Standard No.:	NB/T 20021-2010
English Name:	Construction Technology Specification for Concrete Raft Foundation of Nuclear Island of PWR Nuclear Power Plant
Chinese Name:	压水堆核电厂核岛混凝土筏形基础施工技术规程
Professional Classification:	NB    Professional Standard - Energy
Issued by:	National Energy Administration
Issued on:	2010-5-1
Implemented on:	2010-10-1
Status:	valid
Language:	English
File Format:	PDF
Word Count:	8000 words
Price(USD):	300.0
Delivery:	via email in 1 business day

1 Scope This standard specifies requirements for the construction and quality acceptance of concrete raft foundation of PWR power plant nuclear island. This standard applies to the construction and quality acceptance of concrete raft foundation of PWR power plant nuclear island. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB 175 Common portland cement GB/T 1346 Test methods for water requirement of normal consistency, setting time and soundness of the portland cement GB 1499 Hot rolled Ribbed steel bars for the reinforcement of concrete GB/T 1596 Fly ash used for cement and concrete GB/T 8074 Testing method for specific surface of cement—Blaine method GB 8076 Concrete admixtures GB/T 12959 Test methods for heat of hydration of cement GB/T 14684 Sand for construction GB/T 17671 Method of testing cements—Determination of strength GB 50164 Standard for quality control of concrete GB 50204 Code for acceptance of constructional quality of concrete structures GBJ 107 Inspection and evaluation of concrete strength JC/T 603 Standard test method for drying shrinkage of mortar JGJ 52 Standard for technical requirements and test method of sand and crushed stone (or gravel) for ordinary concrete JGJ 55 Specification for mix proportion design of ordinary concrete JGJ 63 Standard of water for concrete JGJ 107 General technical specification for mechanical splicing of bars   3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 raft foundation of nuclear island (henceforth “raft foundation”) mainly including the raft foundations of reactor building, fuel building, balance of plant, and connecting buildings, among others. The raft foundation of reactor building is round, while those of the other buildings are roughly rectangular. The raft foundations in all cases are of a cast-in-place reinforced concrete structure with a thickness of 3m to 6m 3.2 mass concrete concrete with a structure size so large as to cause such a cracking in the structure due to the excessive temperature difference between the inside and outside of the concrete resulted from hydration heat of the cement that necessitates measures, e.g., for control of the temperature difference and the temperature drop rate, to reduce the tensile stress caused by the temperature difference inside the structure 3.3 type inspection comprehensive inspection of the product carried out for type appraisal in trail production in the case of a new product or production transferred to another factory, and for assessment of product performance impact and product quality stability, in terms of all the technical requirements specified in the product standard, on a regular basis in the case of normal production 3.4 preliminary test of concrete mix proportion datum mix proportion obtained completely by laboratory work with the indexes satisfied with the design requirements, to provide recommended mix proportions appropriate for acceptance tests, or to investigate the effects of various parameters so as to suggest guidance and corrective measures when necessary in the future 3.5 feasibility test of concrete (henceforth “feasibility test”) a series of tests to verify whether the concrete mix proportion determined in the preliminary test meets the specified requirements under the site conditions 3.6 concrete construction mix proportion (henceforth “construction mix proportion”) mix proportion intended for construction practice, which is obtained through calculation according to the feedstock properties and the technical requirements of concrete, adjustment by laboratory trail, i.e., preliminary test, verification by feasibility test, and modification to reflect the measured moisture content of the aggregates 3.7 open qualification concrete test to verify whether the performance indexes of the concrete mix proportion for initial use under certain working (environment) conditions, the workability and stability, among others, meet the specified requirements

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Basic requirements 5 Construction requirements 6 Concrete temperature control and monitoring 7 Acceptance of raft foundation 8 Quality documentation Annex A (Informative) Method for quick test on chloride ion content in cement (fly ash) (semi-quantitative method)