GOST R 56387-2015

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

DRY CONSTRUCTION MIXTURES WITH CEMENT BINDER

Specifications

Dry-mix cement based adhesives for tiles. Specifications

OKS 91.100.15
OKP 57 4550

Introduction date 2015-11-01

Foreword

1 DEVELOPED by the Non-Commercial Partnership "Union of Producers of Dry Building Mixes" (NP "SPSSS") with the participation of the Federal State Budgetary Educational Institution of Higher Professional Education "Moscow State Civil Engineering University" (MGSU), the Federal State Budgetary Educational Institution of Higher Professional Education "Saint Petersburg State University of Architecture and Civil Engineering (SPbGASU)

2 INTRODUCED by the Technical Committee for Standardization TC 465 "Construction"

3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology of April 9, 2015 N 247-st

4 This standard takes into account the main regulatory provisions of the following European regional standards:

EN 12004:2007 "Adhesives for tiles - Requirements, evaluation of conformity, classification and designation", NEQ);
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* Access to international and foreign documents mentioned in the text can be obtained by contacting the User Support Service. - Database manufacturer's note.

EH 1308:2007 Adhesives for tiles - Determination of slip (NEQ);

EN 1346:2007 "Adhesives for tiles - Determination of open time", NEQ;

EH 1347:2007 "Adhesives for tiles - Determination of wetting capability" (NEQ);

EN 1348:2007 "Adhesives for tiles - Determination of tensile adhesion strength for cementitious adhesives", NEQ);

EN 12002:2008 "Adhesives for tiles - Determination of transverse deformation for cementitious adhesives and grouts", NEQ

5 INTRODUCED FOR THE FIRST TIME

The rules for the application of this standard are set out in GOST R 1.0-2012 (section 8). Information about changes to this standard is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the next issue of the monthly information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (www.gost.ru)

Introduction

The object of standardization of this standard are dry building adhesive mixtures on a cement binder.

Adhesive mixtures are widely represented in the construction market of dry mixtures of the Russian Federation, each participant of which offers a range of adhesives from three to eight items. This standard was developed taking into account the requirements of European regional standards for adhesive mixtures and unified with them in terms of classification, acceptance rules and test methods.

This standard was developed for the purpose of regulatory provision of manufacturers of dry mixes in the Russian Federation with technical requirements and test methods for their products, which make it possible to obtain results similar to those in the EU countries for a comparative assessment of the construction and technical properties of adhesives in scientific, technical and economic cooperation.

1 area of use

This standard applies to dry building adhesive mixtures (hereinafter referred to as adhesive mixtures) made on a cement binder or mixed (complex) mineral binders based on Portland cement clinker and / or high-aluminate cement, containing polymer additives and used when facing with slabs or tiles of walls and floor coverings inside and outside buildings.

This standard establishes technical requirements for mixtures, acceptance rules, methods for characterization, requirements for the transportation and storage of mixtures.

2 Normative references

This standard uses normative references to the following standards:

GOST 4.233-86 System of product quality indicators. Construction. Building solutions. Nomenclature of indicators

GOST 8.579-2002 State system for ensuring the uniformity of measurements. Requirements for the quantity of packaged goods in packages of any kind during their production, packaging, sale and import

GOST 166-89 (ISO 3599-76) Calipers. Specifications

GOST 310.4-81 Cements. Methods for determining the ultimate strength in bending and compression

GOST 427-75 Measuring metal rulers. Specifications

GOST 5802-86 Building mortars. Test Methods

GOST 8735-88 Sand for construction work. Test Methods

GOST 14192-96 Marking of goods

GOST 30108-94 Building materials and products. Determination of specific effective activity of natural radionuclides

GOST 31189-2015 Dry building mixes. Classification

GOST 31356-2007 Dry building mixes based on cement binder. Test Methods

GOST 31357-2007 Dry building mixes based on cement binder. General specifications

Note - When using this standard, it is advisable to check the validity of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If an undated referenced reference standard has been replaced, it is recommended that the current version of that standard be used, taking into account any changes made to that version. If the reference standard to which the dated reference is given is replaced, then it is recommended to use the version of this standard with the year of approval (acceptance) indicated above. If, after the adoption of this standard, a change is made to the referenced standard to which a dated reference is given, affecting the provision to which the reference is given, then this provision is recommended to be applied without taking into account this change. If the reference standard is canceled without replacement, then the provision in which the reference to it is given is recommended to be applied in the part that does not affect this reference.

3 Terms and definitions

This standard uses the terms according to GOST 31189, GOST 31357, as well as the following terms with the corresponding definitions:

3.1 notched trowel: A toothed tool that allows you to create a layer of mortar mixture in the form of grooves of the same thickness on the base.

3.2 holding time after preparation: The period of time after mixing the mortar required to achieve readiness for laying.

3.3 open time: The maximum period of time after applying a layer of mortar mixture of a given adhesion strength to the base on the base, during which it is allowed to lay facing tiles on the applied mortar mixture.

3.4 wetting ability: The ability of a mortar layer treated with a notched trowel to wet the facing tiles.

3.5 slip: Gravity displacement of tiles or slabs laid on a notched trowel layer of mortar applied to a vertical or inclined surface.

3.6 viability: The maximum period of time during which a freshly prepared mortar mixture (after additional mixing without adding water) retains its technological properties.

3.7 adhesive strength (adhesion): Breaking stress at which the facing tile breaks away from the base.

4 Technical requirements

4.1 Adhesive mixtures must comply with the requirements of this standard and be produced according to the technological documentation approved by the manufacturer.

4.2 The properties of adhesive mixtures are characterized by the quality indicators of mixtures in a dry state, freshly prepared mixtures ready for use (hereinafter referred to as mortar mixtures), and hardened solutions.

4.2.1 The main indicators of the quality of adhesive mixtures in a dry state are:

- humidity;

- the largest grain size of the filler;

- the content of grains of the largest size.

4.2.2 The main indicators of the quality of mortar mixtures are:

- water holding capacity;

- resistance to slipping;

- average density.

4.2.3 The main indicators of the quality of hardened mortars are:

- the strength of the adhesive bond (adhesion) after exposure to an air-dry environment;

- the strength of the adhesive bond (adhesion) after exposure to the aquatic environment;

- the strength of the adhesive bond (adhesion) after exposure to high temperatures;

- adhesive bond strength (adhesion) after cyclic freezing and thawing;

- open time.

4.2.4 For adhesive mixtures, additional declared quality indicators can be established: wetting ability, transverse deformation, increased open time, and others in accordance with GOST 4.233 or the terms of the contract.

4.2* Adhesive mixtures are divided into the following classes:
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* The numbering corresponds to the original. - Database manufacturer's note.

- C0 - used for laying tiles with normal water absorption (at least 5% by weight) only for interior work;

- C1 - used to perform internal and external work and meet the minimum standardized requirements;

- С2 - used for internal and external works and corresponding to increased requirements;

- F - fast-hardening adhesive mixtures;

- T - mixtures with increased slip resistance;

- E - mixtures with increased open time;

S1 - elastic adhesive mixtures;

- S2 - highly elastic adhesive mixtures.

4.3 The symbol for adhesive mixtures should consist of the name of the mixture in accordance with GOST 31189, the designation of the class in accordance with 4.2, the values of the main quality indicators (if necessary) and the designation of this standard.

An example of a symbol for a cement-based adhesive mixture designed for interior and exterior use, meeting increased requirements, with increased slip resistance, extended open time and highly elastic:

Dry building adhesive mix C2 TE S2, GOST R 56387-2015

It is allowed to add additional information to the symbol of the adhesive mixture to ensure complete identification of the adhesive mixture.

4.4 Requirements for adhesive mixtures in a dry state

4.4.1 Moisture content of adhesive mixtures should not exceed 0.30% by weight.

4.4.2 The largest grain size of the adhesive mixture should not exceed 0.63 mm.

The content of grains larger than 0.63 mm in the adhesive mixture should not exceed 0.50%.

4.4.3 The specific effective activity of natural radionuclides of adhesive mixtures should not exceed the limit values established by GOST 30108.

4.5 Requirements for adhesive mortars

4.5.1 The water-holding capacity of ready-to-use adhesive mortars must be at least 98%.

4.5.2 The resistance to slip of adhesive mixtures is characterized by the value of displacement under the action of gravity of facing tiles laid on a vertical or inclined surface.

For adhesive mixtures of class T, the displacement value should be no more than 0.5 mm, for mixtures of other classes - no more than 0.7 mm.

4.5.3 Wetting ability of adhesive mixtures is characterized by the time during which the mortar mixture wets the facing tile. The wetting ability of adhesive mixtures must be at least 20 minutes, for class F adhesive mixtures - at least 10 minutes, for class E adhesive mixtures - at least 30 minutes.

4.5.4 The average density of adhesive mortar mixtures is set by the manufacturer at the request of the consumer.

4.6 Requirements for hardened adhesive solutions

4.6.1 The strength of the adhesive joint, depending on the conditions for the use of adhesive mixtures, must correspond to that given in Table 1.

Table 1 - Requirements for adhesive mixtures of various classes


Name of indicator	Value, MPa for class

The strength of the adhesive bond after exposure to an air-dry environment for 28 days
The strength of the adhesive bond after exposure to the aquatic environment
Adhesive bond strength after exposure to high temperatures
Adhesive strength after cyclic freezing and thawing

4.6.2 The strength of the adhesive bond with the base fast-hardening adhesives of class F after exposure to an air-dry environment for 6 hours should be at least 0.5 MPa.

The strength of the adhesive bond with the base of adhesives of classes T, E, S1 and S2 must be at least as given in table 1 for mixtures of classes C1 and C2.

4.6.3 Open time to achieve the strength of the adhesive bond after exposure to an air-dry environment of at least 0.5 MPa when gluing tiles should be for adhesives of the class:

- C0 and F - when gluing tiles after 10 minutes;

- C1 and C2 - when gluing tiles after 20 minutes;

- E - when gluing tiles after 30 minutes.

4.6.4 The transverse deformation of class S1 adhesives must be at least 2.5 mm, class S2 - at least 5 mm.

4.7 Requirements for materials used for the manufacture of dry adhesive mixtures

The materials used for the preparation of dry adhesive mixtures must comply with the requirements of GOST 31357 and regulatory or technical documents for these materials.

4.8 Packaging and labeling

4.8.1 Adhesive mixtures are packed in polyethylene film bags, multilayer paper bags made of kraft paper or with a polyethylene liner (packing unit). The mass of the dry mixture in bags should not exceed 8 kg, in bags - 50 kg. Permissible deviation of the mass of the dry mixture in one packaging unit - according to GOST 8.579.

Adhesive mixtures are allowed to be packed in big bags.

Packaging should protect the dry adhesive mixture from moisture. Violation of the integrity of the packaging is not allowed.

4.8.2 Marking should be applied to each packaging unit. The marking must be clear, not allowing any other interpretation regarding the properties of the adhesive mixture. The marking is applied with indelible paint directly to the packaging unit or a label glued to the packaging.

4.8.3 Each packaging unit must be marked with a handling sign "Keep away from moisture" in accordance with GOST 14192.

4.8.4 The marking must contain:

Name and/or trademark and address of the manufacturer;

- date of manufacture (month, year);

- the mass of the mixture in the packaging unit, kg;

- shelf life, months;

- brief instructions for the use of the adhesive mixture, indicating the volume of water required to obtain the mortar mixture of the required mobility, in liters per kilogram.

If necessary, the marking may contain additional data to ensure complete identification of the adhesive mixture.

4.8.5 Transport marking - according to GOST 14192.

5 Safety and environmental requirements

5.1 Adhesive mixtures are non-flammable, fire- and explosion-proof materials.

5.2 Sanitary and radiation safety of adhesive mixtures is established on the basis of the sanitary and epidemiological conclusion of the authorized bodies of state sanitary supervision and evaluated by the safety of mixtures or their components.

The safety of the mineral components of mixtures (cement binder, fillers, pigments) is evaluated by the content of radioactive substances, the safety of chemical additives in mixtures - by the sanitary and hygienic characteristics of additives.

5.3 Adhesive mixtures should not release harmful chemicals into the environment in amounts exceeding the maximum allowable concentrations (MPC) approved by the sanitary authorities.

5.4 It is forbidden to dump adhesive mixtures, as well as waste from washing equipment into sanitary waters and sewers.

6 Acceptance rules

6.1 Adhesive mixtures must be accepted by the technical control of the manufacturer. Mixtures are dispensed and taken by weight.

6.2 Adhesive mixtures are accepted in batches. For a batch of a mixture, the amount of a mixture of the same class and composition, made from the same materials, according to the same technology, is taken.

The batch volume of the adhesive mixture is set at least one shift and not more than one daily output of the mixer.

6.3 The quality of adhesive mixtures is confirmed by acceptance control, which includes acceptance and periodic tests.

For testing, at least five packaging units are selected from each batch of the mixture by random selection.

6.4 During acceptance tests of each batch of adhesive mixture, the following is determined:

- for dry mixes - humidity and grain composition;

- for mortar mixtures - water-retaining capacity, slip resistance and wetting ability.

A batch of the mixture is accepted if the results of acceptance tests for all indicators comply with the requirements of this standard.

In case of unsatisfactory results of acceptance tests for at least one indicator, repeated tests are carried out on a double amount of the mixture taken from the same batch. The retest results are final and apply to the entire batch.

6.5 Periodic tests determine:

- the strength of the adhesive bond after exposure to an air-dry environment for 28 days and the average density - at least once a month;

- the strength of the adhesive joint after exposure to the aquatic environment - within the time agreed with the consumer, but at least once a month;

- adhesive bond strength after exposure at high temperatures, adhesive bond strength after cyclic freezing and thawing, open time, transverse deformation - once every three months.

Periodic tests are also carried out when changing the quality or type of starting materials, the composition of the mixtures and / or the technology of their manufacture.

The results of periodic tests apply to all supplied batches of adhesive mixtures until the next periodic tests are carried out.

6.6 Sanitary and radiation-hygienic assessment of adhesive mixtures is confirmed by the presence of a sanitary-epidemiological conclusion of the authorized bodies of state sanitary supervision, which must be renewed after its expiration date or when the quality of the starting materials and the composition of the mixtures change.

6.7 Radiation-hygienic assessment of adhesive mixtures may be carried out on the basis of passport data of the supplier of raw mineral materials.

In the absence of the supplier's data on the content of natural radionuclides in the source materials, the manufacturer of adhesive mixtures determines the content of natural radionuclides in the materials and/or in the mixture at least once a year, and at each change of supplier.

6.8 The consumer has the right to conduct a control check of the quality of adhesive mixtures in accordance with the requirements and methods established in this standard.

6.9 Each batch of adhesive mixture must be accompanied by a quality document indicating:

- name of the manufacturer;

- symbol of the adhesive mixture according to 4.3;

- batch number;

- number and date of issue of the quality document;

- batch volume in kilograms (tons);

- values of the main quality indicators;

- specific effective activity of natural radionuclides;

- designation of this standard.

In export-import operations, the content of the quality document is specified in the contract for the supply of the mixture.

7 Test methods

7.1 Sampling of point samples of adhesive mixtures for testing, preparation of combined and laboratory samples is carried out in accordance with GOST 31356.

7.2 Humidity, the largest aggregate grain size and the content of the largest grain size in adhesive mixtures are determined according to GOST 8735.

The average density is determined according to GOST 5802.

7.3 The water-holding capacity of mortar mixtures is determined according to GOST 31356.

7.4 Slip resistance is determined by the method given in Annex A.

7.5 Wetting ability is determined by the method given in Appendix B.

7.6 The strength of the adhesive bond (adhesion) after exposure to an air-dry environment, in an aqueous environment, after exposure to high temperatures, cyclic freezing and thawing and open time is determined by the method given in Appendix B.

7.7 The transverse deformation is determined by the method given in Appendix D.

7.8 The specific effective activity of natural radionuclides is determined according to GOST 30108 or accepted according to the document on the quality of the supplier of materials used for the manufacture of adhesive mixtures.

8 Transport and storage

8.1 Transport

8.1.1 Packaged adhesive mixtures are transported in overpacks by road, rail and other modes of transport in accordance with the transportation rules applicable to a specific type of transport and the manufacturer's instructions.

Transportation of adhesive mixtures in bulk is not allowed.

8.1.2 The means of transportation of adhesive mixtures used must exclude the possibility of atmospheric precipitation getting into them, and also ensure the protection of the package from mechanical damage and integrity violations.

8.2 Storage

8.2.1 Adhesive mixtures should be stored in a packaged form, avoiding moisture and ensuring the safety of the package, in covered dry warehouses.

8.2.2 Guaranteed shelf life of packaged adhesive mixtures when stored in accordance with 8.2.1 is 12 months from the date of manufacture.

At the end of the shelf life, the mixture should be checked for compliance with the requirements of this standard. In case of compliance with the requirements of this standard, the adhesive mixture can be used for its intended purpose.

Annex A (mandatory). Method for determining slip resistance

Annex A
(mandatory)

A.1 Means of testing

Concrete slab according to GOST 31356.

Unglazed dry-pressed ceramic tile with water absorption less than 0.5% by weight, with a flat adhesive surface, face dimensions [(100±1)(100±1)] mm, weight (200±1) g.

Protective tape 25 mm wide.

Notched trowel with teeth dimensions 6x6 mm and distance between tooth centers 12 mm.

Stops made of stainless steel with dimensions [(25±0.5)(25±0.5)(10±0.5)] mm.

Cargo weighing 5 kg with cross-sectional dimensions [(100±1)(100±1)] mm.

Caliper according to GOST 166.

Metal ruler according to GOST 427.

Clamps.

A.2 Preparation for testing

All materials tested are kept for at least 24 h under normal conditions. As normal conditions (normal climate) take temperature (20 ± 2) ° C, relative humidity (60 ± 10)%, air circulation speed in the test area is less than 0.2 m / s.

GOST 31356.

A.3 Testing

metal ruler 1 (Figure A.1) are clamped to the top edge of the concrete slab 6 so that the bottom edge, after it has been placed in a vertical position, runs horizontally.

1 - ruler; 2 - protective tape; 3 - stops; 4 - ceramic tile; 5 - mortar mixture; 6 - concrete slab

Figure A.1 - Scheme for testing the adhesive mixture for slip

A protective tape is glued under the ruler 2 25 mm wide. A mortar mixture is applied to the concrete slab with a trowel in two layers. 5 : the first layer is 1-2 mm thick, the second layer is 6-8 mm thick so that it covers the lower edge of the protective tape. When applying the mortar mixture, the trowel is held at an angle of 60 ° to the surface of the plate and parallel to the ruler.

The mortar mixture is smoothed with a notched trowel perpendicular to the ruler, after which the protective tape is removed. Two stops 3 25 mm wide is applied to the ruler 1 as shown in Figure A.1. Two minutes later, ceramic tiles are applied to the stops 4 , as shown in figure A.1, and press it with a weight of mass 5 kg. Measure the distance between the ruler and the tile with a caliper at three points with an accuracy of ± 0.1 mm.

After (30 ± 5) s, the load and stops are removed, the concrete slab is carefully placed in a vertical position. After (20 ± 2) minutes, the distance between the ruler and the tile is again measured with a caliper at the same points with an accuracy of ± 0.1 mm. The maximum sliding of the tile under the action of its own mass is determined as the difference between the readings of the caliper.

Annex B (mandatory). Method for determining wetting ability

Annex B
(mandatory)

B.1 Means of testing

Glass plates [(50±1)(50±1)(6±0.5)] mm with ground edge.

Concrete slab according to GOST 31356.

A 2 kg load with a cross-sectional area not exceeding [(50±1)(50±1)] mm.

B.2 Preparation for testing

The preparation of the mortar mixture is carried out in accordance with the requirements of GOST 31356.

B.3 Testing

On a concrete slab 1 (Figure B.1) a mortar mixture is applied with a trowel in two layers: the first layer is 1-2 mm thick, the second is 6-8 mm thick.

1 - concrete slab (base); 2 - furrows of the mortar mixture formed by a notched trowel; 3 - glass plate

Figure B.1 - Scheme for testing the adhesive mixture for wetting ability

The layer of mortar mixture is smoothed perpendicular to the upper side face of the concrete slab with a notched trowel, holding it at an angle of 60° to the surface of the slab.

Glass plates are placed on the mortar layer 3 0, 10, 20 and 30 minutes after its application (see Figure B.1). Each plate is pressed by 30 with a load of 2 kg. Glass plates are placed on the layer of the mortar mixture so that its two opposite edges are parallel to the grooves of the mortar mixture. 2 .

After removing the load, the glass plates are carefully lifted and visually assessed as a percentage of the total area of the plate, the area of its surface wetted with the mortar mixture.

Three glass plates are used for one test.

B.4 Processing of test results

In the laboratory journal for each time interval (0, 10, 20 and 30 min) enter the arithmetic mean of the surface area of three glass plates wetted with the solution mixture, expressed as a percentage.

The wettability of the mortar adhesive mixture is taken as the time interval at which the surface of the glass plate is wetted with the mortar mixture by more than 50%.

Annex B (mandatory). Method for determining the strength of the adhesive bond (adhesion) and open time

Annex B
(mandatory)

B.1 Means of testing

Concrete slab according to GOST 31356.

Dry pressed ceramic unglazed tiles with water absorption less than 0.5% by weight, with a flat adhesive surface and face dimensions of [(50±1)(50±1)] mm.

Notched trowel with 66 mm tooth size and 12 mm tooth center distance.

Load weighing 2 kg with cross-sectional dimensions not exceeding 5050 mm.

Testing machine for determining the strength of adhesion (adhesion) of the adhesive mixture with the base, having sufficient power and sensitivity for testing. The machine must, by means of a suitable connection that does not create a bending force, provide a tensile load to the dies at a rate of load increase of (250 ± 50) N/s.

Square metal dies measuring [(5050)±1] mm and having a minimum thickness of 10 mm, having a suitable fixture for connection to the testing machine.

Drying cabinet, the temperature in which can be adjusted with an accuracy of ± 3 ° C.

B.2 Preparation for testing

All materials used can withstand at least 24 hours under normal conditions. As normal conditions (normal climate) take temperature (20 ± 2) ° C, relative humidity (60 ± 10)%, air circulation speed in the test area is less than 0.2 m / s.

The preparation of the mortar mixture is carried out in accordance with the requirements of GOST 31356.

B.3 Preparation of specimens

A mortar mixture is applied on a concrete slab with a trowel in two layers: the first layer is 1-2 mm thick, the second is 6-8 mm thick and smoothed with a notched trowel. The notched trowel is held at a 60° angle to the slab and perpendicular to the top edge of the slab.

After 5 minutes, five ceramic tiles are glued onto the mortar mixture at a distance of at least 50 mm from each other and each tile is pressed by 30 with a load of 2 kg.

When preparing samples for determining the open time, ceramic tiles are glued to the mortar mixture after 10 minutes for adhesive mixtures of classes F, after 30 minutes for mixtures of class E and after 20 minutes for adhesive mixtures of all other classes.

B.4 Sample storage and testing

B.4.1 Adhesive bond strength after air-dry exposure

After 27 days of storage under normal conditions, stamps are glued to the tiles using a suitable high-strength adhesive (e.g., epoxy) and, after 24 hours, the strength of the adhesive joint is determined by applying a load to the stamp at a constant rate of increase (250 ± 50) N / s.

When testing fast-hardening adhesive mixtures, the strength of the adhesive joint is additionally checked 6 hours after gluing the tiles when the samples are stored under normal conditions.

B.4.2 Adhesive strength after exposure to water

The test specimens are made in accordance with B.3.

The samples are kept for 7 days at a temperature of (20±2)°C. After 20 days, the samples are removed from the water, wiped dry with a towel, and stamps are glued to the tiles using a suitable high-strength adhesive (for example, epoxy). After 7 hours, the samples are again immersed in water at normal temperature.

The next day, the samples are removed from the water and the strength of the adhesive bond is determined by applying a load to the stamp at a constant rate of increase (250±50) N/s.

The results are given in newtons.

B.4.3 Bond strength after exposure to high temperatures

The test specimens are made in accordance with B.3.

The samples are kept for 14 days under normal conditions, then they are stored for 14 days in an oven at a temperature of (70 ± 3) ° C, after which the samples are removed from the oven and stamps are glued to the tiles using a suitable high-strength adhesive (for example, epoxy).

The samples are kept for another 24 hours under normal conditions, after which the strength of the adhesive joint is determined by applying a load to the stamp at a constant rate of increase (250±50) N/s.

The results are given in newtons.

B.4.4 Bond strength after freeze and thaw cycles

The test specimens are made in accordance with B.3.

Before gluing the tile, a layer of mortar mixture with a thickness of approximately 1 mm is additionally applied to its reverse side with a trowel.

Samples are kept for 7 days under normal conditions, then stored in water for 21 days, after which they are subjected to 25 cycles of freezing and thawing.

The freeze and thaw cycle is carried out as follows:

1) the samples are removed from the water and placed in a refrigerator, where the temperature is maintained at minus (15±3)°C for 2 h±20 min;

2) the samples are kept in the chamber at a temperature of minus (15±3)°С for 2 h±20 min;

3) samples are immersed in water with a temperature of plus (20±3)°C. The temperature of the water with the samples should not be lower than plus (15±3)°С.

At the end of the last cycle, the samples are removed from the water, wiped dry and stamps are glued to the tiles. The samples are kept for another 24 hours under normal conditions, after which the strength of the adhesive joint is determined by applying a load to the stamp at a constant rate of increase (250±50) N/s.

The results are given in newtons.

B.5 Determining the type of failure

When determining the strength of an adhesive joint, the following types of destruction can be:

- adhesive failure.

Failure occurs at the interface between the surfaces of the adhesive and the AF-S base (Figure B.1) or between the surfaces of the ceramic tile and the adhesive AF-T (Figure B.2). In both cases, the test results are equal to the rated strength of the adhesive joint.

NOTE Adhesive failure may occur between the surfaces of the ceramic tile and the BT steel die (Figure B.3). The normalized strength of the adhesive joint is higher than the strength obtained during the test. The tests should be repeated;

- cohesive failure.

Failure occurs inside the CF-A adhesive layer (Figure B.4), in the CF-S base (Figure B.5), inside the CF-T ceramic tile (Figure B.6).

Note - In cohesive failure, the strength of the adhesive solution is greater than the strength obtained during the test.