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Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
Concrete Strength Inspection and Assessment Standard
GBJ107—87
Engineering Construction Standard Full-text Information System
W Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
Concrete Strength Inspection and Assessment Standard
107—87
Editing Department: Ministry of Urban and Rural Construction and Environmental Protection of the People's Republic of ChinaApproving Department: State Planning Commission of the People's Republic of ChinaEffective Date: March 1, 1988
Engineering Construction Standard Full-text Information System
Engineering Construction Standard Full-text Information System
Notice on Issuing the "Concrete Strength Inspection and Assessment Standard" No. 1140 of the State Planning Commission [1987]
In accordance with the requirements of the State Planning Commission's Document No. 305 [1984], the "Concrete Strength Inspection and Assessment Standard" jointly formulated by the Ministry of Urban and Rural Construction and Environmental Protection and relevant departments has been reviewed by relevant departments. The "Standard for Testing and Evaluation of Concrete Strength" (GBJ107-87) is hereby approved as a national standard, which will be implemented on March 1, 1988. After the implementation of this standard, the relevant provisions of the current "Code for Construction and Acceptance of Reinforced Concrete Engineering" (GBJ20483) on testing and evaluating concrete strength and selecting concrete mix strength will be automatically abolished.
This standard is managed by the Ministry of Urban and Rural Construction and Environmental Protection, and its specific interpretation and other work are the responsibility of the China Academy of Building Research. The publication and distribution is organized by the Institute of Standards and Norms of Capital Construction of our Commission.
State Planning Commission
July 9, 1987
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Preparation Instructions
This standard is prepared by the China Academy of Building Research in conjunction with 12 units including Beijing Construction Engineering Corporation in accordance with the requirements of the State Planning Commission's Document No. 305 [1984].
During the preparation process, we conducted extensive investigations and systematic experimental studies on the quality status of concrete nationwide and issues related to concrete strength inspection and evaluation, absorbed effective scientific research results, and drew on relevant foreign standards. After soliciting opinions from relevant units nationwide and conducting pilot applications, the draft was finalized at the national review meeting. This standard is divided into four chapters and five appendices. The main contents include: general principles, general provisions, concrete sampling, specimen preparation, maintenance and testing, concrete strength inspection and evaluation, etc.
In the process of implementing this standard, please pay attention to accumulating information and summarizing experience. If you find that there is a need for modification or supplementation, please send your opinions and relevant information to the Structure Institute of China Academy of Building Research for reference in future revisions. Urban and Rural Construction Environmental Protection Department
May 1987
Engineering Construction Standard Full Text Information System
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Chapter 1 General
Chapter 2
Chapter 3
Chapter 4
General provisions.
Sampling of concrete, preparation, maintenance and testing of test pieces Inspection and evaluation of concrete strength...
Section 1
Statistical method evaluation·
Section 2
Non-statistical method evaluation.
Section 3
Judgement of the conformity of concrete strength·
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Conversion relationship between concrete grade and concrete strength grade Concrete construction mix strength·
Concrete production quality level
Conversion relationship table between commonly used non-legal measurement units and legal measurement units···.··
Explanation of terms used in this standard
Additional explanation
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Chapter 1 General Provisions
Article 1.0.1 This standard is formulated in order to unify the inspection and evaluation methods of concrete strength, promote enterprises to improve their management level and ensure the quality of concrete strength. Article 1.0.2 This standard applies to the inspection and evaluation of the compressive strength of ordinary concrete and lightweight aggregate concrete.
For concrete with special requirements, the inspection and evaluation of its strength shall also comply with the relevant provisions of the current national standards.
Article 1.0.3 In addition to complying with the provisions of this standard, the inspection and evaluation of concrete strength shall also comply with the relevant provisions of the current national standards. Note: For projects designed in accordance with the "Code for Design of Reinforced Concrete Structures" (TJ10-74), when using this standard to inspect and evaluate concrete strength, the concrete grade used in the design shall be converted into concrete strength grade in accordance with the provisions of Appendix 1 of this standard. The mix strength during construction shall also be converted according to the same principle. Engineering Construction Standard Full-text Information System
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Chapter II General Provisions
Article 2.0.1 The strength grade of concrete shall be divided according to the standard value of cube compressive strength. The concrete strength grade is represented by the symbol C and the standard value of the cube compressive strength (in N/mm2).
Article 2.0.2 The standard value of the cube compressive strength refers to a value in the overall distribution of the compressive strength measured by the standard test method for a cube specimen with a side length of 150mm made and cured according to the standard method at the age of 28 days. The percentage of strengths lower than this value shall not exceed 5%.
Article 2.0.3 The strength of concrete shall be inspected and evaluated in batches. An acceptance batch of concrete shall consist of concrete with the same strength grade, the same age, and basically the same production process conditions and mix ratio. For cast-in-place concrete at the construction site, the acceptance batches shall be divided according to the acceptance items of the unit project, and each acceptance item shall be determined in accordance with the current national standard "Standard for Inspection and Evaluation of Construction Installation Engineering Quality". Article 2.0.4 Ready-mixed concrete plants, precast concrete component plants and construction units that use on-site centralized mixing of concrete shall evaluate the concrete strength according to the statistical method specified in this standard. For the concrete of prefabricated components produced sporadically or concrete mixed on site in small batches, the non-statistical method specified in this standard can be used for evaluation. Article 2.0.5 In order to meet the requirements of concrete strength grade and concrete strength evaluation, the appropriate concrete construction mix strength should be selected according to specific conditions such as raw materials, concrete production process and production quality level. The construction mix strength of concrete can be determined in accordance with the provisions of Appendix 2 of this standard and combined with the specific conditions of the unit. Article 2.0.6 Ready-mixed concrete plants, prefabricated concrete component plants and construction units that use on-site centralized mixing of concrete should regularly conduct statistical analysis of concrete strength to control concrete quality. The production quality level of concrete can be determined in accordance with the provisions of Appendix 3 of this standard.
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Chapter 3 Concrete Sampling, Preparation, Maintenance and Testing of Test Specimens
Article 3.0.1 Concrete specimens shall be randomly selected at the concrete pouring site, and the sampling frequency shall comply with the following provisions:
1. For every 100 plates of concrete with the same mix ratio, but not exceeding 100m3, the sampling frequency shall not be less than once.
2. For every less than 100 plates of concrete with the same mix ratio mixed by each work shift, the sampling frequency shall not be less than once.
Note: Ready-mixed concrete shall be sampled in the ready-mixed concrete plant in accordance with the above provisions. After the concrete is transported to the construction site, it shall still be sampled and inspected in accordance with the provisions of this article.
Article 3.0.2 Each group of three test specimens shall be sampled and made from the same plate of concrete. The determination of its representative strength value shall comply with the following provisions: 1. Take the arithmetic mean of the strength of the three specimens as the representative strength value of each group of specimens; 2. When the difference between the maximum or minimum strength value and the middle value in a group of specimens exceeds 15% of the middle value, take the middle value as the representative strength value of the group of specimens; 3. When the difference between the maximum and minimum strength values and the middle value in a group of specimens exceeds 15% of the middle value, the strength of the group of specimens shall not be used as the basis for evaluation. Article 3.0.3 When non-standard size specimens are used, their compressive strength shall be converted to the compressive strength of standard specimens. The conversion coefficient shall be adopted in accordance with the following provisions: 1. Take 0.95 for cubic specimens with a side length of 100mm; 2. Take 1.05 for cubic specimens with a side length of 200mm. Article 3.0.4 The total number of specimens to be made for each batch of concrete samples shall not only take into account the number of specimens required for concrete strength assessment as specified in Chapter 4 of this standard, but also the number of specimens required for testing the concrete strength during the construction phase of the structure or component. Article 3.0.5 The standard for concrete specimens used to test and assess concrete strength shall be the same as that for standard engineering construction standard full text information system
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The molding method, standard curing conditions and strength test methods shall all comply with the provisions of the current national standard "Test Methods for Mechanical Properties of Ordinary Concrete". Article 3.0.6 When testing the concrete strength of structures or components during demolding, removal from the pool, delivery from the factory, hoisting, prestressed tendon tensioning or release, and short-term loads during construction, the molding method and curing conditions of the test pieces shall be the same as those used in construction.
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Engineering Construction Standard Full-text Information System
Chapter 4 Inspection and Evaluation of Concrete Strength
Section 1 Evaluation by Statistical Methods
Article 4.1.1 When the production conditions of concrete can be maintained consistent for a long time and the strength variation performance of the same type of concrete remains stable, an acceptance batch shall be composed of three consecutive groups of test pieces, and their strength shall meet the following requirements at the same time: mfau≥feu.k+0.7oo
feu,mln ≥fcu,k — 0. 70o
(4. 1. 1—1)
(4.1.1—2)
When the concrete strength grade is not higher than C20, its minimum strength shall also meet the following requirements:
f cu,min ≥0. 85f eu,k
(4.1.1—3)
When the concrete strength grade is higher than C20, its minimum strength shall still meet the following requirements:
f cu,min ≥0. 90f cu,k
(4.1.1—4)
Wherein: mf. —mean value of compressive strength of concrete cube of the same acceptance batch (N/mm2);
fea,k—standard value of compressive strength of concrete cube (N/mm2); go—standard deviation of compressive strength of concrete cube of the same acceptance batch (N/mm2);
feu,mtn
minimum value of compressive strength of concrete cube of the same acceptance batch (N/mm2).
Article 4.1.2 The standard deviation of the compressive strength of the concrete cube of the acceptance batch shall be determined according to the strength data of the same type of concrete specimens in the previous inspection period according to the following formula:
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Engineering Construction Standard Full-text Information System
Where:
The difference between the maximum and minimum values of the compressive strength of the cube of the first batch of specimens;
The total number of batches of data used to determine the standard deviation of the compressive strength of the concrete cube of the acceptance batch.
Note: The above inspection period should not exceed three months, and the total number of batches of strength data during this period shall not be less than 15. Article 4.1.3 When the production conditions of concrete cannot be maintained for a long time, and the variability of concrete strength cannot be kept stable, or when there is not enough data for the same type of concrete in the previous inspection period to determine the standard deviation of the compressive strength of the acceptance batch of concrete cubes, an acceptance batch shall be composed of no less than 10 groups of test pieces, and its strength shall meet the requirements of the following formula at the same time: mfa-M8fa≥0.9feu.k
feu,min≥efeu,k
(4.1.3-1)
(4.1.3-2)
Where: Sta
-the standard deviation of the compressive strength of the same acceptance batch of concrete cubes, (N/mm2). When the calculated value of st is less than 0.06fa, take st0.06fak;
Enter 1, Enter 2-qualified determination coefficient, according to Table 4.1.3. Acceptable determination coefficient of concrete strength
Number of specimen groups
Article 4.1.4
Formula calculation:
The standard deviation sf of concrete cube compressive strength can be calculated according to the following?- nmjoa
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W.bzsoso:cOnEngineering Construction Standard Full-text Information System
W.bzsoso:cOnEngineering Construction Standard Full-text Information System
Where: feu,—cube compressive strength value of the i-th group of concrete specimens (N/mm); n—the number of groups of concrete specimens in an acceptance batch. Section 2 Evaluation by non-statistical methods
Article 4.2.1 When evaluating the strength of concrete by non-statistical methods, the retained strength shall meet the following requirements at the same time:
msa≥1.15feuk
fal,min≥0.95fa,k
(4. 2. 1-1)
(4.2.1-2)
Section 3 Qualification judgment of concrete strength Article 4.3.1 When the test results can meet the requirements of Article 4.1.1 or Article 4.1.3 or Article 4.2.1, the strength of the batch of concrete is judged to be qualified; when it cannot meet the above requirements, the strength of the batch of concrete is judged to be unqualified. Article 4.3.2 Structures or components made of unqualified batches of concrete should be identified. Unqualified structures or components must be dealt with in a timely manner. Article 4.3.3 When there is doubt about the representativeness of the strength of concrete specimens, the strength of concrete in the structure or component can be estimated according to the relevant standards by drilling specimens from the structure or component or by non-destructive testing methods. Article 4.3.4 The concrete strength of the structure or component during demoulding, removal from the pool, factory, hoisting, tensioning or release of prestressed tendons, and during short-term loads during construction should meet the design requirements or relevant provisions of the current national standards. Engineering Construction Standards Full Text Information System
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(4.1.3—1)
(4.1.3——2)
Where: Sta
--standard deviation of the compressive strength of concrete cubes in the same acceptance batch, (N/mm2). When the calculated value of st is less than 0.06fa, take st0.06fak;
In 1, In 2--qualified determination coefficient, taken according to Table 4.1.3. Acceptable determination coefficient of concrete strength
Number of specimen groups
Article 4.1.4
Formula calculation:
The standard deviation sf of concrete cube compressive strength can be calculated according to the following?- nmjoa
Engineering Construction Standard Full-text Information System
W.bzsoso:cOnEngineering Construction Standard Full-text Information System
W.bzsoso:cOnEngineering Construction Standard Full-text Information System
Where: feu,—cube compressive strength value of the i-th group of concrete specimens (N/mm); n—the number of groups of concrete specimens in an acceptance batch. Section 2 Evaluation by non-statistical methods
Article 4.2.1 When evaluating the strength of concrete by non-statistical methods, the retained strength shall meet the following requirements at the same time:
msa≥1.15feuk
fal,min≥0.95fa,k
(4. 2. 1-1)
(4.2.1-2)
Section 3 Qualification judgment of concrete strength Article 4.3.1 When the test results can meet the requirements of Article 4.1.1 or Article 4.1.3 or Article 4.2.1, the strength of the batch of concrete is judged to be qualified; when it cannot meet the above requirements, the strength of the batch of concrete is judged to be unqualified. Article 4.3.2 Structures or components made of unqualified batches of concrete should be identified. Unqualified structures or components must be dealt with in a timely manner. Article 4.3.3 When there is doubt about the representativeness of the strength of concrete specimens, the strength of concrete in the structure or component can be estimated according to the relevant standards by drilling specimens from the structure or component or by non-destructive testing methods. Article 4.3.4 The concrete strength of the structure or component during demoulding, removal from the pool, factory, hoisting, tensioning or release of prestressed tendons, and during short-term loads during construction should meet the design requirements or relevant provisions of the current national standards. Engineering Construction Standards Full Text Information System
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(4.1.3—1)
(4.1.3——2)
Where: Sta
--standard deviation of the compressive strength of concrete cubes in the same acceptance batch, (N/mm2). When the calculated value of st is less than 0.06fa, take st0.06fak;
In 1, In 2--qualified determination coefficient, taken according to Table 4.1.3. Acceptable determination coefficient of concrete strength
Number of specimen groups
Article 4.1.4
Formula calculation:
The standard deviation sf of concrete cube compressive strength can be calculated according to the following?- nmjoa
Engineering Construction Standard Full-text Information System
W.bzsoso:cOnEngineering Construction Standard Full-text Information System
W.bzsoso:cOnEngineering Construction Standard Full-text Information System
Where: feu,—cube compressive strength value of the i-th group of concrete specimens (N/mm); n—the number of groups of concrete specimens in an acceptance batch. Section 2 Evaluation by non-statistical methods
Article 4.2.1 When evaluating the strength of concrete by non-statistical methods, the retained strength shall meet the following requirements at the same time:
msa≥1.15feuk
fal,min≥0.95fa,k
(4. 2. 1-1)
(4.2.1-2)bzxZ.net
Section 3 Qualification judgment of concrete strength Article 4.3.1 When the test results can meet the requirements of Article 4.1.1 or Article 4.1.3 or Article 4.2.1, the strength of the batch of concrete is judged to be qualified; when it cannot meet the above requirements, the strength of the batch of concrete is judged to be unqualified. Article 4.3.2 Structures or components made of unqualified batches of concrete should be identified. Unqualified structures or components must be dealt with in a timely manner. Article 4.3.3 When there is doubt about the representativeness of the strength of concrete specimens, the strength of concrete in the structure or component can be estimated according to the relevant standards by drilling specimens from the structure or component or by non-destructive testing methods. Article 4.3.4 The concrete strength of the structure or component during demoulding, removal from the pool, factory, hoisting, tensioning or release of prestressed tendons, and during short-term loads during construction should meet the design requirements or relevant provisions of the current national standards. Engineering Construction Standards Full Text Information System
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