Test of concrete GOST 22690. Determining the strength of mechanical methods of non-destructive testing. Processing and design of results
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 is focused. 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
|
Brand concrete, m |
Concrete class, b |
Strength, MPa |
Strength, kg / cm 2 |
Rocking methodit takes a special place in a number of non-destructive methods for determining concrete strength. Considered the non-destructive method, the separation method with the rocking in its essence is a destructive method, since the strength of the concrete is estimated in an effort necessary to destroy a small volume 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 efficient methods of non-destructive testing of determining 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. This allows you to more accurately predict the physical characteristics of finished reinforced concrete structures, which means it is 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 Control Quality of Concrete In Laboratory Conditions, such convenience can not boast: previously had to take a sample and check it at room temperature in laboratory conditions. Interestingly, the modern decision also because contractors may not resort to the services of relevant organizations at each stage of 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.
Models of Schmidt hammers for test products of type Original Schmidt with different impact energies for testing materials of various types and sizes are available.
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.
Interstate Council for Standardization, Metrology and Certification
INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION
Interstate
STANDARD
Concretes
Determining the strength of non-destructive testing mechanical methods
(EN 12504-2: 2001, NEQ)
EN 12504-3: 2005, NEQ)
Official edition
Ritinform Stand 2016.
Preface
Objectives, basic principles and the main procedure for conducting work on interstate mill, dartization is established by GOST 1.0-92 "Interstate standardization system. Basic provisions "and GOST 1.2-2009" Interstate standardization system. Standards interstate. Rules and recommendations on interstate standardization. Rules for the development, adoption, applications, updates and cancellations »
Information about standard
1 Developed by the structural unit of NIC Construction of the Construction of Research. Design and design and technological institution of concrete and reinforced concrete. A.A. Nail (niizb)
2 Submitted by the Technical Committee on Standardization TC 465 "Construction"
3 Adopted by the Interstate Council for Standardization, Metrology and Certification (Protocol of June 18, 2015 No. 47)
4 by the order of the Federal Agency for Technical Regulation and Metrology of September 25, 2015 No. 1378-ST Interstate Standard GOST 22690-2015 was enacted as a national standard of the Russian Federation from April 1, 2016.
5 8 This standard includes basic regulations in terms of requirements for mechanical methods of non-destructive testing of concrete strength of the following European regional standards:
EN 12504-2: 2001 Testing Concrete In Structures - Part 2: Non-Destructive Testing - Determination of Rebound Number (Concrete Testing in Designs. Part 2. Non-destructive testing. Definition of the criterion of the rebound);
EN 12504-3: 2005 Testing Concrete in Structures - Determination of Pull-Out Force (Concrete Testing in Designs. Part 3. Definition of bulk effort).
The degree of conformity is non-equivalent (NEQ)
6 83Aname GOST 22690-88
Information about the changes to this standard is published in the annual information of the National Standards Index, and the text of the change and amendments to the monthly information indicator "National Standards". In case of revision (replacement) or the cancellation of this standard, the corresponding notification will be published by the monthly information indicator * 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
© Standinform. 2016.
In the Russian Federation, this standard can be fully or partially reproduced. replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology
Appendix A (compulsory) Standard test diagram by the method of separation with the crease. . . 10
Interstate standard
Determining the strength of mechanical methods of neraerous control
Determination Of Strength by Mechanical Methods of NondestRUCTIVE Testing
Date of introduction - 2016-04-01
1 area of \u200b\u200buse
This standard applies to structural heavy, fine-grained, light and straining concrete monolithic, prefabricated and combined-monolithic concrete and reinforced concrete products. Constructions and structures (hereinafter - constructions) and establishes mechanical methods for determining concrete compression strength in structures on elastic rebound, shock pulse, plastic deformation, separation, ribbling the ribs, etc.
8 This standard uses regulatory references to the following interstate standards:
GOST 166-89 (ISO 3599-76) caliper. Technical conditions
GOST 577-68 Indicators FIRSTPACEINE EXECTION 0.01 mm. Technical conditions
GOST 2789-73 surface roughness. Parameters and characteristics
GOST 10180-2012 Concretes. Methods for determining the strength of control samples
GOST 18105-2010 Concretes. Rules for monitoring and assessing strength
GOST 28243-96 Pyrometers. General technical requirements
GOST 28570-90 concrete. Methods for determining the strength of samples selected from the designs
GOST 31914-2012 High-strength heavy and fine-grained concrete for monolithic structures. Rules of control and quality assessment
Note - When using this standard it is advisable to verify the action of reference standards in the public information system - not the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or by the annual information indicator "National Standards", which is published as of January 1 of the current year, and on the issues of the monthly information pointer "National Standards" for the current year. If the reference standard is replaced (changed), then when using this standard should be guided by replacing (modified) standard. If the reference standard is canceled without replacement, the position in which the reference to it is applied in a part that does not affect this link.
3 Terms and Definitions
8 These Standard applied terms according to GOST 18105. And also the following terms with the corresponding definitions:
Official edition
destroying methods for determining concrete strength: determination of concrete strength according to control samples made from concrete mix according to GOST 10180 or selected from designs according to GOST 28570.
[GOST 18105-2010. Article 3.1.18]
3.2 Non-destructive mechanical methods for determining the strength of concrete: Determination of concrete strength directly in the design with a local mechanical effect on concrete (blow, separation, chip, indulgence, separation with the rocking, elastic rebound).
3.3 Indirect nera-erecting methods for determining concrete strength: determination of concrete strength according to pre-installed calibration dependencies.
3.4 Straight (standard) non-destructive methods for determining concrete strength: Methods providing for standard test diagrams (separation with the rolling and rocking of the edge) and allowing the use of known calibration dependences without binding and adjustment
3.5 Conditional dependence: Graphic or analytical dependence between the indirect characteristic of the strength and strength of concrete on a compression determined by one of the destructive or direct non-destructive methods.
3.6 indirect characteristics of strength (indirect indicator): the magnitude of the applied force during the local destruction of the concrete, the magnitude of the rebound, the power of the blow, the size of the imprint or other indication of the device when measuring the strength of the concrete by non-destructive mechanical methods.
4 General
4.1 Non-destructive mechanical methods are used to determine the strength of concrete for compression in the intermediate and design age installed project documentation and in the age of the project, during the examination of the structures.
4.2 Non-destructive mechanical methods for determining concrete strength, established by this standard, are subdivided by the type of mechanical impact or determined indirect characteristics on the method:
Elastic rebound;
Plastic deformation;
\u003e Impact pulse:
Ottay with a smoking:
Ribs ribs.
4.3 Non-irreshable mechanical methods for determining concrete strength are based on concrete strength with indirect strength characteristics:
The method of elastic rebound on the connection of concrete strength with the value of the rebound of the bridge from the surface of the concrete (or the drummer pressed to it);
Plastic deformation method for concrete strength with imprint size on concrete design (diameter, depth, etc.) or the ratio of the diameter of the imprint on concrete and a standard metallic sample when the indenter is impaired or indenting an indenter into the surface of the concrete;
The impact pulse method for the connection of concrete strength with the energy of the impact and its changes at the time of the collision of the coach with the surface of the concrete;
The separation method for the supply of the voltage required for the local destruction of concrete when the metal disk is glued to it, equal to the separation of the separation, divided into the area of \u200b\u200bthe projection of the concrete separation on the disc plane;
The separation method with the creation of concrete strength with the value of the efforts of the local destruction of concrete when an anchor device is energized;
The rib of ribs on the connection of concrete strength with the value of the effort required to rock the concrete section on the rib design.
4.4 In general, non-destructive mechanical methods for determining the strength of concrete are indirect nerawriting methods for determining strength. Concrete strength in structures are determined by experimentally installed calibration dependencies.
4.5 The separation method with the rolling during testing in accordance with the standard scheme for Appendix A and the rib ribbon method when conducting tests in accordance with the standard scheme for Appendix B are direct non-destructive methods for determining concrete strength. For direct non-destructive methods allowed to use calibration dependences set in applications B and G.
Note - Standard Test Schemes are applicable and a limited range of concrete strength (see Appendices A and B) for cases that are not related to standard test diagrams, gender dependencies should be installed in general rules.
4.6 The test method should be selected taking into account the data shown in Table 1. and additional restrictions established by the manufacturers of specific measurement tools. The use of methods outside of the concrete strength recommended in Table 1 is allowed in a scientific and technical justification based on research results using measurement tools that have passed the metrological certification for the extended range of concrete strength.
Table 1
4.7 Determination of the strength of heavy concretees of design classes B60 and higher or with the average strength of concrete on the compression R M i 70 MPa in monolithic structures should be carried out with regard to the provisions of GOST 31914.
4.8 Concrete strength is determined in areas of structures that do not have visible damage (detachment of the protective layer, cracks, cavities, etc.).
4.9 The age of concrete controlled structures and its sites should not differ from the age of concrete of structures (sections, samples) tested to establish calibration dependence, more than 25%. Exceptions are controlling the strength and construction of calibration for concrete, which exceeds two months. In this case, the difference in the age of individual structures (sections, samples) is not regulated.
4.10 Tests are carried out at a positive temperature of concrete. It is allowed to carry out tests under the negative temperature of concrete, but not lower than minus 10 "C, when establishing or binding the calibration dependence as a budgetary requirements 6.2.4. The temperature of the concrete during testing should correspond to the temperature provided for in the operating conditions of the instruments.
The calibration dependences mounted at the temperature of the concrete below * C are not allowed to be used at positive temperatures.
4.11, if necessary, testing concrete constructs after thermal treatment at a surface temperature T to 40 * C (for controlling the selling, gear and platform of concrete), the calibration dependence is set after determining the strength of concrete in the construction of an indirect non-destructive method at temperatures (I (T ± 10) * C, and concrete testing by direct non-destructive method or testing of samples - after cooling at normal temperatures.
5 Measurement Means, Equipment and Tool
5.1 Measurement Means and Mechanical Test Instruments, designed to determine concrete strength, must be certified and are attributed in the prescribed manner and must comply with the requirements of Appendix D.
5.2 Indications of devices graded in units of concrete strength should be considered as an indirect indicator of concrete strength. These devices should be used only after
establishing the graduation dependence "The testing of the device - the strength of concrete" or the binding of the dependence installed in the device in accordance with 6.1.9.
5.3 The tool for measuring the fingerprint diameter (s) 166), used for the method of plastic deformations, should ensure measurement with an error of no more than 0.1 mm. Instrument for measuring the depth of the print (hourly type indicator according to GOST 577, etc.) - with an error of no more than 0.01 mm.
5.4 Standard test diagrams of testing by the method of separation with the crease and chip edges provide for the use of anchor devices and captures in accordance with applications A and B.
5.5 For methodotypes, anchorustela should be applied to the methods. The depth of the sealing of which should be no less than the size of the large-scale concrete aggregate of the test design.
5.6 For the separation method, use steel discs with a diameter of at least 40 mm. The thickness of * no less than 6 mm and at least 0.1 diameter, with the roughness parameters of the glued surface at least Ra \u003d 20 microns according to GOST 2789. The glue for the disk glue should provide a combination strength with concrete at which the destruction occurs through concrete.
6 Test preparation
6.1 Procedure for preparing for testing
6.1.1 Preparation for testing includes verification of used devices in accordance with the instructions for their operation and the establishment of calibration dependences between the strength of concrete and the indirect characteristic of the strength.
6.1.2 Graduation dependence is established on the basis of the following data:
The results of parallel tests of the same stations of structures by one of the indirect methods and a direct non-destructive method for determining concrete strength;
The results of the tests of construction sites by one of the indirect nera-erecting methods for determining the strength of concrete and testing samples - cores selected from the same construction sites and tested in accordance with GOST 28570:
Test results of standard concrete samples by one of the indirect non-destructive methods for determining concrete strength and mechanical tests according to GOST 10180.
6.1.3 For indirect non-destructive methods for determining the strength of concrete, the calibration dependence is set for each type of normalized strength specified in 4.1 for the concrete of one nominal composition.
It is allowed to build one graduation dependence for the concretes of one type with one type of large aggregate, with a single production technology, differing from the nominal composition and the value of the normalized strength subject to the requirements of 6.1.7
6.1.4 The permissible difference between the age of the concrete of individual structures (sections, samples) when setting the calibration dependence on the age of concrete of the controlled design, accepted by 4.9.
6.1.5 For direct non-destructive methods of 4.5, it is allowed to use the dependences given in applications B and G for all types of normalized concrete strength.
6.1.6 The calibration dependence should have a rms (residual) deviation of S T n m. Not exceeding 15% of the average of the strength of the concrete of sections or samples used in constructing, and the coefficient (index) of the correlation is not less than 0.7.
It is recommended to use a linear dependence of the form R * A * bk (where R is the strength of concrete. K-indirect indicator). The method of establishing, evaluating parameters and determining the conditions for the application of a linear graduation dependence is given in Appendix E.
6.1.7 When constructing a calibration dependence of the deviation of unit values \u200b\u200bof the strength of concrete R ^ on the mean value of the strength of the concrete of sections or samples I f. Used to build calibration additives, must be within:
\u003e from 0.5 to 1.5 mean values \u200b\u200bof concrete strength I f n f £ 20 MPa;
From 0.6 to 1.4 mean values \u200b\u200bof concrete strength R, F with 20 MPa< Я ф £50 МПа;
From 0.7 to 1.3 average concrete strength R F at 50 MPa<Я Ф £80 МПа;
From 0.8 to 1.2 of the average value of concrete strength I am F. F\u003e 80 MPa.
6.1.8 The adjustment of the established dependence for concrete in the intermediate and project age should be carried out at least once a month, taking into account the addition of the results obtained. The number of samples or sections of additional tests during the adjustment must be at least three. The adjustment technique is given in Appendix E.
6.1.9 It is allowed to apply indirect non-destructive methods for determining concrete strength, using graded dependencies mounted for concrete, differing from the tested in composition, age, experimental conditions, humidity, with reference in accordance with the method of fibring.
6.1.10 without binding to specific conditions by Appendix W Conducting dependencies established for concrete, different from the subject, it is allowed to be used only to obtain approximate values \u200b\u200bof strength. It is not allowed to use indicative strength values \u200b\u200bwithout reference to specific conditions for assessing the concrete class by strength.
6.2 Construction of graduation dependence on the results of concrete strength tests
in structures
6.2.1 When constructing a calibration dependence on the results of the tests of concrete strength in structures, the dependence is set according to the single values \u200b\u200bof the indirect indicator and the strength of the concrete of the same sections of the structures.
For the unit value of the indirect indicator, the average value of the indirect indicator in the area is taken. For the unit value of concrete strength, the strength of the concrete section is taken, determined by a direct non-destructive method or test of selected samples.
6.2.2 The minimum number of single values \u200b\u200bfor building a calibration dependence on the results of the tests of concrete strength in structures - 12.
6.2.3 When constructing a calibration dependence on the results of the tests of concrete strength in the structures of non-test structures or their zones, the measurements of the indirect non-destructive method are pre-carried out according to the requirements of section 7.
Then selected areas in the amount provided for by 6.2.2, on which the maximum is obtained. Minimum and intermediate values \u200b\u200bof an indirect indicator.
After testing by an indirect non-destructive method, the plots are experiencing directly inevitable method or select samples for the test according to GOST 26570.
6.2.4 To determine the strength at a negative temperature of concrete, the sections selected for constructing or binding calibration dependences are first tested by an indirect neraer-catching method, and then select the samples for the subsequent test at a positive temperature or heated by external heat sources (infrared emitters, thermal guns and Dr.) At a depth of 50 mm to a temperature not lower than 0 * C and test the direct non-destructive method. Monitoring the temperature of he warmed concrete is carried out at the depth of the installation of anchor device in the prepared hole or on the surface of the unit, a contactless manner with a pyrometer according to GOST 28243.
The rejection of test results used to construct calibration dependences at a negative temperature is allowed only if deviations are associated with a violation of the test procedure. In this case, the rejected result should be replaced by the results of the re-test in the same design zone.
6.3 Construction of graduation dependence on control samples
6.3.1 When constructing a calibration dependence on control samples, the dependence is established by isolated values \u200b\u200bof the indirect indicator and strength of the concrete of standard sample cubes.
For the isolated value of the indirect indicator, the average value of indirect indicators for a series of samples or for a single sample is taken (if the calibration addiction is installed in separate samples). For the unit value of concrete strength, concrete strength in the GOST 10180 series or one sample (graduation dependence on separate samples) takes. Mechanical tests of samples according to GOST 10180 are carried out immediately after testing with an indirect neraelective method.
6.3.2 When building a calibration dependence on the results of test samples, at least 15 episodes of sample cubes according to GOST 10180 or at least 30 separate cubic samples are used. Samples are manufactured in accordance with the requirements of GOST 10180 in different shifts, for at least 3 days from the concrete of one nominal composition, on the same technology, with the same hardening mode as the design to be controlled.
The unit values \u200b\u200bof the strength of the concrete of sample cubes used to construct calibration addiction should correspond to the expectations on the production of deviations, while be within the ranges set by 6.1.7.
6.3.3 Graduation dependence For methods of elastic rebound, shock pulse, plastic deformation, separation and rolling edges, based on the test results of the manufactured sample cubes, first the non-destructive method, and then the destructive method according to GOST 10180.
When establishing a calibration dependence for the separation method with the cream, the main and control samples of 6.3.4 are manufactured. On the main samples determine the indirect characteristic. Control samples are tested according to GOST 10180. Basic and control samples must be made of one concrete and to harden in the same conditions.
6.3.4 Sample sizes should be selected in accordance with the largest size of the aggregate in the concrete mixture according to GOST 10180. But not less:
100 * 100 * 100 mm for rebound methods, shock pulse, aftic deformation. as well as for the method of separation with the parking (control samples);
200 * 200 * 200 mm For the rib of the rib design:
300 * 300 * 300 mm. But the sampler of the rib is at least six depths of the installation of an anchor device for the rolling separation method (main samples).
6.3.5 To determine the indirect characteristics of strength, tests are carried out according to the requirements of section 7 on the side (in the direction of concreting) the edges of the sample cubes.
The total number of measurements on each sample for the method of elastic rebound, the impact pulse, plastic deformation during the strike should be at least the set number of tests on the site according to Table 2. And the distance between the shocks is not less than 30 mm (15 mm for the impact pulse method). For the method of plastic deformation under induction, the number of tests on each face should be at least two, and the distance between the test sites is at least two diameters of the prints.
When establishing a calibration dependence for the rib method, the ribs are carried out by one test on each side edge.
When establishing calibration dependencies, for the separation method with the rocky, one tests on each side face of the basic film is carried out.
6.3.6 When testing the method of elastic rebound, a shock pulse, plastic deformation when the samples should be clamped in a press with an effort of at least (30 ± 5) kN and no more than 10% of the expected value of the destructive load.
6.3.7 Samples tested by the separation method are installed on the press so. In order for the supporting plates of the press did not flood the surface on which the disconse. Test results according to GOST 10180 increase by 5%.
7 Testing
7.1 General requirements
7.1.1 The number and location of controlled areas in constructions must comply with the requirements of GOST 18105 and specify in design documentation on the design or set aside:
Control objectives (determination of the actual class of concrete, platform or vacation strength, detecting sections of reduced strength, etc.);
Type of design (columns, beams, stoves, etc.);
Placing the capture and concreting order:
Reinforcement designs.
The rules for appointing the number of sections of the monolithic and prefabricated structures during the monitoring of concrete strength are given in Appendix I. When determining the strength of the concrete of the examined structures, the number and location of the sites should be accepted under the survey program.
7.1.2 Tests are carried out on a construction site with an area of \u200b\u200b100 to 900 cm.
7.1.3 Total number of measurements on a khazhaya area, the distance between the measurements on the site and from the edge of the structure, the thickness of the structures on the measurement site must be at least the values \u200b\u200bshown in Table 2 depending on the test method.
Table 2 - Test Requirements Requirements
|
Name method |
The total number of measurements is not a plot |
The minimum distance between the measurement places on the site, mm |
Minimum distance from the edge of the design to the place of measurement, mm |
Minimum design thickness, mm |
|
Elastic rebound | ||||
|
Impact impulse | ||||
|
Plastic defoction | ||||
|
Packing ribs | ||||
|
2 disk diameters | ||||
|
Targeting with a smoking at the working depth of the embezzlement of anchor l: * 40mm< 40мм |
7.1.4 Deviation of individual measurement results at each site from the average arithmetic value of the measurement results for this section should not exceed 10%. The measurement results that do not satisfy the specified condition are not taken into account when calculating the average arithmetic value of an indirect indicator for this site. The total number of measurements on each site when calculating the average arithmetic must comply with the requirements of the table 2.
7.1.5 Concrete strength E controlled section of the design is determined by the average value of the indirect indicator on the calibration dependence established in accordance with the requirements of section 6. Provided that the calculated value of the indirect indicator is within the limits set (or tied) dependencies (between the smallest and largest values) strength).
7.1.6 The roughness of the surface of the concrete section of structures when tested by the methods of rebound, a shock pulse, plastic deformation should correspond to the roughness of the surface of the construction sites (or cubes) tested during the establishment of calibration dependence. In the necessary cases, it is allowed to clean the surface of the structure.
When using the plastic deformation method at indulgence, if the zero count is removed after the application of the initial load, the requirements for the roughness of the surface of the concrete design are not presented.
7.2 Method of elastic rebound
7.2.1 Tests are carried out in the following sequence:
The position of the device when testing the design relative to the horizontal is recommended to be taken as the same. As with the establishment of calibration dependence. With a different position of the device, it is necessary to amend the indicators in accordance with the instruction manual:
7.3 Method of plastic deformations
7.3.1 Tests are carried out in the following sequence:
The device is placed so that the force is applied perpendicular to the surface test in accordance with the instruction manual;
When applying a spherical indvoderator to facilitate measurements of the diameters of prints, the test is allowed to fit the white paper copier sheets (VETSLUCHE tests for establishing calibration dependencies, carry out the use of 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.
7.4 Impact Impulse Method
7.4.1 Tests are carried out in the following sequence:
The device is placed so. So that the force is applied perpendicularly subject to top * 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 as well as when tested when setting calibration dependence. With a different position of the device, 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.
7.5 Outflow method
7.5.1 When tested by the method of separation, the plots should be located in the zone of the lowest stresses caused by the operational load or force the compression of pre-stressed reinforcement.
7.5.2 Testing is carried out in the following sequence:
In the place of the disk row, the surface spo is 0.5-1 mm deep and clean the surface from dust;
The disc is glued to concrete, pressing the disk and removing the excess glue outside the disk;
LIBOROVEDINEYSDIS;
Loads are plugged with soreness (1 ± 0.3) kN / s;
Fix the reading of the device's power meter;
Measure the area of \u200b\u200bprojection surface of the separation on the disc plane with an error of IO.SCM 2;
The value of the conditional voltage of the WBetone is determined when the abandonation of the maximum detachment effort to the surface of the surface of the separation is determined.
7.5.3 Test results do not take into account if the concrete revealed the reinforcement or the area of \u200b\u200bprojection of the separation surface was less than 80% of the area of \u200b\u200bthe disk.
7.6 Method of separation with the parking
7.6.1 When tested by the method of separation with the rolling, the sections should be located in the zone of the lowest stresses caused by the operational load or force of the compression of the presenter-intense reinforcement.
7.6.2 Tests are carried out in the following sequence:
If the anchor device was not installed before concreting, then the hole is performed in the concrete, the size of which is chosen in accordance with the instruction manual, depending on the type of anchor device;
The hole is fixed with an anchor device to a depth provided for by the instruction manual, depending on the type of anchor device;
The device is connected by a sanction device;
The load increases at a speed of 1.5-3.0 kN / s:
The reading of the Silicizer of the device P 0 and the magnitude of the slippage of the anchor of the LP (the difference between the actual depth of the outlet and the depth of the anchor seal) is not accuracy of Mecaire0.1 mm.
7.6.3 The measured value of the pulp P 4 is multiplied by the correction coefficient y. Defined by formula
where l is the working depth of sealing anchor device, mm;
DP - the magnitude of the slippage of anchor, mm.
7.6.4. If the largest and smallest dimensions of the disconnected part of the concrete from the anchor device to the boundaries of destruction on the surface of the structure are more than doubled, as well as if the depth of the breakdown is different from the depth of sealing anchor device by more than 5% (for\u003e 0.05ft, U\u003e 1.1), the test results are allowed to take into account only for the approximate assessment of concrete strength.
Note - Approximate values \u200b\u200bof concrete strength are not allowed to be used to assess the grade of concrete for strength and constructing calibration dependencies.
7.6.5 Test results are not taken into account if the depth of the pulp differs from the depth of sealing the anchor device more than 10% (for\u003e 0.1 A) or the fittings were naked at a distance of an anchor device, less than the depth of its sealing.
7.7 Rib Ribbon
7.7.1 When testing the rib ribbling method on the test section, there should be no cracks, concrete glands, inapplications or shells with a height (depth) of 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.
7.7.2 Testing is carried out in the following sequence:
Purge detection device. Apply the load capacity of theulicavvv (1 ± 0.3) kN / s;
Fix the testing of the seloimerizer of the device;
Measure the actual depth of the rock;
Determine the average value of the brightness.
7.7.3 Test results are not taken into account, if concrete has been proponged. The marmatura or the actual bright depth differed from the more than 2 mm specified.
8 Processing and design results
8.1 Test results are present in the table in which:
Type of design;
Design class of concrete;
Age of concrete;
Concrete strength of each projected section 7.1.5;
The average strength of concrete design;
Design zones or its parts subject to requirements 7.1.1.
The form of the test results table is shown in Appendix K.
8.2 Processing and assessment of compliance with the established requirements for the values \u200b\u200bof the actual strength of concrete obtained using the methods of methods given in this standard, 6105 is carried out.
PR and M in H in N and B - statistical assessment of the class of concrete based on test results are carried out according to GOST 18105 ("A" scheme. "B" or "B") in cases where concrete strength is determined by the calibration dependence built in In accordance with section 6. When using previously established dependencies by binding them (by Appendix G), statistical control is not allowed, and the assessment of the class of concrete is carried out only according to the GOST 18105 scheme.
8.3 The results of determining the strength of concrete Mechanical methods of non-destructive testing are issued in the conclusion (protocol) in which the following data leads:
About tried structures with an indication of the project class, the date of concreting and testing or age of concrete at the time of testing;
On the applied methods for monitoring the strength of concrete;
About the types of devices with factory numbers, information about the calibration of devices;
On adopted calibration dependences (equation of dependence, parameters of addiction, compliance with the conditions for the use of calibration dependence);
Used to build a calibration dependence or its binding (date and test results of non-destructive indestructible and direct or destructive methods, corrective coefficients);
On the number of sections of determining concrete strength in structures with their location;
Test results;
Methodology, results of processing and evaluation of the obtained data.
Standard Test Scheme by Rockwing
A.1 Standard test diagram by the method of separation with the creation provides for testing under the compliance with the requirements of A.2-A.6.
A.2 Standard test diagram Applicable in the following cases:
Heavy Concrete Tests with compression strength from S to 100 MPa:
Tests of lightweight concrete compressive strength from S to 40 MPa:
The maximum fraction of large concrete aggregate is no more working depth of sealing anchor devices.
A.C. Supports of the loading device uniformly lay down to the surface of concrete at a distance of at least 2H from the axis of the anchor device, where L is the working depth of the anchor device. The test scheme is shown in Figure A.1.
1 - a device with a loading device and a silica; 2 - Support Loading Device: 3 - Capture of the loading device: 4 - transition elements, traction, S - anchor device. 6 - Embossed concrete (cone): 7 - Test design
Figure A.1 - Scheme of testing by the method of separation with the rock
A.4 Standard Test Scheme by the method of separation with the crease, the use of three types of anchor devices is provided (see Figure A.2). Anchor device Type I is installed in construction during concreting. Anchor devices of types II and ILL are installed in the hole prepared in the design.
1 - working rod: 2 - working rod with rami different cone: 3 - segment corrugated shoes: 4 - Laying rod: 5 - work rod rod with a ripe expansion cone: B - leveling washer
Figure A.2 - Types of anchor devices for standard test diagram
A.5 The parameters of the anchor devices and the values \u200b\u200bof them are valid for them measured concrete strength with a standard test diagrater are shown in Table A.1. For lightweight concrete, only anchor devices with an embedding depth of 48 mm are used for the standard test diagram.
Table A.1 - Anchor Device Parameters with Standard Test Scheme
|
Type of anchor device |
The diameter of the TF anchor device. MM. |
Depth of sealing anchor devices, mm |
Valid DDA Anchor Device Measurement Range of Concrete Compression Measurement. MPa |
||
|
babies H. |
full l " |
heavy | |||
A.B Design Anchors of Types II and III should provide a preliminary (before the load application), comprise the walls of the opening at the working depth of the sealing l and control slippage after the test.
Standard Test Scheme Rib Rib
B.1 Standard test diagram The rib ribbon method provides for testing when complying with B.2-B.4 requirements.
B.2 Standard Test Scheme Applicable in the following cases:
The maximum fraction of large concrete aggregate is not more than 40 mm:
Heavy concrete tests with compression strength from 10 to 70 MPa on granite and limestone crushed. B.z for testing applies a device consisting of a power excliter with a block of Silia
rigel and gripper with a bracket for local ribs of construction. The test scheme is shown in Figure B.1.
1 - device loading device and sipheyer. 2 - Support frame: 3 - Caulible concrete: 4 - Test
design ^ - Capture with a brass
Figure B.1 - Test Scheme by Rib Ribbon
B.4 When the edge of the ribs must be provided with the following parameters:
The depth of the grinding A ■ (20 A 2) mm.
Rocking width 0 "(30 A 0.5) mm;
The angle between the direction of the load and the normal to the loaded surface of the structure P »(18 A 1) *.
Graduation dependence for the separation method with the rocking with the standard test diagram
When conducting tests by the method of separating with bilgery according to the standard scheme, according to the application and the cubic strength of the concrete is not compression of R. MPa. It is allowed to calculate according to the grindoocale dependence by the formula
I * P) | P\u003e ^. (IN 1)
where t, - the coefficient, which takes into account the maximum size of a large aggregate in the zone of the exhaustion and taken equal to 1 with the size of the aggregate size of less than 50 mm:
t 2 - The ratio of proportionality for the transition from the effort of the breakdown in the kilonutytones to the strength of concrete in megapascals:
The reveal of an anchor device. kn.
When testing heavy concrete, the strength of 5 MPa and more and easily concrete strength from 5do40mp The value of the proportionality coefficient T 2 is received according to Table B.1.
Table 8.1.
|
Type of anchor device |
The range of measured concrete strength on compression. MPa |
The diameter of the anchor device d. n. |
Depth of embedding anchor device, mm |
The value of the coefficient sh ^ for concrete |
|
|
heavy | |||||
The coefficients T 3 when testing heavy concrete with medium strength above 70 MPa should be taken according to GOST 31914.
Graduation dependence for the rib of ribs with a standard test diagram
When performing the finishing of the edge of the ribs according to the standard diagram according to the application b, the cube strength on the compression of concrete on the granite and lime crushed it is R. MLA. It is allowed to calculate by graduation dependence by the formula
R - 0.058m (30p + p j). (G.1)
where T is a coefficient that takes into account the maximum size of a large aggregate and is taken to be equal to:
1.0 - with aggregate size less than 20 mm:
1.05 - with filler size from 20 to 30 mm:
1.1 - ConcompliancePillars30mm:
P is the effort of the Rocking. kn.
Appaced (mandatory)
Requirements for mechanical testing
Table D.1
|
Name characteristics of devices |
Device characteristics for method |
|||||||||||||||||||||||||||||||||||||
|
elastic |
shock impulse |
plastic deformations |
oramaa from Skapaaa * and him |
|||||||||||||||||||||||||||||||||||
|
Hardness of the drummer, Boyhead or Indenter Nyas. no less | ||||||||||||||||||||||||||||||||||||||
|
Roughness of the contact part of the drummer or indenter. μm. no more | ||||||||||||||||||||||||||||||||||||||
|
The diameter of the drummer or indenter. mm. no less | ||||||||||||||||||||||||||||||||||||||
|
The thickness of the edges of the disk indenter. mm. no less | ||||||||||||||||||||||||||||||||||||||
|
The angle of the conical indenter | ||||||||||||||||||||||||||||||||||||||
|
The diameter of the imprint,% of the diameter of the indenter | ||||||||||||||||||||||||||||||||||||||
|
Perpendicularity tolerance when applying a nvloader is not a height of 100 mm. MM. | ||||||||||||||||||||||||||||||||||||||
|
Energy impact. J. Not less | ||||||||||||||||||||||||||||||||||||||
|
Load increase speed. KN / S. | ||||||||||||||||||||||||||||||||||||||
|
Load measurement error, C. No more |
5 Here rjn - see explication to the formula (£ .3). After rejection, the calibration addiction is set again by formulas (£ .1) - (E.S) according to the remaining test results. The rejection of the remaining test results is repeated, considering the implementation of the condition (E.6) when using a new (adjusted) graduation dependence. Private concrete strength values \u200b\u200bmust meet 6.1.7 requirements. £ .3 Parameters of calibration dependence For adopted calibration dependences, they define: The minimum and maximum values \u200b\u200bof the indirect characteristic H gave. RMS deviation ^ n m constructed graduation dependence according to the formula (E.7); Correlation coefficient of calibration dependence G by formula
where the average value of concrete strength on gradual dependence is calculated by the form
here the values \u200b\u200bR (h. I am F.Y F. N - see explication to formulas (E.EE). (E.B). E.4 Correction of calibration dependence The adjustment of the installed calibration dependence taking into account additionally the resulting test results should be carried out at least once a month. When adjusting a calibration dependency to existing test results, at least three new results obtained with minimal, maximum and intermediate values \u200b\u200bof the indirect indicator are added. As data accumulates to build a calibration dependence, the results of previous tests. Starting from the very first, rejected so that the total number of results does not exceed 20. After adding new results and the rejection of the old minimum and maximum values \u200b\u200bof the indirect characteristic, the calibration dependence and its parameters are set again by formulas (E.1) - (E.9). E.S Conditions for the use of calibration dependence The use of calibration dependences to determine the strength of the concrete for the present standard is allowed only for the values \u200b\u200bof the indirect characteristic falling in the range from H TL BC. If the correlation coefficient G< 0.7 или значение 5 тнм "Я ф > 0.15. That monitoring and assessment of strength on the dependency obtained is not allowed. Conditional Dependency Binding Method G.1 The value of concrete strength, determined using the calibration dependence mounted for concrete, differing from the subject, is multiplied by the coincidence coefficient to C. The value is calculated by the form where - the strength of concrete in the T-M site determined by the separation method by scorching or testing cores polishing 26570; I am MESa - concrete strength in<-м участке, опредепяемвя пюбым косвенным методом по используемой градуировочной зависимости: л - число участков испытаний. G.2 When calculating the coincidence coefficient, conditions must be observed: The number of test sections taken into account when calculating the coincidence coefficient, P i 3; Each particular value of me to, / I (0 ^ should be at least 0.7 and not more than 1.3: Each particular value I ^. must differ from the average no more than 15%: Values \u200b\u200bare not satisfying conditions (w.2). (Zh.z). should not be taken into account when calculating coefficient coincidence to p. Appointment of the number of sections of tests of prefabricated and monolithic structures And.1 In accordance with GOST 18105, when monitoring the strength of the concrete of prefabricated structures (selling or redoubted), the CNSLO of the controlled structures of each species takes no less than one of the structures from the party. If the party consists of 12 constructions and less, conduct solid control. At the same time, the number of participants should be at least: 1 Not 4 m Length of linear structures: 1 on 4 m 2 squares of flat designs. And.2 In accordance with GOST 18105, when monolithic concerns monolithic structures are monitored at an intermediate age, nevertheless methods control at least one design of each species (column, wall, overlap, and beam, etc.) from the controlled batch. I.W. In accordance with GOST 18105, when monolithic concerns monolithic strength monitoring at design age, a continuous nerve control of the strength of the concrete of all the designs of the controlled batch is carried out. At the same time, the number of test sections should be at least: 3 for each invapination for flat designs (wall, overlapping, foundation plate); 1 to 4 m lengths (or 3 on the capture) for each linear horizontal design (beam, riglels); 6 For each design - for linear vertical structures (column, pylon). The total number of measurements for calculating the characteristics of the homogeneity of the concrete strength of the batch of structures should be at least 20. And 4. The number of single measurements of concrete strength with mechanical methods of nervous control on each site (the number of measurements on the site) is received by table 2. Test results presentation table form
UDC 691.32.620.17:00 6.354 μs 91.100.10 NEQ Keywords: structural heavy and lightweight concrete, monolithic and prefab concrete and iron * concrete products, designs and structures, mechanical methods for determining compression strength, elastic rebound, impact pulse, plastic deformation, separation, ribbing, chuck Editor TT Martynova Technical Editor 8.N. Prussakova Corrector M 8. Vuchaya Computer Layout I.A. Napacking Rent in the set on 12/29/201S. Signed and printing 06.02 2016. Format 60 "64 ^. Headset Arial. Hood. Pechs. l. 2.7B. Uad. l. 2.36. Tire "60 ECE. Zack. 263. Published and imprinted in FSUE "Standinform", $ 12399 Moscow. Grenade lane. 4. | |||||||||||||||||||||||||||||||||||||
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
By the decision of the State Committee of the Council of Ministers of the USSR on the construction of September 22, 1977 No. 128, the deadline for administration was 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 for the methods for determining its compressive strength in products and designs of mechanical action to rebound, plastic deformation, the ribs of the design and 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 result by non-destructive method of the structure of the structure.
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 of 0; Ai h is calculated by formulas.
# 0 - R- (I \\ '//, * (3)
"\u003d '-H? -Z-: (4)
2 (HI-77) (in ri-uir)
| B n \u003d c ^ - b ". |
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
| Number series |
H, divisions |
Serin number |
W, division |
R, kgf / cm » |
|
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
| Series number 1. |
Sample numbers; | |
Numbers Test Points |
/? , Kgosl1 * |
|||
Page, 8 GOST 22690.0-77
Continued
| Rooms seried 1. |
Sample numbers / |
Numbers Test Points |
RJ T KTS / CM 3 |
f U Max ** min " |
||
| 16.9 17.5 18.8 19.0 18.2 cf. 18,1 |
||||||
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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