuring instruments used must be at least 2nd class of 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 is in force on the territory of the Russian Federation.

3.3. The control of the damage depth of the ribs and corners is carried out by measuring the perpendicular, lowered from the top 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 edges of the blocks with 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:

Compressive strength - according to GOST 10180;

Average density - according to GOST 12730.1;

Frost resistance - according to GOST 25485;

Shrinkage during drying - according to GOST 25485;

Thermal conductivity of concrete blocks - according to GOST 25485;

Release humidity - according to GOST 12730.2 and GOST 21718.

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

4. TRANSPORT 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 a 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 transport of any kind in accordance with the requirements of GOST 9238 and the "Technical conditions for loading and securing cargo."

4.4. Blocks should be stored sorted by types, categories, strength classes, grades by average density and stacked in stacks no more than 2.5 m high. Blocks should be protected from moisture.

RATIO OF TYPES OF BLOCKS 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.

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