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Engineering Construction Standard Full Text Information System
Construction Industry Standard of the People's Republic of China JG/T3064—1999
Steel Fiber
Concrete
Steel Fiber Reinforced Concrete Construction Standard
Published on 1999-07-28
Implemented on 1999-12-01
Ministry of Construction of the People's Republic of China
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
JG/T3064—1999
Steel fiber concrete is a new type of composite material, which is widely used in engineering fields such as roads, airports, bridges, water conservancy, ports, railways, mines, tunnels, military, industrial and civil buildings. This standard is formulated to ensure the quality of steel fiber concrete, promote technological progress, meet the needs of engineering construction, and comprehensively manage the quality of steel fiber concrete. Appendix A and Appendix B of this standard are both standard appendices. This standard was proposed by the Standard and Quota Research Institute of the Ministry of Construction. This standard is managed by the China Academy of Building Research, the Ministry of Construction's construction engineering standard and technology management unit.
The main drafting units of this standard are: Dalian University of Technology, and the Air Force Engineering Design and Research Bureau of the Chinese People's Liberation Army. Participating drafting units: the Ministry of Railways Science Research Institute, Southeast University, Beijing Municipal Design and Research Institute, and Zhejiang Jiaxing Qixing Steel Fiber Factory. The main drafters of this standard are: Zhao Guofan, Wang Zhangshui, Huang Chengkui, Xu Yunxian, Sun Wei, Luo Baoheng, and Chen Mo.
This standard is entrusted to Dalian University of Technology for interpretation. Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Construction Industry Standard of the People's Republic of China Steel Fiber Reinforced Concrete
Steel fiber reinforced concrete1Scope
JG/T3064—1999
This standard specifies the requirements for raw materials of steel fiber concrete, strength and durability of steel fiber concrete, mix ratio of steel fiber concrete, construction quality control of steel fiber concrete, test methods and inspection rules.
This standard is applicable to steel fiber concrete with a steel fiber volume ratio of not more than 3%. Cited Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T228—1987Metal tensile test method
7Concrete admixtures
GB8076—1997
GB50204—1992Code for construction and acceptance of concrete structure engineeringGBJ80—1985
GBJ81——1985
GBJ82——1985
GBJ97—1987
GBJ107—1987
JGJ63-1989
Test method for properties of ordinary concrete mixturesTest method for mechanical properties of ordinary concrete
Long-term performance and durability of ordinary concrete Energy test method Cement concrete pavement construction and acceptance specification Concrete strength inspection and evaluation standard
Concrete mixing water standard
Approved by the Ministry of Construction of the People's Republic of China on July 28, 1999 Engineering Construction Standard Full Text Information System
Implementation on December 1, 1999
Engineering Construction Standard Full Text Information System
JGJ/T551996
3 Definitions and symbols
Technical specification for ordinary concrete mix design 3.1 This standard adopts the following definitions:
3.1.1 Steel fiber steelfber
Short fiber made of processed steel material. 3.1.2 Steel fiber concrete steelfiberreinforced concrete Concrete with cement as binder reinforced with a certain amount of randomly distributed steel fibers.
3.1.3 Steel fiber volume ratio
steel fiberfraction in volume The percentage of steel fiber in the volume of steel fiber concrete. This standard uses the following symbols:
3.2.1d: Steel fiber diameter or equivalent diameter, mm. 3.2.24: Steel fiber length or nominal length, mm. 3.2.3
l/d: Steel fiber aspect ratio or nominal aspect ratio. 3.2.4P: Steel fiber volume ratio, %.
3.2.5f: Steel fiber tensile strength, MPa. 3.2.6fn, k, standard value of tensile strength of steel fiber concrete, MPa. 3.2.7f: Standard value of tensile strength of concrete determined in accordance with the provisions of the current relevant concrete structure code corresponding to the strength grade of steel fiber concrete, MPa. 3.2.8fm: Design value of flexural tensile strength of steel fiber concrete, MPa. 3.2.9fm: Design value of flexural tensile strength of plain concrete with the same water-cement ratio and raw materials as steel fiber concrete, MPa.
4 Raw materials of steel fiber concrete
4.1 Steel fiber
4.1.1 Product classification
1) Steel fiber can be divided into: cut-type steel fiber, shear-type steel fiber, 2
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melt-drawn steel fiber and milling steel fiber according to the production process. 2) The cross section of the steel fiber can be circular, rectangular, crescent-shaped and irregular. 3) The shape of the steel fiber can be straight and shaped. The shaped steel fiber can be wavy, indented, twisted, hooked and big-headed. 4.1.2 Steel fiber size
1) The nominal length of the steel fiber refers to the straight-line distance between the two end points of the steel fiber. Its size can be 15~60mm.
2) The diameter or equivalent diameter of the steel fiber cross section should be 0.3~1.2mm. 3) The aspect ratio or nominal aspect ratio of steel fiber should be between 30 and 100. 4) Other specifications and models can also be supplied according to the requirements of the purchaser. 4.1.3 Technical requirements and inspection methods
1) Length
The deviation between the length of steel fiber and its nominal value shall not exceed ±10%. Inspection method: Randomly sample 10 pieces from each batch of products and measure their length with a caliper with an accuracy of not less than 0.02mm. The qualified rate of length deviation shall not be less than 90%, and the average value of the length of 10 fibers shall also meet the deviation requirements. 2) Diameter or equivalent diameter
The deviation between the average diameter or equivalent diameter of steel fiber and its nominal value shall not exceed ±10%.
For the inspection of the diameter of circular cross-section steel fiber, randomly sample 10 pieces from each batch and measure their diameters one by one with a vernier caliper (the unit of measurement is mm, the accuracy is 0.02mm). The deviation between the average diameter and its nominal value shall meet the requirements of the specified deviation. The equivalent diameter of steel fibers with non-circular cross-sections is tested by mass method to determine the average equivalent diameter. 100 steel fibers are randomly sampled from each batch, and their mass is measured with a balance with an accuracy of 0.01g. The length of each steel fiber is measured with a vernier caliper with an accuracy of 0.02mm. The deviation between the average value d of the equivalent diameter obtained by formula (1) and its nominal value shall meet the specified deviation requirements.
d,0.113wp/tay
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Engineering Construction Standard Full-text Information System
In the formula: 2%——the measured mass of 100 steel fibers, g, la——the measured average length of the sampled steel fibers, mm; y——the mass density of steel 0.00785g/mm. 3) Aspect ratio
The deviation of the aspect ratio of steel fiber from its nominal value shall not exceed 10%. The deviation of the aspect ratio average value obtained based on the measured average length and the measured average diameter or equivalent diameter from its nominal value shall meet the requirements of the specified deviation. 4) Shape qualification rate
The percentage of the number of special-shaped steel fibers that meet the factory-specified shapes to the total number of fibers is called the shape qualification rate.
Except for straight steel fibers, the shape qualification rate of steel fibers of other shapes should not be less than 90%.
100 steel fibers are randomly sampled from each batch of products, and their shapes are checked one by one. If there are broken hooks, unilateral forming and other shape defects, they are considered unqualified. The shape qualification rate of the inspected steel fibers should not be less than 85%.
5) Tensile strength
The tensile strength of steel fibers shall not be less than 380MPa. When there are special requirements for the project, the tensile strength of steel fibers can be proposed by the purchaser based on technical and economic conditions. Ten pieces of products are randomly sampled from each batch for tensile strength test according to GB/T228 test method. The average tensile strength measured shall not be lower than the specified value, and the tensile strength of a single steel fiber shall not be lower than 90% of the specified value. When the parent material is a steel plate or steel wire, a large sample of the parent material can be used for the test, and the tensile strength of any sample measured shall not be lower than the specified value.
When conducting the tensile strength test of steel fibers, if the cross section of the sample is circular or rectangular, a vernier caliper with an accuracy of 0.01mm shall be used for measurement. The unit of cross-sectional area is mm2, and the calculation shall be retained to four decimal places. When the cross section of the sample is irregular, the cross-sectional area of the sample is determined by the length and mass of the fiber, and the mass of the steel fiber is weighed using a balance with an accuracy of 0.0001g. The tensile strength of steel fiber is calculated according to formula (2): fn = Fmex/ A
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(2)
Engineering Construction Standard Full Text Information System
Where: Fm—the maximum tensile load of the steel fiber tensile test, N; A——the actual area of the steel fiber cross section, mm2. 6) Bending performance
Steel fiber should be able to withstand 90° bending along a 3mm diameter steel rod without breaking. Ten steel fibers are randomly sampled from each batch of products, and each is manually bent 90° once along the circumference of a 3mm diameter steel rod. At least nine samples should not break. 7) Impurities
The surface of the steel fiber shall be free of oil stains and other impurities that hinder the bonding of the steel fiber with cement slurry. The total mass of adhesion pieces caused by poor processing, steel fibers with severe surface rust, rust powder and impurities contained in the steel fiber shall not exceed 1% of the mass of the steel fiber. 5kg of samples are randomly taken from each batch, and the surface of the steel fiber is inspected by naked eye. Adhesion pieces, severely rusted steel fibers and other impurities are manually picked and weighed. 8) The surface of the steel fiber shall not be plated with harmful substances or coated with coatings that are not conducive to bonding with concrete.
9) In addition to complying with the provisions of this standard, if the demander has other requirements for the steel fiber, the supply and demand parties may agree on additional technical conditions.
4.1.4 Inspection rules
1) Steel fibers shall be inspected in batches, and each batch shall be the same variety of products with the same material, size and technical specifications. Each supply of 5t or less than 5t is regarded as a batch and inspected according to the requirements of 4.1.3.
2) If any inspection result of the steel fiber does not meet the specified requirements, double samples shall be taken from the same batch of products for re-inspection of the unqualified items. If the re-inspection still fails, the batch of products shall be unqualified products.
4.1.5 Product Storage and Quality Certificate
1) Steel fiber products should be stored in a clean, ventilated and dry warehouse. Different types of steel fibers should be stored separately and not be invaded by rainwater and corrosive substances. 2) Each batch of delivered products should be accompanied by a quality certificate, which should indicate the manufacturer, product mark, delivery date, inspection documents and inspection department stamp. When the user has special needs, the chemical composition of the steel fiber material or the parent steel type should also be provided. 4.2 Other raw materials
4.2.1 The cement, water, aggregates, admixtures and mixed materials used should comply with the provisions of the current relevant standards and specifications on the raw materials used for concrete. 4.2.2 Seawater and sea sand shall not be used in mixing steel fiber concrete. The total chloride content in steel fiber concrete mixture shall not exceed 1% of the cement content for ordinary steel fiber concrete and reinforced steel fiber concrete in dry environment or with moisture-proof measures; for reinforced steel fiber concrete in moist environment without chloride ions or moist environment with chloride ions, it shall not exceed 0.3% and 0.1% of the cement content respectively; for prestressed steel fiber concrete and reinforced steel fiber concrete in corrosive environment, it shall not exceed 0.06% of the cement content.
4.2.3 The coarse aggregate particle size used in steel fiber concrete should not be greater than 20mm or 2/3 of the steel fiber length.
4.2.4 The performance of the admixture selected for mixing steel fiber concrete shall comply with the provisions of GB8076.
5 Strength and durability of steel fiber concrete
5.1 Strength grade of steel fiber concrete
The strength grade of steel fiber concrete shall be determined according to the standard value of cube compressive strength. The standard value of cube compressive strength refers to the compressive strength with a 95% guarantee rate measured by standard test method at 28 days of a cube specimen with a side length of 150 mm made and cured according to standard methods. If a cube specimen with a side length of 100 mm is used, its strength reduction factor is 0.95. The strength grade of steel fiber concrete is represented by the symbol CF. 5.2 Tensile strength of steel fiber concrete
5.2.1 The tensile strength of steel fiber concrete can be determined by multiplying the splitting tensile strength obtained by the test by the strength reduction factor 0.80. The splitting tensile strength test method shall be carried out in accordance with the provisions of GBJ81.
5.2.2 The standard value f of the tensile strength of steel fiber concrete can be determined according to formula (3): fak=f(1+α/d)
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+***** (3)
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Where: 4--The influence coefficient of steel fiber on the tensile strength of steel fiber concrete should be determined through experiments, or it can be taken according to the specified value of the current national steel fiber concrete structure design and construction regulations.
5.3 Flexural strength (flexural strength) of steel fiber concrete 5.3.1 When steel fiber concrete is used for highway pavement, airport pavement or other structures that use flexural strength as a design indicator, the classification and application range of the flexural strength design value of the base concrete corresponding to the steel fiber concrete can be adopted according to the provisions of the current national cement concrete pavement, airport pavement and other industry design specifications. 5.3.2 The design value fm of the flexural strength of steel fiber concrete can be determined according to formula (4): fm=fm(1+amA1/d)
****...*** (4)
Wherein: αm——the influence coefficient of steel fiber on flexural strength, which should be determined through experiments, or can be taken according to the specified value of the current national regulations on the design and construction of steel fiber concrete structures.
5.4 The test method for the frost resistance and impermeability of steel fiber concrete shall be carried out in accordance with the provisions of GBJ82. The measured frost resistance and impermeability index values shall not be lower than the design requirements. 6 Steel fiber concrete mix ratio
General requirements
In addition to meeting the general requirements of ordinary concrete, the mix ratio of steel fiber concrete shall also meet the requirements of tensile strength or flexural strength, toughness, workability of the mixture during construction, and non-agglomeration of steel fibers.
6.2 Selection of steel fiber
6.2.1 The selection of steel fiber varieties, geometric parameters and volume ratios shall meet the strength, toughness and durability of steel fiber concrete required by the design and shall meet the workability and construction requirements of the mixture. Improper selection shall not cause steel fiber agglomeration and blockage of concrete pumping pipes or injection pipes. The appropriate range of selection can be determined by referring to existing experience or the provisions of the current national regulations on the design and construction of steel fiber concrete structures. 6.2.2 For structures with corrosion resistance and high temperature resistance requirements, stainless steel fibers should be selected.
Engineering Construction Standard Full-text Information System
Engineering Construction Standard Full-text Information System
6.3 Steel Fiber Concrete Mix Design
6.3.1 The design of steel fiber concrete mix ratio can be carried out according to the following steps: 1) Determine the compressive strength and tensile strength or the compressive strength and flexural strength of the trial mix according to the strength standard value or design value and the strength improvement coefficient of the construction mix. The compressive strength improvement coefficient of the trial mix of steel fiber concrete mix ratio design shall be adopted in accordance with the provisions of JGJ/T55. The tensile strength improvement coefficient of the trial mix of steel fiber concrete can be adopted with reference to the compressive strength improvement coefficient. The flexural strength of the trial mix of steel fiber concrete can be determined according to the construction technology level and the importance of the project, at 1.10 to 1.15 times the design value of the flexural strength. 2) Calculate the water-cement ratio based on the compressive strength or flexural strength of the trial mix; 3) Determine the steel fiber volume ratio by calculation or based on existing data based on the tensile strength or flexural strength or toughness and durability requirements of the trial mix; 4) Determine the water consumption per unit volume based on the consistency required for construction through tests or existing data. If admixtures are added, the influence of admixtures should be considered; 5) Determine the sand ratio based on the consistency and steel fiber volume ratio or by referring to existing engineering experience; 6) Calculate the material consumption by the absolute volume method or the assumed mass density method to determine the preliminary mix ratio,
7) Conduct a performance test of the mixture based on the preliminary mix ratio, adjust the water consumption per unit volume and the sand ratio, and determine the benchmark mix ratio for the strength test. 8) Adjust the water-cement ratio and steel fiber volume ratio based on the strength test results to determine the construction mix ratio.
6.4 Comparative test
When it is necessary to evaluate the reinforcing and toughening effect of steel fiber on concrete, a comparative test mix ratio that meets the requirements of engineering design should be used in a special quality inspection unit. Under standard curing conditions, two groups of comparative tests of cube compressive strength, splitting strength, flexural strength, flexural toughness and flexural first crack strength should be carried out simultaneously in accordance with the provisions of GBJ81 and Appendix A (Appendix to the standard). The reinforcing and toughening effect of steel fiber on concrete should meet the requirements of engineering design.
When the manufacturer indicates the reinforcing and toughening effect of steel fiber on concrete in the product manual, the test mix ratio and test report should be provided at the same time, and data without test basis shall not be used.8
Engineering Construction Standard Full-text Information System
Engineering Construction Standard Full-text Information System
7 Quality control of steel fiber concrete construction
7.1 General requirements
Quality control of steel fiber concrete construction should include the inspection and measurement of each component material of steel fiber concrete, quality control of mixing, pouring and other processes. 7.2 Material inspection and measurement
7.2.1 The moisture content of coarse and fine aggregates should be measured during the construction process, not less than once per work shift. When the moisture content changes significantly, the number of times should be increased. According to the test results, the water consumption and material consumption should be adjusted in time.
7.2.2 During the construction period, the quality of various materials of steel fiber concrete should be calculated and determined according to the construction mix ratio and the amount of mixing at one time. The weighing deviation of the material shall not exceed the provisions of Table 1.
1 Material measurement deviation table
Material name
Allowable deviation
7.3 Mixing
Steel fiber
Cement or admixturebZxz.net
Coarse and fine aggregate
Admixture
7.3.1 The mixing of steel fiber concrete can be done by first dry mixing steel fiber with coarse and fine aggregate and cement, and then wet mixing with water, or by adding steel fiber during the mixing process.
7.3.2 After mixing steel fiber concrete, the uniformity and consistency of the mixture should be tested once per work shift (the deviation should not exceed ±10% of the mix ratio requirement), and the steel fiber volume ratio should be tested if necessary (the deviation should not exceed ±15% of the mix ratio requirement). The steel fiber concrete mixture mixed with air-entraining admixture should also be tested for its air content. The steel fiber concrete mixture should be mixed evenly and have a uniform color, and there should be no segregation, water seepage, or steel fiber agglomeration.
The consistency of steel fiber concrete mixture shall be expressed in slump or Vebe consistency. The slump method is applicable to mixtures with a slump value of not less than 20mm. The Vebe consistency method is applicable to mixtures with a slump value of 5 to 30s. The detection method shall be carried out in accordance with the consistency test method of GBJ80. The steel fiber volume ratio detection method shall be carried out in accordance with the provisions of Appendix B (Appendix to the standard). The air content detection method of steel fiber concrete mixtures with air-entraining admixtures shall be carried out in accordance with the GBJ80 mixture air content test. When it is necessary to test the water-cement ratio and cement content of steel fiber concrete, the detection method shall be carried out in accordance with the provisions of GBJ80 concrete mixture water-cement ratio analysis. 7.4 Casting
7.4.1 The casting of steel fiber concrete shall ensure the uniformity of steel fiber distribution and the continuity of the structure. During pouring, it is forbidden to add water due to dryness of the mixture. 7.4.2 Steel fiber concrete should be vibrated with a flat vibrator or an outside mold vibrator to ensure that the steel fiber concrete is dense and the uniform distribution of steel fibers should be ensured to avoid exposure of steel fibers on the surface of the structure.
7.5 Inspection of strength, bending toughness, frost resistance and impermeability 7.5.1 During construction, test pieces should be made according to the requirements of the project, and compressive strength, splitting tensile strength or bending tensile strength, bending toughness tests should be carried out. If there are special requirements, frost resistance and impermeability tests should also be carried out. The tests of compressive strength, splitting tensile strength and bending tensile strength shall be carried out in accordance with the provisions of GBJ81. The tests of bending toughness and bending initial crack strength shall be carried out in accordance with Appendix A. The frost resistance and impermeability tests shall be carried out in accordance with the provisions of GBJ82. 7.5.2 The specimen preparation, sampling method, and test method evaluation standard for the steel fiber concrete cube compressive strength test shall be carried out in accordance with the provisions of GB50204, GBJ81 and GBJ107 or relevant industry standards.
7.5.3 For steel fiber concrete used in projects such as highway pavements, airport pavements, industrial floors and dock pavements, the flexural tensile strength test of steel fiber concrete shall be carried out in accordance with the provisions of GBJ97 or relevant industry standards.
7.5.4 The specimen preparation, sampling method, and test method for the splitting tensile strength test of steel fiber concrete may refer to the provisions of GB50204 and GBJ107. And determine the tensile strength in accordance with 5.2.1.
The evaluation of the tensile strength of steel fiber concrete may refer to the provisions of GBJ107.
Engineering Construction Standards Full-text Information System3.1 The mixing of steel fiber concrete can be done by first dry mixing steel fiber with coarse and fine aggregates and cement, and then wet mixing with water, or by adding steel fiber during the mixing process.
7.3.2 After mixing steel fiber concrete, the uniformity and consistency of the mixture should be tested once per work shift (the deviation should not exceed ±10% of the mix ratio requirement), and the volume ratio of steel fiber should be tested if necessary (the deviation should not exceed ±15% of the mix ratio requirement). The air content of steel fiber concrete mixtures mixed with air-entraining admixtures should also be tested. Steel fiber concrete mixtures should be mixed evenly and have a uniform color, without segregation, water seepage, or steel fiber agglomeration.
The consistency of steel fiber concrete mixtures should be expressed in slump or Vebe consistency. The slump method is applicable to mixtures with a slump value of not less than 20 mm. The Vebe consistency method is suitable for mixtures of 5 to 30s. The detection method is carried out according to the consistency test method of GBJ80. The steel fiber volume ratio detection method shall be carried out according to the provisions of Appendix B (Appendix of the standard). The air content detection method of steel fiber concrete mixtures with air-entraining admixtures shall be carried out according to the GBJ80 mixture air content test. When it is necessary to test the water-cement ratio and cement content of steel fiber concrete, the detection method shall be carried out according to the GBJ80 concrete mixture water-cement ratio analysis provisions. 7.4 Casting
7.4.1 The casting of steel fiber concrete shall ensure the uniformity of steel fiber distribution and the continuity of the structure. During casting, it is prohibited to add water due to dryness of the mixture. 7.4.2 Steel fiber concrete should be vibrated with a flat vibrator or an outside mold vibrator to ensure that the steel fiber concrete is dense and the uniform distribution of steel fibers should be ensured to avoid the steel fibers being exposed on the surface of the structure.
7.5 Tests of strength, bending toughness, frost resistance and impermeability 7.5.1 During construction, test specimens should be made according to the requirements of the project to conduct compressive strength, splitting strength or bending strength, bending toughness tests. If there are special requirements, frost resistance and impermeability tests should also be conducted. The tests of compressive strength, splitting strength and bending strength shall be carried out in accordance with the provisions of GBJ81. The tests of bending toughness and bending initial crack strength shall be carried out in accordance with Appendix A. The frost resistance and impermeability tests shall be carried out in accordance with the provisions of GBJ82. 7.5.2 The preparation of test specimens, sampling methods, and test method evaluation standards for the cubic compressive strength test of steel fiber concrete shall be carried out in accordance with the provisions of GB50204, GBJ81 and GBJ107 or relevant industry standards.
7.5.3 For steel fiber concrete used in highway pavement, airport pavement, industrial ground and dock pavement, the bending and tensile strength test of steel fiber concrete shall be carried out in accordance with the provisions of GBJ97 or relevant industry standards.
7.5.4 The preparation, sampling and test methods of the steel fiber concrete splitting tensile strength test can refer to the provisions of GB50204 and GBJ107. And determine the tensile strength in accordance with 5.2.1.
The evaluation of the tensile strength of steel fiber concrete can refer to the provisions of GBJ107.
Engineering Construction Standards Full-text Information System3.1 The mixing of steel fiber concrete can be done by first dry mixing steel fiber with coarse and fine aggregates and cement, and then wet mixing with water, or by adding steel fiber during the mixing process.
7.3.2 After mixing steel fiber concrete, the uniformity and consistency of the mixture should be tested once per work shift (the deviation should not exceed ±10% of the mix ratio requirement), and the volume ratio of steel fiber should be tested if necessary (the deviation should not exceed ±15% of the mix ratio requirement). The air content of steel fiber concrete mixtures mixed with air-entraining admixtures should also be tested. Steel fiber concrete mixtures should be mixed evenly and have a uniform color, without segregation, water seepage, or steel fiber agglomeration.
The consistency of steel fiber concrete mixtures should be expressed in slump or Vebe consistency. The slump method is applicable to mixtures with a slump value of not less than 20 mm. The Vebe consistency method is suitable for mixtures of 5 to 30s. The detection method is carried out according to the consistency test method of GBJ80. The steel fiber volume ratio detection method shall be carried out according to the provisions of Appendix B (Appendix of the standard). The air content detection method of steel fiber concrete mixtures with air-entraining admixtures shall be carried out according to the GBJ80 mixture air content test. When it is necessary to test the water-cement ratio and cement content of steel fiber concrete, the detection method shall be carried out according to the GBJ80 concrete mixture water-cement ratio analysis provisions. 7.4 Casting
7.4.1 The casting of steel fiber concrete shall ensure the uniformity of steel fiber distribution and the continuity of the structure. During casting, it is prohibited to add water due to dryness of the mixture. 7.4.2 Steel fiber concrete should be vibrated with a flat vibrator or an outside mold vibrator to ensure that the steel fiber concrete is dense and the uniform distribution of steel fibers should be ensured to avoid the steel fibers being exposed on the surface of the structure.
7.5 Tests of strength, bending toughness, frost resistance and impermeability 7.5.1 During construction, test specimens should be made according to the requirements of the project to conduct compressive strength, splitting strength or bending strength, bending toughness tests. If there are special requirements, frost resistance and impermeability tests should also be conducted. The tests of compressive strength, splitting strength and bending strength shall be carried out in accordance with the provisions of GBJ81. The tests of bending toughness and bending initial crack strength shall be carried out in accordance with Appendix A. The frost resistance and impermeability tests shall be carried out in accordance with the provisions of GBJ82. 7.5.2 The preparation of test specimens, sampling methods, and test method evaluation standards for the cubic compressive strength test of steel fiber concrete shall be carried out in accordance with the provisions of GB50204, GBJ81 and GBJ107 or relevant industry standards.
7.5.3 For steel fiber concrete used in highway pavement, airport pavement, industrial ground and dock pavement, the bending and tensile strength test of steel fiber concrete shall be carried out in accordance with the provisions of GBJ97 or relevant industry standards.
7.5.4 The preparation, sampling and test methods of the steel fiber concrete splitting tensile strength test can refer to the provisions of GB50204 and GBJ107. And determine the tensile strength in accordance with 5.2.1.
The evaluation of the tensile strength of steel fiber concrete can refer to the provisions of GBJ107.
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