On November 27,
2023, the mandatory national standard GB 175-2023 "General Portland Cement" formulated by the Ministry of Industry and Information Technology was approved and issued by the State Administration of Market Supervision and Administration and the National Standardization Management Committee, and will be implemented on June 1, 2024. What impact will the
new standard bring to the production of cement industry? What changes should cement enterprises focus on?
No.1 Amendment implemented on September 1, 2009: Test Method for Chloride Ions in Cement" 8 "is changed to" 8 "0H Amendment No.2 of TML0 UNK4 implemented on December 1, 2015: 6.4 The strength grade of composite Portland cement is divided into 32.5 R, 42.5, 42.5 R, 52.5 and 52.0 HTML0 Amendment No.3 of UNK5 implemented on October 1, 2019: 6.4 The strength grade of composite Portland cement is divided into 42.5, 42.5R, 52.5, 52.0 HTML0UNK6 II. Revision of GB175-2023 "General Portland Cement" and its impact on enterprises 0 HTML 0 UNK 71. Cancellation of composite Portland cement 32.5 grade cement 0 HTML 0 UNK8 cement: Accelerate the formulation and revision of cement, concrete product standards and related design specifications, and promote the use of high-grade cement concrete. Cancellation of 32.5 composite cement product standard as soon as possible, gradual reduction of 32.0 HTML 0 UNK9 upgrading of cement products: stop production of 32.5 grade composite Portland cement, focus on production 42. Accelerate the development of special cement, aggregate, concrete admixture, ready-mixed concrete, ready-mixed mortar, cement products and component products. We will actively use solid wastes such as tailings and construction waste to replace natural resources, and develop machine-made sand and gravel, concrete admixtures, block wall materials, low-carbon cement and other products. Develop new cementitious materials such as magnesia cementitious materials. 0 HTML 0 UNK1 02. National standards are divided into mandatory standards and recommended standards, while industry standards and local standards are recommended standards. Mandatory standards must be implemented. The State encourages the adoption of recommendatory standards. 0 HTML0 UNK1 1 Article 10, Compulsory national standards shall be formulated for the technical requirements of safeguarding human health and safety of life and property, national security, ecological and environmental security, and meeting the basic needs of economic and social management. The relevant administrative departments of the State Council shall, in accordance with their duties, be responsible for proposing, organizing drafting, soliciting opinions and technical examination of compulsory national standards. 0HTML0Article 25 of the UNK1stipulates that products and services that do not conform to compulsory standards shall not be produced, sold, imported or provided. 0 HTML 0 UNK1 3 "Measures for the Administration of Compulsory National Standards" (promulgated by Decree No.25 of the State Administration of Market Supervision and Administration on January 6, 2020) 0 HTML 0 UNK1 4 Article 19, the technical requirements of compulsory national standards shall be mandatory, verifiable and operable. 0 HTML0 UNK1 53. Raw material requirements for cement production adjusted 0 HTML0 UNK1 6 (1) to 0 HTML0 UNK1 7 < a Href = "https://price.ccement.com/Price_list-1-s0-e0-p0-c0-k100059-b0.0HTML0UNK18 (2) for slag, fly ash, Requirements for pozzolanic mixed materials 0 HTML0 UNK1 9 In order to make full, rational and scientific use of industrial waste slag, the activity level (such as activity index and 28 d compressive strength ratio) of granulated blast furnace slag, fly ash and pozzolanic mixed materials is no longer required in this standard revision; other technical requirements should meet the requirements of relevant standards respectively. 0 HTML0 UNK2 0 About fly ash: This standard revision stipulates that fly ash should meet the technical requirements specified in GB/T 1596 (except for strength activity index and alkali content). The limit of ammonium ion in fly ash is not more than 210 mg/kg, and the test is carried out according to the method specified in GB/T 39701. 0 HTML 0 UNK2 1 (3) Types of Admixtures Allowed for General Portland Cement in China 0 HTML 0 UNK2 2 The following table shows the types of admixtures for general Portland cement in several representative countries (or organizations) in the world. The mixed materials used are concentrated in the three categories of slag, pozzolanic admixture and fly ash, with only minor differences. For example, the United States does not have a separate list of fly ash (fly ash is a pozzolanic material), the European Union lists burned shale (which is a pozzolanic material) and silica fume separately, while China refines the pozzolanic materials into 10 kinds and lists limestone and sandstone separately. Therefore, the varieties of mixed materials in China are basically the same as those in the world, or even more. Kiln ash has been cancelled in this standard revision. 0HTML0UNK23GB/T Pozzolanic admixture 0 HTML0 UNK2 44.2 Artificial pozzolanic admixture 0 HTML0 UNK2 54.2.0 HTML0 UNK2 64.2.0 HTML0 UNK2 74.2.0 HTML0 UNK2 84.2. 0 HTML0 UNK2 94.2.0 HTML0 UNK3 04.1.0 HTML0 UNK3 14.1.0 HTML0 UNK3 24.1.0 HTML0 UNK3 34.1.0 HTML0 UNK3 44.1.0 HTML0 UNK3 5 (4) Characterization and qualification of limestone and sand using methylene blue values Clay content in rock 0 HTML0 UNK3 6 The methylene blue value is generally used to characterize and limit in the world, such as ASTM C595, EN197-1, etc. The methylene blue value is also used in GB/T35164-2017 Limestone Powder Used in Cement, Mortar and Concrete promulgated and implemented in China in 2017. 0 HTML0 UNK3 7 Therefore, the methylene blue value and the limit of GB/T35164-2017 Limestone Powder Used in Cement, Mortar and Concrete are used in this standard revision. The methylene blue value is tested according to the provisions of Annex A of GB/T35164-2017. 0HTML0UNK384.0HTML0UNK39
0 Portland Slag Cement Composition Revision: The substitute admixture is one of fly ash or pozzolanic admixture or limestone.After substitution, the slag/slag powder content (mass fraction) in P · S · A slag Portland cement is not less than 21% of the cement mass, and the slag/slag powder content (mass fraction) in P · S · B slag Portland cement is not less than 51% of the cement mass, so as to ensure the basic performance of slag cement. Composition of Portland
Fly Ash Cement and Portland Pozzolana Cement Revised to allow up to 5% of limestone to be substituted for the main blending material. The content (mass fraction) of the fly ash in the substituted fly ash Portland cement is not less than 21% of the cement mass, and the content (mass fraction) of the pozzolanic admixture in the pozzolanic Portland cement is not less than 21% of the cement mass.
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At the same time, https://img7.ccement.com/richtext/img/pjxwbuc8js81712124594047., the provision for substitution of mixed materials has been removed.". Limestone content is an inert material and its increase will lead to the deterioration of cement performance (such as increased brittleness, easy bleeding and sanding, etc.). This standard revision gives a limit value, which is less than 15% of the cement mass.
of technical index of https://img7.ccement.com/richtext/img/qwwp52suhj71712124614693.5.
cement: 1. Limit
of chloride ion in cement According to the opinions of the technical review meeting organized by the Ministry of Industry and Information Technology on December 23, 2021, 0 is reserved.
Second, the limit of magnesium oxide in cement and autoclave stability
. This standard revision takes autoclave stability as a type inspection item.
Third, the standard revision of alkali content
in cement cancels the requirement of alkali content and takes it as a selective index; When the user requests to provide < a href = "https://www.ccement.
4 is 3D strength
of cement", this standard revision refers to EN197-1 to simplify the setting of strength index, and no longer sets different 3D strength index of cement according to the type of cement. Instead, the values were set at intervals of 5 MPa on the basis of the 3D strength of Portland cement and ordinary Portland cement.
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Portland cement, Portland slag cement, Portland fly ash cement, The fineness of pozzolanic Portland cement and composite Portland cement shall be represented by the residue on a 45 μm square mesh sieve, which shall not be less than 5%.
When the user has special requirements, this standard allows the buyer and seller to negotiate the fineness index value.
6.
Fifth, the time limit
of quality arbitration inspection The time limit of quality arbitration inspection is as follows: the time limit based on the inspection results of physical samples is 40 days; the time limit based on the inspection report of the manufacturer's cement with the same number is 90 days.
7.
