1 Scope
This document specifies the classification and performance classes of high performance concrete. General requirements, raw materials, mix ratio, quality requirements, preparation, test methods inspection rules, order and delivery.
This document applies to industrial and civil buildings, municipalities, railways, highways, water transport. Marine, water conservancy, energy and other construction projects with high performance concrete.
2 normative reference documents
The contents of the following documents constitute the essential provisions of this document through the normative references in the text. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; do not note the date of the reference document, its latest version (including all the revision of the list) applies to this document.
GB 175 General-purpose silicate cements
GB/T 176 Methods of chemical analysis of cement
3 Terminology and definitions
The following terms and definitions apply to this document.
3.1
High performance concrete
With the overall objective of specific requirements for concrete performance in the design, construction and use of construction projects, high quality conventional raw materials are selected, admixtures and mineral admixtures are reasonably added, lower water-cement ratios are used and the mix ratios are optimized, and concrete with excellent mix properties, mechanical properties, durability and long-term performance is made through ready-mix and green production methods and strict construction measures.
[Source: JGJ/T385-2015, 2.0.1]
3.2
Conventional crystal high performance concrete ordinary high performance concrete
Concrete that meets the technical requirements of high performance concrete and is used routinely, except for special product high performance concrete.
[Source:JGJ/T385-2015,2.0.3]
3.3
Special crystal high-performance concrete special high performance concrete
Light-aggregate concrete, high-strength concrete, self-compacting concrete, fibrous concrete that meets the technical requirements of high-performance concrete.
[Source:JGJ/T385-2015,2,0.2]
4 Classification and performance classes
4.1 Classification
4.1.1 Conventional product high performance concrete
Conventional high performance concrete shall be high performance concrete other than the special product high performance concrete specified in Table 1, code A, concrete strength grade code C.
4.1.2 Special product high performance concrete
The types of special product high performance concrete and their designations shall be in accordance with the provisions of Table 1.
4.2 Performance classes
4.2.1 Mix performance grades
High-performance concrete mix slump, expansion grade classification and allowable deviation should be consistent with the provisions of GB50164....
4.2.2 Strength grade
4.2.2.1 The strength grade of conventional high-performance concrete shall be divided into C30, C35, C40, C45, C45 and C55 according to the standard value of cubic compressive strength.
C50, C55.
4.2.2.2 The strength classes of high strength high performance concrete shall be classified according to the standard values of cubic compressive strength as C60, C65, C70, C75, C80, C85, C90, C95, C100, C105, C110 and C115.
4.2.2.3 The strength classes of self-compacting high performance concrete shall be classified according to the standard values of cubic compressive strength as C30.C35, C40, C45, C50, C55, C60, C65, C70, C75, C80, C85, C90, C95, C100, C105, C110 and C115.
4.2.2.4 The strength classes of steel fibre high performance concrete shall be divided into CF35.CF40, CF45, CF50, CF55, CF60, CF65, CF70, CF75, CF80CF85, CF90, CF95.CF100, CF105, CF110, CF115 according to the standard values of cubic compressive strength; synthetic fibre high performance The strength classes of concrete shall be classified according to the standard values of cubic compressive strength as C30, C35.C40, C45.C50, C55, C60, C65, C70, C75.C80.
42.2.5 The strength class of high performance concrete used for precast products shall not be less than C40, except for light aggregate high performance concrete.
4.2.3 Durability grades.
4.2.3.1 The frost resistance of high performance concrete shall be classified as F250, F300, F350, F400 and greater than F400.
4.2.3.2 Water penetration resistance classes for high performance concrete are classified as P12 and greater than P12.
4.2.3.3 High performance concrete is classified as KS120, KS150 and greater than KS150 for resistance to sulphate attack.
5 General requirements
5.1 The class of the environment in which the project is located and the level of action should be determined according to GB/T50476.
5.2 When the concrete structure has special anti-cracking and anti-seepage requirements, a special demonstration should be made.
5.3 When the concrete structure has high requirements for crack resistance, high performance concrete should be made of cement with small specific surface area, slow heat release, low heat of hydration, slow early strength development and low shrinkage.
5.4 The evaluation of high performance concrete should be carried out in accordance with the provisions of JGJ/T385.
5.5 The construction of high performance concrete shall conform to the provisions of Appendix A.
5.6 Light aggregate high performance concrete shall comply with the provisions of JGJ/T12JGJ/T385.
6 Raw materials
6.1 Cement
6.1.1 The choice of cement type and strength grade shall be based on the design. Construction requirements. The structural characteristics and the environmental and application conditions of the project shall be determined.
7 Fitting ratio
7.1 General requirements
7.1.1 The concrete proportion shall be designed to meet the properties of the concrete mix (8.1). The requirements for mechanical properties (8,2), durability and long-term performance (8.3).
7.1.2 The design of high-performance concrete mixes should pay attention to the quality of the aggregate and the design of the aggregate system, and in the case of meeting the mix performance and construction requirements, it is advisable to increase the amount of coarse aggregate as much as possible and design a lower mix fluidity.
7.1.3 The design of the mix ratio of conventional high performance concrete shall be in accordance with the provisions of JGJ55.
7.1.4 The design of high performance concrete for special products shall be in accordance with the following provisions:
a) High strength high performance concrete shall be designed in accordance with the provisions of JGJ55;
b) Self-compacting high performance concrete ratio design shall comply with the provisions of JGJ/T 283;
c) The proportional design of fibrous high performance concrete shall comply with the provisions of JGJ/T 221.
7.1.5 The slurry ratio of high performance concrete shall be in accordance with the provisions of Table 6.
8 Quality requirements
8.1 Mix performance requirements
8.1.1 High performance concrete mixes shall have good compatibility and the mix properties such as slump, expansion, slump loss by time and setting time shall meet the construction requirements.
8.1.2 A smaller slump is desirable provided that it meets the requirements of the construction process.
8.1.3 The maximum content of water-soluble chloride ions in high performance concrete mixes shall comply with the provisions of Table 16.
9 Preparation
9.1 General rules
9.1.1 The mixing plant (building) should comply with the provisions of GB/T10171.
9.2 Raw material intake and storage
9.2.1 Raw material intake and storage should be in accordance with the provisions of GB/T14902 and GB50164.
9.2.2 Bulk powder should not be used in bagged form.
9.2.3 Transportation of raw materials. Loading and unloading and storage should take measures to reduce noise and dust, and keep clean and hygienic, in line with environmental health requirements.
9.3 Measurement
9.3.1 Production measurement should be in accordance with the provisions of GB/T14902.
9.3.2 admixture measurement is appropriate to use a higher precision measurement equipment or other effective wipe to improve the accuracy of admixture measurement.
9.3.3 When special raw materials such as fibres are added, a person should be responsible for the operation and safety of the environment.
9.3.4 Dust emissions from the metering process should be strictly controlled and the dust removal device should be regularly replaced.
9.4 Mixing
9.4.1 Mixing shall be in accordance with the provisions of GB/T14902.GB50164.
9.4.2 Compulsory mixers should be used. It is advisable to use other mixing equipment such as vibratory mixing to make the material more evenly dispersed. Better mixing effect of mixing equipment.
9.4.3 Mixing process should be determined according to the concrete ratio, mixing equipment, etc.
9.4.4 The temperature of the powder material for the production of high performance concrete should not be higher than 60C.
9.4.5 The following control measures shall be taken for the temperature of the mix:
a) When mixing concrete during winter construction, it is advisable to use the method of heating water to increase the temperature of the mix, and also the method of heating the aggregate to increase the temperature of the mix;
b) When mixing concrete in the hot season, measures such as shade spraying and air cooling should be taken to reduce the temperature of the aggregate; cold water or ice chips can be used to reduce the temperature of the mix when mixing concrete.
9.5 Transport
9.5.1 Transport should be in accordance with the provisions of GB/T14902.GB50164 and GB 50666.
9.5.2 It is advisable to use recycled water to wash the mixer trucks when entering or leaving the plant to maintain hygiene and cleanliness.
9.5.3 No water should be added to high performance concrete during transport.
10 Test methods
10.1 Cement properties
10.1.1 The specific surface area shall be determined according to the method of GB/T8074.
10.1.23d compressive strength 28d compressive strength should be determined according to the method of GB/T17671, 28d/3d compressive strength ratio is the ratio of 28d compressive strength to 3d compressive strength.
11 Inspection rules
12 Order and delivery
Appendix A (normative) Construction of high performance concrete
1 Scope
2 normative reference documents
3 Terminology and definitions
4 Classification and performance classes
5 General requirements
6 Raw materials
7 Fitting ratio
8 Quality requirements
9 Preparation
10 Test methods
11 Inspection rules
12 Order and delivery
Appendix A (normative) Construction of high performance concrete
