1.0.1 This standard is formulated in order to ensure the durability of concrete structures to fulfill the specified design working life and ensure the reasonable working life of engineering structures.
1.0.2 This standard is applicable to durability design of ordinary concrete structures and their members in house buildings, bridges, tunnels and other infrastructures and general structures in various natural environments.
This standard does not take into account the degradation of structural performance caused by low-cyclic reversed load and sustained load, and is thus not applicable to structures made of light aggregate concrete, fiber concrete, and other special concrete types, nor the design of concrete structure durability in special corrosive environments such as high temperature and high humidity environment, microbial corrosive environment, electromagnetic environment, high pressure environment, stray current and the like in industrial production.
1.0.3 The durability provisions of this standard are the minimum requirements to make the structure fulfill the design working life with the specified assurance rate. The design may be appropriately improved according to the specific characteristics of the project, local environmental conditions and practical experience, and specific construction conditions.
1.0.4 In addition to this standard, the design of concrete structure durability shall also comply with those stipulated in the current relevant standards of China.
2 Terms and symbols
2.1 Terms
2.1.1 environmental action
effects of the environmental factors such as temperature, humidity, and their variations, as well as carbon dioxide, oxygen, salt and acid on the structures and material performance
2.1.2 degradation
time-dependent performance attenuation of a material or structure in the environment
2.1.3 degradation model
a mathematical expression or test device describing the performance degradation process of a material or structure
2.1.4 structure durability
the capability of a structure or member to maintain their applicability and safety within the design working life under the environmental actions and normal maintenance and service conditions
2.1.5 atmospheric environment
environment without freeze-thaw, or action of chlorides and other chemical corrosive substances, to which concrete structures or members are exposed
2.1.6 freeze-thaw environment
environment where concrete structures or members are subjected to repeated freeze-thaw action
2.1.7 chloride environment
environment where concrete structures or members are subjected to invasion of chlorides, causing corrosion of internal reinforcement, including marine chloride environment and other chloride environments excluding cryohydrate
2.1.8 chemical environment
environment where concrete structures or members are subjected to corrosion of chemical substances in natural environment, including chemical environment in water and soil, and corrosion environment with atmospheric pollution
2.1.9 design working life
the working life of the structures or structural members specified in design, which can be fulfilled for intended purpose without major repair
2.1.10 chloride diffusion coefficient
the parameter representing the diffusion rate of chlorine ion from high concentration area to low concentration area in the concrete
2.1.11 durability factor
the ratio of the dynamic elastic modulus to the initial dynamic elastic modulus of concrete after a specified number of quick freeze-thaw cycles with standard test method, usually expressed as a percentage
2.1.12 air entrainment
technological measures to form uniform, stable and spherical closed micro air voids in concrete with surfactant during concrete mixing
2.1.13 air content in concrete
the ratio of the volume of air voids in concrete to the total volume of concrete, expressed as a percentage
2.1.14 spacing factor of air voids
a parameter representing the distance between edges of adjacent air voids in hardened concrete or cement paste
2.1.15 maintenance
various technical and management activities adopted to maintain the required performance of structures within the design working life
2.1.16 restore
the activity to restore the damaged structures to normal use through repair, replacement or reinforcement
2.1.17 major repair
the restoration activity requiring replacement of the damaged concrete or the main members in the structure, for which the normal use of the structure is stopped within a certain period of time
2.1.18 restorability
the capability of damaged structures or members for economically reasonable restoration
Foreword ii 1 General provisions 2 Terms and symbols 2.1 Terms 2.2 Symbols 3 General requirements 3.1 Design principles 3.2 Classes and intensities of environmental actions 3.3 Design working life 3.4 Requirements for materials 3.5 Requirements for detailing 3.6 Additional requirements for construction quality 4 Atmospheric environment 4.1 General requirements 4.2 Environmental action intensities 4.3 Thickness of materials and cover 4.4 Detailing and protective measures 5 Freeze-thaw environment 5.1 General requirements 5.2 Environmental action intensities 5.3 Thickness of materials and cover 5.4 Detailing and protective measures 6 Chloride environment 6.1 General requirements 6.2 Environmental action intensities 6.3 Thickness of materials and cover 6.4 Detailing and protective measures 7 Chemical environment 7.1 General requirements 7.2 Environmental action intensities 7.3 Thickness of materials and cover 7.4 Detailing and protective measures 8 Durability requirements for post-tensioned prestressed system 8.1 General requirement 8.2 Protection of tendons 8.3 Protection of anchorage end 8.4 Detailing and additional requirements for construction quality Annex A Quantitative method for design of concrete structure durability Annex B Selection of concrete raw materials Annex C Additional protective measures for concrete structures Annex D Air content and spacing factor of air void of air-entrained concrete Annex E Determination methods for concrete durability parameters and corrosive ion Explanation of wording in this standard List of quoted standards
1 General provisions
1.0.1 This standard is formulated in order to ensure the durability of concrete structures to fulfill the specified design working life and ensure the reasonable working life of engineering structures.
1.0.2 This standard is applicable to durability design of ordinary concrete structures and their members in house buildings, bridges, tunnels and other infrastructures and general structures in various natural environments.
This standard does not take into account the degradation of structural performance caused by low-cyclic reversed load and sustained load, and is thus not applicable to structures made of light aggregate concrete, fiber concrete, and other special concrete types, nor the design of concrete structure durability in special corrosive environments such as high temperature and high humidity environment, microbial corrosive environment, electromagnetic environment, high pressure environment, stray current and the like in industrial production.
1.0.3 The durability provisions of this standard are the minimum requirements to make the structure fulfill the design working life with the specified assurance rate. The design may be appropriately improved according to the specific characteristics of the project, local environmental conditions and practical experience, and specific construction conditions.
1.0.4 In addition to this standard, the design of concrete structure durability shall also comply with those stipulated in the current relevant standards of China.
2 Terms and symbols
2.1 Terms
2.1.1 environmental action
effects of the environmental factors such as temperature, humidity, and their variations, as well as carbon dioxide, oxygen, salt and acid on the structures and material performance
2.1.2 degradation
time-dependent performance attenuation of a material or structure in the environment
2.1.3 degradation model
a mathematical expression or test device describing the performance degradation process of a material or structure
2.1.4 structure durability
the capability of a structure or member to maintain their applicability and safety within the design working life under the environmental actions and normal maintenance and service conditions
2.1.5 atmospheric environment
environment without freeze-thaw, or action of chlorides and other chemical corrosive substances, to which concrete structures or members are exposed
2.1.6 freeze-thaw environment
environment where concrete structures or members are subjected to repeated freeze-thaw action
2.1.7 chloride environment
environment where concrete structures or members are subjected to invasion of chlorides, causing corrosion of internal reinforcement, including marine chloride environment and other chloride environments excluding cryohydrate
2.1.8 chemical environment
environment where concrete structures or members are subjected to corrosion of chemical substances in natural environment, including chemical environment in water and soil, and corrosion environment with atmospheric pollution
2.1.9 design working life
the working life of the structures or structural members specified in design, which can be fulfilled for intended purpose without major repair
2.1.10 chloride diffusion coefficient
the parameter representing the diffusion rate of chlorine ion from high concentration area to low concentration area in the concrete
2.1.11 durability factor
the ratio of the dynamic elastic modulus to the initial dynamic elastic modulus of concrete after a specified number of quick freeze-thaw cycles with standard test method, usually expressed as a percentage
2.1.12 air entrainment
technological measures to form uniform, stable and spherical closed micro air voids in concrete with surfactant during concrete mixing
2.1.13 air content in concrete
the ratio of the volume of air voids in concrete to the total volume of concrete, expressed as a percentage
2.1.14 spacing factor of air voids
a parameter representing the distance between edges of adjacent air voids in hardened concrete or cement paste
2.1.15 maintenance
various technical and management activities adopted to maintain the required performance of structures within the design working life
2.1.16 restore
the activity to restore the damaged structures to normal use through repair, replacement or reinforcement
2.1.17 major repair
the restoration activity requiring replacement of the damaged concrete or the main members in the structure, for which the normal use of the structure is stopped within a certain period of time
2.1.18 restorability
the capability of damaged structures or members for economically reasonable restoration
Contents of GB/T 50476-2019
Foreword ii
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 General requirements
3.1 Design principles
3.2 Classes and intensities of environmental actions
3.3 Design working life
3.4 Requirements for materials
3.5 Requirements for detailing
3.6 Additional requirements for construction quality
4 Atmospheric environment
4.1 General requirements
4.2 Environmental action intensities
4.3 Thickness of materials and cover
4.4 Detailing and protective measures
5 Freeze-thaw environment
5.1 General requirements
5.2 Environmental action intensities
5.3 Thickness of materials and cover
5.4 Detailing and protective measures
6 Chloride environment
6.1 General requirements
6.2 Environmental action intensities
6.3 Thickness of materials and cover
6.4 Detailing and protective measures
7 Chemical environment
7.1 General requirements
7.2 Environmental action intensities
7.3 Thickness of materials and cover
7.4 Detailing and protective measures
8 Durability requirements for post-tensioned prestressed system
8.1 General requirement
8.2 Protection of tendons
8.3 Protection of anchorage end
8.4 Detailing and additional requirements for construction quality
Annex A Quantitative method for design of concrete structure durability
Annex B Selection of concrete raw materials
Annex C Additional protective measures for concrete structures
Annex D Air content and spacing factor of air void of air-entrained concrete
Annex E Determination methods for concrete durability parameters and corrosive ion
Explanation of wording in this standard
List of quoted standards
