V.A. Clevtsov, Dr. Tehn. Sciences (head of the topic); M.G.Korvevitskaya, Cand. tehn sciences; Yu.K. Matsev; V.N.Artamonova; N.S.Vostrov; A.A. Grebenik; G.V.Sizov, Cand. tehn sciences; D.A. Korshunov, Cand. tehn sciences; M.V. Sididenko, Cand. tehn sciences; Yu.I. Kurash, Cand. tehn sciences; A.M. Leschinsky, Cand. tehn sciences; V.R.Abramovsky; V.A.Dorf, Cand. tehn sciences; E.G.Sorkin, Cand. tehn sciences; V.L. Chernyakhovsky, Cand. tehn sciences; I.O. Krolo, Cand. tehn sciences; S.Y.Vomatechenko; I.E. Ganin; O.Yu.Sammal, Cand. tehn sciences; A.A.Rulkov, Cand. tehn sciences; P.L.Talberg; A.I. Markov, Cand. tehn sciences; R.O. Krasnovsky, Cand. tehn sciences; L.S.pavlov, Cand. tehn sciences; M.Yu. Leschinsky, Cand. tehn sciences; G.A. Merkivsky; I.E.shkolnik, Cand. tehn sciences; I.Y. Lapenis, G.I. Winggarten, Cand. tehn sciences; N. B. Zhukovskaya; S.P. Abramova; I.N. Nagornok

This standard applies to heavy and lightweight concrete and establishes methods for determining compression strength in structures on elastic rebound, impact pulse, plastic deformation, separation, ribs, and leaving the rolling.

The size of the imprint on concrete (diameter, depth, etc.) or the ratio of the diameters of prints on concrete and the standard sample when the indenter is impaired or indenting an indenter into the surface of the concrete;

The value of the voltage required for the local destruction of concrete when the metal disk was glued to it, equal to the separation force divided into the area of \u200b\u200bprojection of the surface of the concrete separation to the disc plane;

1.3. Mechanical non-destructive testing methods are used to determine the strength of the concrete of all types of normalized strength controlled according to GOST 18105, as well as to determine the strength of concrete during examination and rejection of structures.

1.4. Tests are carried out at a positive temperature of concrete. Allowed when examining structures to determine the strength at negative temperatureBut not less minus 10 ° C provided that by the time of freezing the design was at least one week at a positive temperature and relative humidity of no more than 75%.

1.5. Assessment of the conformity of the values \u200b\u200bof the actual strength of concrete obtained using the methods given in this standard established requirements are produced according to GOST 18105.

2.1. Concrete strength is determined using instruments intended to determine the indirect characteristics that have passed the metrological certification according to GOST 8.326 * and meet the requirements shown in Table 2.

2.2. The tool for measuring the diameter or depth of prints (angular scale according to GOST 427, the caliper according to GOST 166 et al.) Used for the method of plastic deformations, should ensure measurements with an error of no more than ± 0.1 mm, and the tool for measuring the imprint depth (indicator hourly type according to GOST 577, etc.) - with an error of no more than ± 0.01 mm.

Other anchor devices are allowed, the sealing depth of which should be no less than the maximum size of the large-scale concrete aggregate of the test structure.

2.5. For the separation method, it is necessary to use steel discs with a diameter of at least 40 mm, a thickness of at least 6 mm and at least 0.1 diameters, with the roughness parameter of the glued surface of at least 20 microns according to GOST 2789. The glue for the disk glue should provide strength at which

3.1. To determine the strength of concrete in structures, there is a graduation dependence between the strength of the concrete and the indirect characteristic of the strength (in the form of a graph, table or formula).

For the rolling separation method, in the case of the use of anchor devices in accordance with Appendix 2, and for the rib, in the case of applying devices in accordance with Annex 3, it is allowed to use the calibration dependences given in Appendices 5 and 6, respectively.

Excerpts from GOST 22690 Determining the strength of mechanical methods of non-destructive testing

TESTING

4.1. Tests are carried out on a plot of design with an area of \u200b\u200b100 to 600 cm 2.

4.2. Concrete strength in a controlled construction site is determined by graduation dependenceestablished in accordance with the requirements of section. 3, provided that the measured values \u200b\u200bof the indirect indicator are between the smallest and the greatest values indirect indicator in samples tested in constructing calibration dependence.

4.3. The number and location of controlled sections when testing structures must comply with the requirements of GOST 18105-86 or specify in standards and (or) technical conditions on teams or in working drawings on monolithic structures and (or) in technological cards To control. When determining the strength of the examined structures, the number and location of the plots should be accepted under the survey program.

4.4. The number of tests on one site, the distance between the test sites on the site and from the structure of the structure, the thickness of the design on the test area must be at least the values \u200b\u200bgiven in Table. 3.

Table 3 mm

4.5. The surface roughness of the construction of the construction concrete during testing methods of rebound, shock pulse, plastic deformation should correspond to the roughness of the surface of cubes tested when setting calibration dependence. In the necessary cases, stripping the surface of the structure is allowed. When tested by plastic deformation under indulgence, if the zero count is removed after the application of the initial load, the requirements for roughness of the surface of the concrete structures are not presented.

4.6. Method of elastic rebound

4.6.1. When testing the method of elastic rebound, the distance from the venues of the test to the reinforcement should be at least 50 mm.

4.6.2. The test is carried out in the following sequence: the device is placed so that the force is applied perpendicular to the surface under test in accordance with the instruction manual; The position of the device when testing the design relative to the horizontal is recommended to be taken as when testing samples to establish calibration dependence; With a different position, it is necessary to amend the testimony in accordance with the instruction manual; fix the value of the indirect characteristic in accordance with the instruction manual; Calculate the average value of the indirect characteristic on the construction site.

4.7. Plastic deformation method.

4.7.1. When testing the method of plastic deformation, the distance from the venues of the tests to the reinforcement should be at least 50 mm.

4.7.2. The test is carried out in the following sequence: the device is placed so that the force is applied perpendicular to the surface under test in accordance with the instruction manual; With a spherical indenter, the test is allowed to be carried out to facilitate measurements of the diameters of prints through the sheets of copier and white paper (in this case, the samples for establishing calibration dependents are tested using the same paper); fix the values \u200b\u200bof the indirect characteristic in accordance with the instruction manual of the device; Calculate the average value of the indirect characteristic on the construction site. 4.8. Impact impulse method

4.8.1. When testing the impact pulse method, the distance of the test points to the reinforcement should be at least 50 mm.

4.8.2. Tests are carried out in the following sequence: the device is placed so that the force is applied perpendicular to the surface under test in accordance with the instruction manual; The position of the device when testing the design relative to the horizontal is recommended to be taken as when testing samples to establish calibration dependence; With a different position, it is necessary to amend the testimony in accordance with the instruction manual; fix the value of the indirect characteristic in accordance with the instruction manual; Calculate the average value of the indirect characteristic on the construction site.

4.9. Outflow method

4.9.1. When tested by the method of separation, the sections should be located in the zone of the lowest stresses caused by the operational load or force of the compression of pre-stressed reinforcement.

4.9.2. The test is carried out in the following sequence: in the place of the disk glue, the surface layer of the concrete is removed with a depth of 0.5 - 1 mm and the surface is purified from dust; The disc is glued to concrete so that the layer of glue on the surface of the concrete did not go beyond the disk; The device is connected to the disk; The load smoothly increases at a speed (1 p 0.3) kN / s; fix the reading of the device's power meter; Measure the area of \u200b\u200bprojection of the surface of the separation on the disc plane with the error P0.5 cm 2; Determine the value of the conditional voltage in the concrete during the separation. The test results do not take into account if, when the concrete is separated, the reinforcement or the area of \u200b\u200bprojection of the separation surface was less than 80% of the disk area.

4.10. The method of separation with the parking lot 4.10.1. When testing by the rolling method, the sections should be located in the low voltage zone caused by the operational load or enhanced the compression of pre-hard fittings.

4.10.2. Tests are carried out in the following sequence: if the anchor device has not been installed before concreting, then in the concrete, the shpor is drilled or penetrated, the size of which is chosen in accordance with the instruction manual, depending on the type of anchor device; An anchor device is fixed to the depth, provided for by the instruction manual, depending on the type of anchor device; The device is connected to an anchor device; The load is increased at a speed of 1.5 - 3.0 kN / s; The reading of the filament of the device and the depth of the separation with an accuracy of at least 1 mm is fixed. If the greatest I. the smallest dimension The eliminated part of the concrete from the anchor device to the borders of the destruction on the surface of the design differ more than doubled, and also if the depth of the breakdown differs from the depth of sealing the anchor devices by more than 5%, then the test results are allowed only to take into account the indicative assessment of concrete strength.

4.11. Rib Ribbon Method

4.11.1. When testing the rib ribbling method on the test section, there should be no cracks, concrete glasses, spills or shells height (depth) more than 5 mm. Plots should be located in the zone of the smallest stresses caused by the operational load or force of the compression of pre-hard fittings.

4.11.2. The test is carried out in the following sequence: the device is fixed on the design, apply the load at no more than (1 p 0.3) kN / s; fix the reading of the device's power meter; Measure the actual depth of the rock; Determine the average value of the brightness. The test results do not take into account if the reinforcement was naked when the concrete was rooted and the actual bright depth was different from the specified (see Appendix 3) by more than 2 mm.

Concrete strength on compression is the main indicator that characterizes concrete.

There are two expressions of this indicator:

Concrete strength on compression is the main indicator that characterizes concrete. It is on him that the non-destructive testing of concrete strength in monolithic structures. There are two expressions of this indicator:

• Concrete class, b - This is the so-called cube strength (i.e., a compressible sample in the form of a cube), showing the maintained pressure in MPa. The share of the probability of destruction during the test of concrete on strength does not exceed 5 units of 100 test samples. Denoted by the Latin letter B and the number showing the strength in MPa. According to SNiP 2.03.01-84 "Concrete and reinforced concrete structures".
• Concrete brand, m - This is the tensile strength of concrete for compression, kgf / cm². It is indicated by the Latin letter M and numbers from 50 to 1000. The maximum deviation that allows monitoring and assessment of concrete strength according to GOST 26633-91 "Concretes heavy and fine-grained - 13.5%.

Brand of concrete and class are determined after 28 days from the day of the fill, under normal conditions, or the calculation is carried out taking into account the coefficient (after 7-14 days, the material acquires 60-80% of the varying strength, after 28 days of about 100%, after 90 days -130% .). The ultrasonic method of non-destructive control of concrete is carried out, as a rule, in the intermediate and design age of reinforced concrete design.

The strength of concrete is influenced by a number of factors: cement activity, cement content, water ratio to cement by weight, quality of aggregates, mixing quality and degree of sealing, age and conditions of hardening concrete, re-vibration. The temperature and humidity of the medium has a great influence on the velocity of concrete. The conditionally normal is considered the medium with a temperature of 15-20 ° C and air humidity of 90-100%. With an increase in cement content in concrete, its strength grows to a certain limit. It is then grows slightly, the other properties of concrete deteriorate: the shrinkage increases, creep. Therefore, no more than 600 kg of cement is not recommended for 1 m³ of concrete.

Compliance of the brand of concrete (m) class (B) and compression strength

Rocking methodit takes a special place in a number of non-destructive methods for determining concrete strength. Believed non-destructive methodThe method of separation with the cream in its essence is the destructive method, since concrete strength is estimated in an effort necessary to destroy a small amount of concrete, which allows you to most accurately assess its actual strength. Therefore, this method is applied not only to determine the strength of the concrete of an unknown composition, but also can serve to build calibration dependencies for other non-destructive testing methods. This method is applied to heavy concrete and structural concrete concrete on light aggregates in monolithic and precast concrete and reinforced concrete products, structures and structures and sets the method of testing concrete and determining its compression strength by local destruction of concrete when the special anchor device is separated from it. Such ultrasonic Method of Concrete Strength Allows you to determine the strength to compression for concrete in the range of strengths from 5.0 to 100.0 MPa. When developing the standard, materials are GOST 22690-88.

One of the most common and effective ways Non-destructive testing of the determination of concrete strength is the measurement of the sclerometer, or as it is also called the Schmidt hammer.

Concrete strength definition methods: Equipment used

With the help of the devices presented below, it is possible to test concrete to a non-destructive method. It allows you to more accurately predict physical characteristics Ready reinforced concrete structuresSo it means to minimize the losses of the construction organization and protect the customer of work from all sorts of trouble.

Among other things, such a quality control of concrete allows components of concrete, the temperature of which dropped below 0ºС. Traditional methods of controlling the quality of concrete in the laboratory conditions, such convenience can not boast: previously had to take a sample and check it at room temperature In laboratory conditions. Interesting modern solution Also, the contractors may not resort to the services of relevant organizations at each stage construction work. In turn, experts can independently come to the object and conduct an examination of the quality of concrete in accordance with the provisions of GOST. The equipment is compact enough and mobile, and the preparation of results takes a minimum of time.

Used equipment

Schmidt Hammer Original Schmidt Type N

Test products made of concrete using the Schmidt Schmidt's Schmidt Schmidt - the most common method of measurement method that does not destroy concrete in accordance with GOST 22690-2015

For each specific type of product tests from concrete, Proceq offers the appropriate hammer model.

Schmidt hammer models are available for testing concrete products Type Original Schmidt with different impact energies for testing materials of a variety of types and sizes.

Our hammers N, NR, L and LR types are specifically designed to assess the quality and strength to compress concrete products with a range from 10 to 70 N / mm2 (from 1,450 to 10,52 pounds / square meters).

Models with built-in paper scrappers (LR and NR) are capable of automatically registering the rebound values \u200b\u200bon paper tape.

Schmidt Hammer Brochure Brochure Certificate

Pos-50mg4 "Skole" is intended for non-destructive testing of concrete strength by the ribs of ribs, separating with the rocking and separation of steel discs according to GOST 22690-2015.

Measuring the strength of concrete with the help of such equipment is allowed both on the erected projects and at the finished buildings. The device is indispensable in the construction sector, in the work of public utilities and restoration bureaus, periodically inspecting the integrity of buildings. The model received a non-volatile memory in which two hundred of the latest measurement results are preserved. They are marked with a brand of concrete and an accurate date of analysis, allowing experts to easily track the dynamics of changing key indicators.

State Standards of the SSR Union

Concrete heavy

Methods for determining the strength without disruption of mechanical devices

Official edition

State Committee of the USSR on the standards of Moscow

UDC 691.32: 620.17: 006.354 Group G19

State Standard of the SSR Union

Concrete heavy

General requirements for the methods of determining the strengthless destruction of mechanical devices

Concrete. General Requirements for Methods of NondestRUCTIVE STRENGTH DETERMINATION BY THE MECHANICAL DEVICES

Resolution State Committee Council of Ministers of the USSR on construction activities of August 22, 1977 No. 128 The deadline for administration is established

from 01.07. 1978

Failure to comply with the standard is prosecuted by law.

1. This standard applies to heavy concrete and establishes general requirements To the methods for determining its compression strength in products and structures of mechanical action to rebound, plastic deformation, the ribbling of the rib design and the separation.

Determination of concrete strength by the method of separation with the rocky - according to GOST 21243-75.

2. Concrete strength is determined by pre-established experimentally gradual dependencies between the strength of concrete samples, tested according to GOST 10180-78, and the indirect characteristics of the strength of concrete (rebound value, the size of the imprint, the string of the rib of construction, conditional voltage under the separation) of those installed non-destructive tests of those same samples.

3. To construct calibration dependencies, samples - Cubes, which meet the requirements of GOST 10180-78 and having dimensions, see:

15x15x15 - for rebound and plastic deformation methods;

20x20x20 - the ribs of the rib of construction and separation.

Edition Official Reprint is prohibited

Reprint. November 1981

© Standards Publishing House, 1982

Op. 10 GOST 22690.0-77

The shape of the concrete strength of concrete in structures

1. Test object ________

2. Test date _

3. The name of the design (for prefabricated structures - Mark, a series of work drawings) _ "_

4. View of concrete and its design strength _

5. Test method, device, pulp parameters (impact energy, indenter size or disc area, stall material, etc.).

6. Test results (see table)

P. 2 GOST 22690.0-77

The gradding dependence for monitoring the strength of the concrete of one brand is set by the test results of at least 20 episodes, each of which consists of three twin samples. Samples must have the same composition, as well as the duration and conditions of hardening with concrete used for the manufacture of controlled structures. Made samples for two weeks (no less) in different shifts. To obtain calibration dependence in a wider range of strength changes, up to 40% of samples should be made with a deviation of cement-growing ratio to ± 0.4. The rejection of the abnormal test results of the samples is carried out at mandatory annex 1.

4. When monitoring the strength of concrete in the erected structures from various sections, at least 20 cubic samples are cut out, while the test result of one sample is equal to the test result of the sample series.

It is allowed to establish a calibration dependence of cubes with a side of at least 7.07 cm or cores with a diameter of at least 7.14 cm. In this case, the following test order should be. In the construction site, non-destructive tests are carried out, then cut the sample and test it for compression. The boundaries of the test zones of the non-destructive method and cutting of the sample should be from each other at a distance of no more than 100 mm.

5. Graduation dependence should be installed at least twice a year, as well as when the materials applied to the preparation of concrete, and the manufacturing technology of structures.

The method of calculating the equation of the calibration dependence is given in the recommended Appendix 2, and an example of its construction is in the reference application 3.

6. Evaluation of the error of graduation dependence is carried out according to GOST 17624-78.

7. Experts of specialized research organizations may conduct an indicative assessment of concrete strength, using a graded dependence established for concrete, differing from the test (according to the composition, age and experimental conditions), with clarification of it according to the results of a test of at least three cut samples or three tests. Method of separation with the parking lot according to GOST 21243-75.

8. Devices seized to determine the strength of concrete should undergo a departmental verification at least once every two years, as well as after each repair or replacement of parts. The results of the verification must be decorated with the act.

9. Plots for the test of concrete should be chosen on the surfaces of the design in contact with the manufacture with a metal, stringent wooden or other smooth formwork. EU-

GOST 22690.0-77 p. 3.

whether the surface of the design has a finish, then it must be removed before testing.

10. Strength should be determined at a positive temperature of concrete.

11. Concrete strength on the construction site is determined by the average value of the indirect characteristic of concrete strength in this area, using the established calibration dependence, taking into account the rejection of the abnormal results produced by the mandatory annex 1.

The test results should be logged into a magazine, the form of which is provided in the recommended Annex 4.

12. Control and assessment of concrete strength on compression and its homogeneity in structures - according to GOST 18105.0-80-GOST 18105.2-80.

P. 4 GOST 22690.0-77

Appendix 1 Mandatory

Rules for rejection of abnormal test results

1. The rejection of the abnormal test results (A *) is carried out with the number of results at least 3 by formula (1):

a) for the result of the test on the press of one sample in the series;

b) for a single test result by non-destructive method in one sample;

c) for a single test of testing non-destructive method n-a Plot design.

2. The result of the test recognize the abnormal and not taken into account when calculating

if the value of T, determined by formula (1), exceeds the permissible value of the TC, shown in Table. one. _

where A is the average strength of concrete in a series of samples, the average test result by the non-destructive method of one sample or construction site;

5 is the average quadratic deviation determined by calculating the calibration dependence by formula (2).

Table 1

Meaning T I.

where D is the coefficient taken in Table. 2;

XI Shah and XI Min - maximum and minimum test results in a series of samples or in a separate sample;

N is the number of series (case A) or the number of individual samples (case b) used in constructing calibration dependence.

When evaluating the abnormality of individual test results in areas of structures, the value s is taken equal to the calculated for individual samples when constructing calibration dependence.

table 2

Coefficient value D.

GOST 22690.0-77 p. five

Method of calculating the equation of calibration dependence "indirect characteristic - strength"

Equation of the "indirect characteristic - strength" adoption:

when the range of concrete strength is up to 200 kgf / cm 2 - linear:

when the range of concrete strength is over 200 kgf / cm 2 exponential:

R - b 0 - / b, n. (2)

Factors about 0; Ai h is calculated by formulas.

# 0 - R- (I \\ '//, * (3)

"\u003d '-H? -Z-: (4)

2 (HI-77) (in ri-uir)

The average values \u200b\u200bof the strength of R and indirect characteristics I needed to determine these coefficients are calculated by formulas:

* \u003d Чг:< 7 >

In /? - \u003d * "" s -; (nine)

Ri and Hi values \u200b\u200bare respectively values \u200b\u200bof the strengths and indirect characteristics for individual series of three samples (or one sample), and N is the number of series (or individual samples) used to build calibration dependence.

It is allowed to use the level (1) level (or graphic construct) of calibration dependence in cases where the error and efficiency coefficient of the dependence, determined according to GOST 17624-78 are in the allowed limits.

The estimate of the error of graduation dependence is carried out according to GOST

P. 6 GOST 22690.0-77

Appendix $ reference

Examples of constructing calibration dependence and rejection of the abnormal test results

Construction of calibration dependence

Concrete strength M250 design brand is controlled by the rebound method by the KM device. To build a relationship between the magnitude of the rebound (s) and the strength to compress control samples on the press (/?) 29 series of samples were tested (A g * \u003d 29). The average results for each series are given in Table. !.

Table 1

Since the range of measuring the strength of concrete 330-169 "\u003d" 170 kgf / cm * is less than 200 kgf / cm *, then in accordance with the method described in the recommended Annex 2, the equation of the desired dependence is taken linear: * \u003d oo + a g I. equation coefficients Calculate, substituting the data of Table V_Foriolez (3) and (4) of the recommended application 2.

I am * 252.9 kgf / cm 3; h "18.24; "36.76; CO - 417.79.

The calibration dependence "the magnitude of the rebound - strength" is expressed by equation # "36.76 I-413.

The dependency graph is given in the drawing.

GOST 22690.0-77 p. one

Dependence "indirect characteristic (rebound value) - strength"

R, kgf / cm 1

Calculation of medium quadratic deviations for strength in a series of 3 samples and by the magnitude of the rebound in 5 measurements on one sample.

When constructing calibration dependence (see example i), 29 series of 3 samples were tested. In each sample, the magnitude of the rebound was determined at 5 points. The sample from the test results table is given in Table. 2.

table 2

Page, 8 GOST 22690.0-77

Continued

The average quadratic deviation of concrete strength in the sample series, defined by formula (2) and Table. 2, will be

S- --- - \u003d 18 KIX / CM L.

By the same formula, the average quadratic deviation of the height of the rebound on the device KM in samples is calculated

4,1+2,9+2,5+3,3+2,1+1,9+...

YTSH-- "" 5<е *’

In the second series (see example 2) the strength of the third sample differs significantly from the middle in the series. To verify the abnormality of this result by the formula (1) of the mandatory application 1 calculate the magnitude

GOST 22690.0-77 p. nine

what is less than the value defined by table T to -1.74 for three samples in the series. Consequently, the result of 252 kgf / cm 2 should not be excluded when determining concrete strength in the second series of samples.

In the first sample of the first series (see example 2) the result of 16.0 cases. It differs significantly from the average sample value. To verify the abnormality of this result by the formula (1) of the mandatory application 1 calculate the magnitude

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