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GB/T 21371-2019 PDF English


Search result: GB/T 21371-2019 English: PDF (GB/T21371-2019)
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GB/T 21371-2019English100 Add to Cart 0-9 seconds. Auto-delivery. By-product gypsum used in cement Valid
GB/T 21371-2008English279 Add to Cart 3 days By-product gypsum used in cement Obsolete
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GB/T 21371-2019: PDF in English (GBT 21371-2019)

GB/T 21371-2019 NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 91.100.10 Q 11 Replacing GB/T 21371-2008 By-Product Gypsum Used in Cement ISSUED ON: OCTOBER 18, 2019 IMPLEMENTED ON: SEPTEMBER 01, 2020 Issued by: State Administration for Market Regulation; Standardization Administration of the People’s Republic of China. Table of Contents Foreword ... 3 1 Scope ... 5 2 Normative References ... 5 3 Terms and Definitions ... 5 4 Technical Requirements ... 6 5 Test Methods ... 7 6 Judgment Rules ... 8 7 Transportation and Storage ... 9 By-Product Gypsum Used in Cement 1 Scope This Standard specifies the terms and definitions, technical requirements, test methods and judgment rules, transportation and storage of industrial by-product gypsum used in cement. This Standard is applicable to the acceptance and use of industrial by-product gypsum for adjusting the setting time of cement. 2 Normative References The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this document. GB/T 1346 Standard Test Method for Water Requirement for Normal Consistency Setting Time and Soundness of the Portland Cement GB/T 2419 Test Method for Fluidity of Cement Mortar GB/T 5483 Natural Gypsum GB/T 5484 Methods for Chemical Analysis of Gypsum GB 6566 Limit for Radionuclides in Building Materials GB/T 17671 Test Method of Cement Mortar Strength (ISO Method) JC/T 1083 Test Method for Compatibility of Cement and Water-Reducing Agent 3 Terms and Definitions For the purposes of this Document, the following terms and definitions apply. 3.1 By-product gypsum The general term for by-products with calcium sulfate as the main component that are discharged from industrial manufacturing. NOTE 1: Also known as chemical gypsum, synthetic gypsum. S – mass fraction of SO3, expressed by percentage (%); w – mass fraction of crystal water, expressed by percentage (%). 5.3 Radioactive material limits It shall be tested according to GB 6566. 5.4 Influence of industrial by-product gypsum on cement properties 5.4.1 Preparation of contrast cement It is the P·I Portland cement, which is prepared by the Category-G and Class-2 above (including Class-2) gypsum specified in GB/T 5483, with SO3 content of 2.0%~2.5%, 80μm sieve residue of less than 4%, and specific surface area of 350m2/kg±10m2/kg. 5.4.2 Preparation of test cement It is P·I Portland cement that is prepared by using Portland cement clinker for preparing contrast cement and by replacing natural gypsum with 30%~100% of the assessed industrial by-product gypsum. During the preparation, the 80μm sieve residue of the cement shall be controlled to less than 4%, the specific surface area shall be within the range of 350m2/kg ± 10m2/kg, and the difference between the SO3 content and the contrast cement SO3 content shall be within 0.2%. 5.4.3 Standard consistency water consumption, setting time and stability of cement It shall be tested according to GB/T 1346. 5.4.4 Fluidity of cement mortar The preparation of cement mortar is carried out according to GB/T 17671; and the fluidity test operation of cement mortar is carried out according to GB/T 2419. 5.4.5 Strength of cement mortar It shall be tested according to GB/T 17671. 5.4.6 Compatibility of cement and water-reducing agent It shall be tested according to JC/T 1083. 6 Judgment Rules When any one of 4.1, 4.3, 4.4, 4.5 and 4.6 does not meet the requirements of this Standard, it cannot be used in the manufacturing of cement. ......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.