GOST 21520 89 blocks made of cellular concrete. Failure to comply with the standard is punishable by law

GOST 21520-89

UDC 691.327 - 412:006.354

Group Zh33

INTERSTATE STANDARD

SMALL WALL BLOCKS FROM CELLULAR CONCRETE

Technicalconditions

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 USSR State Construction Committee, the Central Research and Design and Experimental Institute of Complex Problems building structures and structures named after V. A. Kucherenko (TsNIISK named after Kucherenko) of the USSR State Construction Committee, Scientific Research Institute of Construction Physics (NIISF) of the USSR State Construction Committee

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

2. APPROVED AND ENTERED INTO EFFECT by State Resolution construction committee USSR dated March 30, 1989 No. 58

3. INSTEAD GOST 21520-76

4. REFERENCE REGULATIVE 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 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

1.1. Main parameters and dimensions

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

1.1.2. The types and sizes of blocks must correspond to those indicated in the 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. Correlation of block types with medium density concrete 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 block type, 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-IN2.5D500F35-2

The same, block type V, compressive strength class B5, medium 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 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 drying shrinkage values, as well as the thermal conductivity of concrete blocks, should 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 - 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

________________

* 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 the table. 3.

Table 3

Name of deviation of geometric parameter	Maximum deviation, mm, of blocks for masonry category

		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:
Corners (no more than two) on one block deep
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. 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 with opposite sides container or package with numbers indicating the average density of the concrete 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

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

2.1. 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, should 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, should 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 humidity 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 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, 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 from 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 establishes project 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;

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;

price (for products supplied to retail trade).

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*.

________________

* In the territory Russian Federation PR 50.2.009-94 applies.

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.

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.

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.

GOST 21520-89

Group Zh33

INTERSTATE STANDARD

SMALL WALL BLOCKS FROM CELLULAR CONCRETE

Specifications

Small-sized wall blocks of cellular concrete. Specifications

MKS 91.080.40
OKP 58 3000

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, the Central Research and Design-Experimental Institute for Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after V.A. .Kucherenko) of the USSR State Construction Committee, the Research Institute of Construction Physics (NIISF) of the USSR State Construction Committee

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

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

3. INSTEAD GOST 21520-76

4. REFERENCE REGULATIVE 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 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 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.

An example of a symbol for a block of 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 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.

1.2.1.5. 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:

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 - "" 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 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 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 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 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.

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 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;

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 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 is controlled 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 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 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 (Resolution of the Government of the Russian Federation of April 6, 2011 N 246). - Database manufacturer's note.

1.2.1.1, 1.2.1.5, 3.4

5. REPUBLICATION. December 2003

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 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.

An example of a symbol for a block of 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.

1.2.1.3. 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.

1.2.1.8. 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. The deviation values of geometric parameters and appearance indicators 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.

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.